MICHIGAN
INTERSECTION
GUIDE
July 2008
MICHIGAN INTERSECTION GUIDE
TABLE OF CONTENTS
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
Introduction..................................................................................................1
Basic Terminology and Information............................................................1
Planning .......................................................................................................4
3.1
Design Considerations and Objectives ............................................4
3.2
Locations Needing Careful Review .................................................5
3.3
Data for Operational Review/Feasibility .........................................5
Safety ..........................................................................................................5
Design Information ......................................................................................6
Operational Analysis....................................................................................6
MDOT Intersection Comparison Matrix Tool.............................................8
Miscellaneous Topics.................................................................................11
APPENDIX A
Strategies to Improve Safety and Operations at Signalized Intersections
Strategies to Improve Safety and Operations at Unsignalized Intersections
APPENDIX B
MDOT Roundabout Quick Guide
APPENDIX C
Intersection Crash Reports (2004-2006)
APPENDIX D
Intersection Conflict Diagrams
APPENDIX E
MDOT’s Crash Reduction Factors for Various Countermeasures (January 2008)
CREDITS
This document was prepared by Wilcox Professional Services, LLC under the direction
of MDOT’s Intersection Committee which consists of the following individuals:
Jack Benac
Imad Gedaoun
Stephanie Palmer
Terry Palmer
Bob Rios
REFERENCES
1. A Policy on Geometric Design of Highways and Streets, American Association of
State Highway and Transportation Officials, 2004
2. NCHRP Report 500, Guidance for Implementation of the AASHTO Strategic
Highway Safety Plan, Transportation Research Board, 2003
3. Michigan Manual on Uniform Traffic Control Devices, Federal Highway
Administration and MDOT, 2005
4. Traffic and Safety Notes, Michigan Department of Transportation – Traffic and
Safety
5. Unconventional Arterial Intersection Design, Management and Operations
Strategies, Parsons Brinckerhoff Quade and Douglas, Inc., 2003
6. MDOT Geometric Design Guide
7. MDOT Road Design Manual
8. MDOT Sight Distance Guidelines
9. MDOT Signing Design, Placement , and Application Guidelines
10. MDOT Traffic Signal Guidance for Vehicle Change Intervals
11. Guidelines for Four-Lane to Three-Lane Conversions, Michigan State University,
2001
12. Guide for the Development of Bicycle Facilities, American Association of State
Highway and Transportation Officials
13. Older Driver Highway Design Handbook, Federal Highway Administration
14. Traffic Engineering Handbook, Institute of Transportation Engineers
1.0 Introduction
The American Association of State Highway and Transportation Officials (AASHTO)
defines an intersection as the general area where two or more highways join or cross,
including the roadway and roadside facilities for traffic movements within the area.
Intersections are an important part of a highway facility because the efficiency, safety,
speed, cost of operation, and capacity of the facility depend on their design.
The Intersection Guide is a summary that describes the different types of intersections,
identifies some of the situations where different types of intersections could be used,
outlines countermeasures that are available to correct deficiencies, and estimates maximum
capacities for various types of intersections.
Appendix A is a more thorough description of strategies to improve safety and operations
at signalized and unsignalized intersections. Included in Appendix B is The Roundabout
Guide, which contains information regarding roundabout planning, safety, geometric
design, pavement markings and signing, public involvement, and other design/operational
considerations. The guide also contains crash history data in Appendix C that can help the
engineer determine whether the crash experience at an existing site is above the average for
similar intersections within defined traffic volume ranges and geographic locations.
Conflict diagrams are included in Appendix D that show conflicts for different types of
intersections. Appendix E includes the MDOT crash reduction factors for various
countermeasures.
2.0 Basic Terminology and Information
The basic types of intersections are the three-leg or T, the four-leg, multileg, and
roundabouts. At each particular location, the intersection type is determined by the
number of intersections legs, whether or not the highway is divided, the topography, the
traffic volumes, patterns, and speeds, and the desired type of operation. A brief discussion
of these intersection types follows. The basic intersections types vary greatly in scope,
shape, and degree of channelization. More detailed information regarding intersection
types and examples are provided in AASHTO’s “A policy on Geometric Design of
Highways and Streets” (The Green Book) and the MDOT Geometric Design Guides.
Three-Leg or T-Intersections- The normal pavement widths of both highways should be
maintained at T-intersections except for the paved returns or where widening is needed to
accommodate large commercial vehicles, or where auxiliary turn lanes are needed to
improve safety and capacity for turning vehicles. Typical T-intersection details are shown
in Geometric Design Guide VII-650, and the Green Book in Chapter 9. Guidelines for
auxiliary lanes are found in the Traffic and Safety Notes 603 (7.3), 604 (7.5) and 605 (7.6).
Four-Leg Intersections- Four-leg intersections vary from the simple intersection of two
lightly traveled local streets to complex intersection of two main highways. The overall
design principles, channelization, use of auxiliary lanes, and traffic control vary greatly
depending on human factors, traffic considerations, physical elements, and economic
1
factors. Typical four-leg intersections are shown in Geometric Design Guide VII-650, and
VII-670, and the Green Book in Chapter 9. Guidelines for auxiliary lanes are found in the
Traffic and Safety Notes.
Multileg Intersections- Intersections with more than four legs are seldom used and should
be avoided where possible. Most often they are found in urban areas where traffic volumes
are light and stop control is used. Sometimes safety and efficiency can be improved by
eliminating some the movements or legs, or constructing a roundabout.
Roundabouts- Road junction at which traffic enters a counter clockwise, one-way stream
around a central island. See MDOT Roundabout Quick Guide in Appendix B.
Alternative Intersection Designs- There are several innovative intersections designs,
shown in the “Green Book,” that have been used in Michigan and other states. Some of
these designs include:
•
Median U-Turn Crossovers- See the “Green Book” Chapter 9, Exhibit 9-91, and
Geometric Design Guide VII-670. This design utilizes u-turn directional
crossovers, located approximately 600-700 ft from the crossroad, for the
redirection of left turns vehicles.
M-59 (Highland Rd) and Hickory
Ridge Rd – Median U-Turn
Crossovers
2
•
Jughandles- See the “Green Book” Chapter 9, Exhibit 9-88, 9-89, 9-93. This
design has been used in Michigan to a limited extent. In a jughandle, the ramp
leaves before the intersection and left turning traffic turns left off it rather than the
through road. In a reverse jughandle, the ramp leaves after the intersection and left
turning traffic loops around to the right and merges with the crossroad before the
intersection. The jughandle movement eliminates direct left turns at the cross
street intersection reducing delay to though traffic. The jughandle design also
includes what is commonly referred to as ground loops, which have also been used
in Michigan.
M-53 (Van Dyke Ave) and
15 Mile Rd – Reverse Jughandle
US-24 (Telegraph Rd) and M-153
(Ford Rd) – Jughandle & Quadrant
Roadway
Pennsylvania Ave and Cedar St –
Ground Loops
3
•
Quadrant Roadway – Michigan has used at-grade left turn ramps, in advance of the
cross road intersection, to direct the left turns to the crossroad. All left turns are
removed from the primary intersection.
US-24 (Telegraph Rd) and Plymouth Rd – Quadrant
Roadway with U-turn directional crossovers to redirect
left turns.
•
Bowties, superstreets, paired intersections, continuous flow, flyover intersectionsThese are some other innovative designs being used by other states. See a study
done by Parsons Brinkerhoff Quade and Douglas, Inc, entitled “Unconventional
Arterial Intersection Design, Management, and Operations Strategies” for more
information.
3.0 Planning
3.1 Design Considerations and Objectives
The main objectives of intersection design are to facilitate the safe and efficient
movements of vehicles, bicyclists, and pedestrians. Basic elements to consider in
intersection design are discussed in AASHTO documents and include the following:
• Human Factors- include driving habits, ability to make decisions, driver
expectancy, decision reaction times, pedestrian and bicyclist use, and habits.
• Traffic Considerations- include design hour movements, capacity, size and
operating characteristics of vehicles, speeds, crossing distances, traffic control
devices, complexity, crash experience, bicycle and pedestrian movements, traffic
growth and/or future developments.
• Physical Elements- include vertical and horizontal alignment, sight distance, angle
of intersection, conflicts, speed-change lanes, traffic control devices, lighting,
drainage features, environmental factors, pedestrian facilities, driveways, medians
and islands.
• Economic Factors- include cost of improvements, energy consumption, delay, cost,
air quality, right of way available, number of approach lanes, and number of legs.
4
3.2 Locations Needing Careful Review
Any intersections with a Level of Service worse than D or higher than average crash
experience may justify an operational analysis to determine if corrective measures are
warranted. Corrective measures are detailed in 4.0 Safety section.
3.3 Data for Operational Review/Feasibility
During the scoping phase of a project, data is required to adequately analyze the operations
of an intersection and possible improvement options. Data that is typically needed to
evaluate an intersection includes the following:
• Existing and future AM and PM peak traffic movements
• Design vehicle identification including percentage of trucks
• Existing intersection geometrics
• Right of Way
• Crash data and pattern identification for 3 years, 7 years if fatal crash occurred
• Utility information
• Location of access points
• Pedestrian and bicyclist needs
• Transit stop locations
• Sight distances
• Physical inventory including: existing traffic control devices, signs, signals,
pavement markings, visibility of traffic control devices, driveway locations, fixed
objects, guardrail, pavement conditions, curb conditions, and drainage
• Operational review including: length of traffic queues, signal timing, erratic
maneuvers, vehicles having problems turning, weaving or merging, pedestrian
vehicle conflicts, evidence of hit objects at intersection
4.0 Safety
General
Intersections constitute only a small part of the overall highway system, yet intersection
related crashes in Michigan constitute more than 24 percent of fatal crashes in 2006 (258
fatalities) and 30 percent of all the reported crashes (93,790 crashes). It is not unusual that
crashes are concentrated at intersections because they are the point on the roadway system
where traffic movements most frequently conflict with one another. Good geometric
design combined with proper traffic control can result in an intersection that operates
efficiently and safely.
The following charts depict the percentage of 2006 Michigan intersection crashes by traffic
control type.
5
Fatal Crashes
None of
These
24%
Unknown
2%
All Crashes
None of
These 25%
Signal
32%
Unknown
2%
Signal 47%
Yield Sign
2%
Yield Sign
2%
Stop Sign
40%
Signal
Stop Sign
Yield Sign
Stop Sign
24%
None of These
Unknown
Signal
Stop Sign
Yield Sign
None of These
Unknown
Appendix A is an in depth discussion of strategies to improve safety and operations at
signalized and unsignalized intersections. Appendix B is the MDOT Roundabout Quick
Guide. Appendix C is historical crash data for various types of intersections on the state
trunkline system. It includes the average number of crashes and crash types for different
types of intersections at different ADT levels. The data can be used to determine if an
existing intersection has more than the average number of crashes when compared to
similar locations. When reviewing crashes, special attention should be given to the
severity of the crashes even if the total number of crashes is lower than the average for
similar intersections. Conflict diagrams are included in Appendix D that show conflicts
for different types of intersections. Appendix E includes the MDOT crash reduction
factors for various countermeasures.
5.0 Design Information
Guidance for developing intersection geometrics can be found in the AASHTO Green
Book, MDOT Geometric Design Guides, and the Road Design Manual (Chapter 3).
Guidance for developing roundabouts can be found in Section 4 of MDOT’s Roundabout
Guidance Document.
6.0 Operational Analysis
An operational analysis of any intersection type, except roundabouts can be completed
using The Highway Capacity Manual or SYNCHRO software package.
The following tables estimate the hourly capacity of different intersections with different
traffic control:
T-Intersection (Two-Lane Highway) STOP Control
One Lane Approach on All Legs
1400 vph for entire intersection
With CLFLT on All Approaches
1600 vph for entire intersection
T-Intersection (Two-Lane Highway) ALL-WAY STOP Control
One Lane Approach on All Legs
1400 vph for entire intersection
With CLFLT on All Approaches
1650 vph for entire intersection
6
T-Intersection (Two-Lane Highway) Signal Control
One Lane Approach on All Legs
2400 vph for entire intersection
With Left Turn Lanes on All Approaches
3550 vph for entire intersection
Four-Leg Intersection (Two-Lane Highway)
2-Way Stop Control 1 Lane Approach All
1300 vph for entire intersection
Legs
2-Way Stop Control + CLFTL All Legs
1550 vph for entire intersection
4-Way Stop Control 1 Lane Approach All
1400 vph for entire intersection
Legs
4-Way Stop Control + CLFTL All Legs
1600 vph for entire intersection
Signal Control With CLFTL All Legs
3700 vph for entire intersection
Signal + Left & Right Turn Lanes All Legs 4000 vph for entire intersection
Four-Leg Intersection (Four-Lane Highway)
Signal Control With CLFTL All Legs
5150 vph for entire intersection
2-Way Stop
1400 vph for entire intersection
Four-Leg Intersection (Divided Highway) Signal Control
(All left turns redirected to U-turn crossover)
Four-Lane Divided
6200 vph for entire intersection
Four-Lane + Right Turn Lanes (Mainline)
7500 vph for entire intersection
Six-Lane Divided
7850 vph for entire intersection
Six-Lane + Right-Turn Lanes (Mainline)
8350 vph for entire intersection
Eight-Lane Divided
8300 vph for entire intersection
Eight-Lane + Right-Turn Lanes (Mainline) 8650 vph for entire intersection
Typical Roundabout Capacities
Type of Roundabout
Single Lane
Two-Lane
Three-Lane
Approximate Peak Hour Capacity
Up to 2,000 vph for all approaches
Up to 4,000 vph for all approaches
Up to 7,000 vph for all approaches
7.0 MDOT Intersection Comparison Matrix Tool
MDOT’s evaluation matrix aids in the decision making process. The matrix includes a list
of information that can be used to evaluate different intersection alternatives.
7
Road Improvement
Alternatives/Options
Total Cost
Estimate*
Control Delay**
Level of
Service
Design Life
Cost/Benefit
Ratio***
Safety Benefits
ROW Impacts
(acres)
Environmental
Issues
Potential Utility
Conflicts
Construction
Impacts
Driveway
Accommodation/
Good Access
Management
Public Input/
Community
Support
MDOT Intersection Comparison Matrix Tool (For Safety, Scoping, and EPE Studies)*
* Additional information regarding this matrix can be found on the next page.
** Roundabout delays from Rodel are stop delay, while delay for other intersections in HCS/Synchro are control delay. In order to evenly compare these numbers, geometric delay should be added to roundabout stop delay from Rodel to get
control delay. See MDOT’s Roundabout Guidance Document for more information on calculating roundabout geometric delay.
***For more information regarding C/B methodology, see page 10 of this document.
The following criteria may also be helpful for comparing alternatives:
•
•
•
•
•
•
•
•
•
•
•
Is funding available?
Are traffic counts/projections available (Existing, 10-year, or 20-year)?
Does the alternative create the potential for enhancements?
Are bike/pedestrian facilities present or planned?
Are bike accommodations required?
What is the percentage of heavy truck traffic?
Is the intersection designed for trucks?
Is the intersection located within a system of progressed traffic signals?
Is the intersection adjacent to bridge or railroad crossing?
Is the intersection adjacent to another intersection?
Pedestrian Count___________
8
MDOT INTERSECTION COMPARISON MATRIX
Below is a brief description of all of Matrix items.
•
•
•
•
•
•
•
•
•
•
•
•
•
Road Improvement Alternatives/Options – Alternatives are the potential solutions being
considered for each location. Options are variations within an alternative. (e.g., for Alternative 1
- Upgraded Signalized Intersection, there could be two options which are Alternative 1a Upgraded Signalized Intersection with dual left turn lanes and Alternative 1b - Upgraded
Signalized Intersection with single left turn lanes and different signal timing.)
Cost Estimate – Total cost. Can consist of safety, CMAQ, R&R, EDA, capacity, local, etc.
Delay – Average seconds of control delay per vehicle as defined in the Highway Capacity
Manual
LOS – Level of Service
Design Life – Typical 10 or 20 years
Cost Benefit Ratio (C/B) – Includes maintenance and safety and delay costs (see the following
page for calculations)
Safety Benefits – Text description of potential safety improvements
ROW Impacts – Text description and acreage of impacts
Environmental Issues – Text description of any potential environmental impacts (e.g. wetlands,
cultural resources, etc.)
Potential Utility Conflicts – Text description of potential utility conflicts (e.g. water/sewer lines,
utility poles, etc.)
Construction Impacts – Text description of construction on local roads, business, traffic etc.
Driveway/Access Management – Text description of how easy the project will fit relative to other
options
Public Input/Community Support – Input on each option
9
C/B =
Ratio
T+[(M+E) X L]
[(D+A) x L]
T
=
Total Cost: All costs related to the proposed alternative including PE, CE
and Right-of-Way costs.
M
=
Maintenance Cost: All anticipated yearly maintenance cost in dollars per
year. Typical yearly maintenance cost for a signalized intersection is
$1200, and a roundabout is $0.00.
E
=
Energy Cost: The total expected yearly energy cost in dollars per year.
Typical energy cost for signalized intersection is $550, and a roundabout
is $1800.
L
=
Design Life: The projected design life for all options. Typically this
value is 20 years.
A
=
Accident Reduction Factor: The annual benefit from the reduction of
crashes. This value is provided by MDOT Traffic and Safety staff.
D
=
Average Delay Cost: The total benefit from the reduction in delay
between the existing condition and proposed alternative. It is calculated as
follows:
D
=
[Delay (Existing*) – Delay (Proposed*)] x ADT x N x Z
3600
Delay =
Calculation of Cost/Benefit
AM peak delay**(sec/veh) + PM peak delay** (sec/veh)
2
*
The above delay should be computed for the existing conditions with future
projected traffic volumes and for the proposed conditions with the projected 20
year traffic volumes for each alternative.
**
Add geometric delay for roundabouts according to the MDOT Roundabout Guide
to the average delay provided by RODEL.
ADT =
ADT =
Average daily traffic. If not known, compute as follows:
(AM + PM peak volumes) x 10
2
N
=
Number of days per year (365 days)
Z
=
Hourly delay Cost/Vehicle ($14.83). This dollar value should be updated
yearly.
10
8.0 Miscellaneous Topics
More detailed information for the following topics may be found on MDOT’s website
www.michigan.gov/mdot and in the following documents:
•
•
•
•
•
Intersection Design – MDOT Geometric Design Guides, MDOT Road Design
Manual and MDOT Traffic & Safety Notes
Sight Distance – AASHTO “Green Book,” MDOT Sight Distance Guidelines
Signals – MMUTCD, Highway Capacity Manual, ITE Traffic Engineering
Handbook, MDOT Traffic Signal Special Details, Michigan Signal Optimization
Guidelines, and Michigan Timing Permit Development
Signing – MMUTCD, MDOT Standard Highway Sign, MDOT Sign Support
Special Details/Standard Plans, MDOT Signing Design, Placement, and
Application Guidelines and MDOT Traffic & Safety Notes
Pavement Markings – MMUTCD, MDOT Pavement Marking Special
Details/Standard Plans and MDOT Traffic & Safety Notes
11
APPENDIX A
TABLE OF CONTENTS
Strategies to Improve Safety and Operations at Signalized Intersections
..........................................................................................................1
1.0
Reduce Frequency and Severity of Intersection Conflicts Through Traffic Control
and Operational Improvements....................................................................1
1.1
Employ Multiphase Signal Operation..............................................1
1.1.a Protected Left Turns
1.1.b Use Split Phases
1.2
Optimize Clearance Intervals...........................................................4
1.3
Evaluations – Left/Right Turn Maneuvers at Signalized Intersections
..........................................................................................................5
1.4
Coordinate Signals ...........................................................................6
1.5
Improve Operation of Pedestrian and Bicycle Facilities at Signalized
Intersections .....................................................................................6
1.6
Remove Unwarranted Signals..........................................................7
2.0
Reduce Frequency and Severity of Intersection Conflicts Through Geometric
Improvements ..............................................................................................8
2.1
Provide or Improve Left-Turn Channelization ................................8
2.1.a Install Left-Turn Lanes
2.1.b Improve Left-Turn Lane Geometry
2.1.c Lengthen Left-Turn Lane
2.1.d Provide Positive Offset for Left-Turn Lanes
2.1.e Delineate Turn Path
2.1.f Four-Lane to Three-Lane Conversion
2.2
Provide or Improve Right-Turn Lanes...........................................10
2.2.a Construct Right-Turn Lanes
2.2.b Lengthen Right-Turn Lanes
3.0
Improve Geometry of Pedestrian, Bicycle, and Transit Facilities .............11
4.0
Revise Geometry of Complex Intersections ..............................................13
4.1
Convert One Four-Leg Intersection to Two T-Intersections .........13
4.2
Convert Two T-Intersections to One Four-Leg Intersection .........14
4.3
Improve Intersection Skew Angle .................................................14
4.4
Remove Deflection in Through-Vehicle Travel Path ....................15
4.5
Close Intersection Leg ...................................................................15
5.0
Construct Special Solutions .......................................................................15
5.1
Provide Indirect Left Turns............................................................16
5.2
Convert Two-Way Streets to a One-Way Pair...............................16
6.0
Improve Sight Distance at Signalized Intersections ..................................17
6.1
Clear Sight Triangles .....................................................................17
6.2
Redesign Intersection Approaches.................................................17
7.0
Improve Driver Awareness of Intersections and Signal Control ...............18
7.1
Improve Visibility of Intersections on Approaches .......................18
7.2
Improve Signing and Delineation ..................................................18
7.3
Install Larger Signs ........................................................................19
7.4
Provide Intersection Lighting ........................................................19
7.5
Install Rumble Strips on Approaches ............................................19
7.6
Install Queue Detection System.....................................................19
7.7
Improve Visibility of Signals and Signs at Intersection ................20
8.0
Improve Access Management Near Signalized Intersections....................20
8.1
Restrict Access to Properties Using Driveway Closures or Turn
Restrictions ................................................................................................21
8.2
Restrict Cross-Median Access Near Intersections.........................21
9.0
Improve Safety Through Other Infrastructure Treatments ........................22
9.1
Improve Drainage in Intersection and on Approaches ..................22
9.2
Provide Skid Resistance in Intersection and on Approaches.........22
9.3
Restrict or Eliminate Parking on Intersection Approaches............22
Strategies to Improve Safety and Operations at Unsignalized
Intersections ......................................................................................................24
1.0
Improve Management of Access Near Unsignalized Intersections ...........24
1.1
Implement Driveway Closures/Relocations ..................................24
1.2
Implement Driveway Turn Restrictions.........................................24
2.0
Reduce the Frequency and Severity of Conflicts Through Geometric
Improvements ............................................................................................25
2.1
Provide Left-Turn Lanes at Intersections ......................................25
2.2
Provide Longer Left-Turn Lanes at Intersections..........................25
2.3
Provide Offset Left-Turn Lanes at Intersections ...........................25
2.4
Provide Passing Flares on Shoulders at T-Intersections ................26
2.5
Provide Right-Turn Lanes at Intersections ....................................26
2.6
Provide Longer Right-Turn Lanes at Intersections........................26
2.7
Provide Offset Right-Turn Lanes at Intersections .........................27
2.8
Provide Full-Width Paved Shoulders in Intersection Areas ..........27
2.9
Restrict or Eliminate Turning Maneuvers by Signing ...................27
2.10 Close or Relocate “High-Risk” Intersections ................................28
2.11 Convert One Four-Leg Intersection to Two T-Intersections .........28
2.12 Convert Offset T-Intersections to a Four-Leg Intersection............28
2.13
2.14
Realign Intersection Approaches to Reduce or Eliminate Intersection
Skew...............................................................................................29
Use Indirect Left-Turn Treatments to Minimize Conflicts at Divided
Highway Intersections ...................................................................29
3.0
Improve Pedestrian and Bicycle Facilities to Reduce Conflicts Between Motorists
and Non-Motorists .....................................................................................30
4.0
Improve Sight Distance..............................................................................30
4.1
Improve Intersection Sight Distance at Unsignalized Intersections
........................................................................................................30
4.2
Clear Sight Triangles in the Medians of Divided Highways Near
Intersections ...................................................................................31
4.3
Change Horizontal and/or Vertical Alignment of Approaches to Provide
More Sight Distance ......................................................................31
4.4
Eliminate Parking that Restricts Sight Distance ............................31
5.0
Improve Driver Awareness of Intersections as Viewed from the Intersection
Approach....................................................................................................32
5.1
Improve Visibility of Intersection by Providing Enhanced Signing and
Delineation.....................................................................................32
5.2
Improve Visibility of Intersection by Providing Lighting .............32
5.3
Install Larger Regulatory and Warning Signs at Intersections ......32
5.4
Call Attention to the Intersection by Installing Rumble Strips on
Intersection Approaches.................................................................33
5.5
Provide Supplementary Stop Signs Mounted Over the Roadway .33
5.6
Provide Pavement Markings with Supplementary Messages, Such as
STOP AHEAD...............................................................................34
5.7
Install Intersection Control Beacons at Stop-Controlled Intersections
........................................................................................................34
6.0
Choose Appropriate Intersection Traffic Control to Minimize Crash Frequency
and Severity ...............................................................................................34
6.1
Avoid Signalizing Through Roads.................................................34
6.2
Provide All-Way Stop Control at Appropriate Intersections.........35
6.3
Provide Roundabouts at Appropriate Locations ............................35
7.0
Guide Motorists More Effectively Through Complex Intersections .........35
7.1
Provide Turn Path Markings..........................................................35
7.2
Provide Lane Assignment Signing or Marking at Complex
Intersections ...................................................................................36
Strategies to Improve Safety and Operations at Signalized
Intersections
The strategies for improving safety at signalized intersections are outlined below.
Physical improvements include both geometric design modifications and changes to
traffic control devices.
1.0
Reduce Frequency and Severity of Intersection Conflicts Through Traffic
Control and Operational Improvements
Virtually all traffic signal timing and phasing schemes are established with the primary
objective being the safe and efficient movement of traffic. Certain timing, phasing, and
control strategies can produce safety benefits with only marginal adverse effects on delay
or capacity. Low-cost improvements to signalized intersections that can be implemented
in a short time period include revising the signal phasing and/or operational controls at
the intersection to explicitly address safety concerns.
Signalization improvements may include adding phases, lengthening clearance intervals,
eliminating or restricting higher-risk movements, optimizing timing, and coordinating
signals. Installing push buttons for pedestrians crossing the trunk line can increase the
green time for trunk line traffic. A review of crash history at a specific signalized
intersection can provide insight into the most appropriate strategy for improving safety at
the intersection.
1.1
Employ Multiphase Signal Operation
This strategy includes using protected left-turn phases and split phases.
A two-phase signal is the simplest method for operating a traffic signal, but
multiple phases may be employed to improve intersection safety. Left turns are
widely recognized as the highest-risk movements at signalized intersections.
Protected left-turn phases (i.e., the provision for a specific phase for a turning
movement) significantly improve the safety for left-turn maneuvers by removing
conflicts with the opposing thru traffic. Split phases may be considered when the
geometric design of the intersection or traffic flow warrants such operation. This
provides individual phases for opposing approaches which could increase the
overall delay experienced at an intersection. However, this strategy may improve
intersection safety, as it allows conflicting movements to proceed through the
intersection independently on separate phases.
1.1.a Use Protected Left Turns
The safety problems that left-turning vehicles encounter arise from three
sources of conflict:
• Opposing through traffic,
• Through traffic in the same direction, and
• Crossing vehicular and pedestrian traffic.
These conflict types often produce left turn, angle, sideswipe same
direction, and rear-end crashes.
There are several treatments that could alleviate operational and safety
impacts of—and on—left-turn traffic. Protected left-turn phases are
warranted based on such factors as turning and opposing traffic volumes,
delay, visibility, opposing vehicle speed, and safety experience of the
intersections.
There are various options available for controlling left turns with signals:
permissive only, protected only, and permissive / protected.
The use of “permissive / protected” phasing represents a compromise
between fully protected phasing and permissive-only phasing. This
operational strategy has several advantages, the most important being the
reduction in delay for left-turning vehicles achieved by permitting left
turns while the opposing through movement has a green indication. Other
benefits include less green time needed for the protected left turn phase
(and hence more time for other high priority movements) and the potential
for improved arterial progression. The safety performance of
permissive/protected left-turn phases is not as good as that of protectedonly phases, due to the increased exposure of left-turning and opposing
through vehicles to conflicts with each other during the permissive phase.
Dual or triple left-turn lanes should only operate with protected turn
phases at four legged intersections.
The choice of lead versus lag phasing for protected left-turn phases
depends on intersection capacity and the presence of, or desire for,
coordinated system timing. Providing the left turn arrow before the
conflicting through movement receives a green indication (“lead” left
turn) minimizes the conflicts between left-turning and through vehicles.
There can be operational advantages (increased capacity) of leading left
turns if the turns are actuated and the left turn demands are unbalanced,
With a “lag” left turn phase, however, left-turning vehicles may turn left
during a permissive portion of the cycle, which may allow clearing all or
part of the left-turn queue, resulting in a shorter left turn phase or
eliminating the need for it during that specific cycle. In general, lagging
left turn strategy will cut off platoon stragglers, making platoon
movements along coordinated roadways more effective (reduced delays).
In turn, the coordinated platoon movements provide gaps for safe ingress
and egress to unsignalized side street and driveways along the coordinated
corridor.
Target- This countermeasure is targeted at reducing the number of head
on and left turn crashes associated with left-turn maneuvers involving left
turning and opposing vehicles.
1.1.b Use Split Phases
Certain geometric configurations and traffic volumes may require the use
of split phasing at an intersection. Split phasing allows opposing
movements on the same roadway to proceed through the intersection at
different times and is a way to address several geometric situations that
pose safety problems for vehicles on opposite approaches. These include
the following:
• Skewed intersections,
• Intersections with a large deflection angle for the through movement,
• Wide medians,
• Intersections with lanes shared by left-turn and through movements (i.e.,
without separate left-turn lanes),
• Intersections with significantly unbalanced opposing left-turn volumes
Split phasing targets crashes that occur related to opposing movements
proceeding on the same phase through an intersection. Crash types related
to this situation include angle, head-on left turn, rear-end-left turn, and
other rear-ends. Though studies have not conclusively proven that
implementation of split phases reduces fatalities and severe injuries at
signalized intersections, the elimination of conflicts can logically be
expected to reduce crashes.
The effectiveness in reducing crashes involving left-turning vehicles
should be similar to that of adding a protected-only left turn phase. With
no movements conflicting with vehicles on a given approach, head-on left
turn, and rear-end-left turn crashes should be eliminated.
A key to success is balancing the safety benefits of split phases with the
operational disadvantages, such as increased lost time and intersection
delay. Care should be taken to examine other potential strategies that
could provide the same safety benefit, but with less operational cost. Such
strategies might include restricting turning maneuvers, improving left-turn
channelization or construction of headed up left-turn lanes.
The use of split phasing will generally result in less efficient intersection
operations, depending on the intersection characteristics. Increasing the
number of phases usually requires a longer signal cycle and increases lost
time, resulting in longer overall intersection delay. The delay on an
approach could be increased to a point where queues will exceed available
storage lengths. This should be a factor to consider in any change of
phasing and timing. Adverse effects on arterial progression may also result
from implementation of this strategy.
Target-This strategy targets crashes related to opposing and conflicting
movements through an intersection. Crash types include sideswipes
between opposing left turns, rear ends, left turn head ons, and angles.
1.2
Optimize Clearance Intervals
The clearance interval is the portion of a signal cycle between the end of a green
phase and the beginning of the next green phase for a conflicting movement.
Clearance times provide safe, orderly transitions in right of way assignment
between conflicting streams of traffic. The clearance interval can include both
yellow and all-red time between conflicting green phases. Clearance intervals are
a function of operating speed, the width of the intersection area, lengths of
vehicles, and driver operational parameters such as reaction time, braking, and
decision-making time. MDOT has adopted ITE equation for determining the
length of the change interval.
Clearance intervals that are too short in duration can contribute to rear-end
crashes related to drivers stopping abruptly and right-angle crashes resulting from
signal violations. One study showed clearance intervals shorter than those
calculated using the ITE equation have higher rear-end and right-angle crash rates
than intersections with timings that exceed the ITE value. In the extreme, a tooshort interval can result in drivers operating at the legal speed limit being forced
to violate the red phase. A study by Retting et al. (2000) noted that signal
clearance intervals that are considered too short are associated with vehicle
conflicts and red-light running.
Lengthening clearance intervals will often require a commensurate lengthening of
the total cycle length, or decreasing the amount of green time. Clearance
intervals represent time that is lost to movement of traffic. Lengthening the cycle
reduces the percentage of time that is “lost” for clearance. Unfortunately,
widespread use of longer clearance times and cycle lengths has led in many areas
of the country to a growing problem of red-light violations. Drivers are with
greater frequency learning that the clearance time is long and that if they stop for
the signal the delay they incur will be long. MDOT has a policy for determining
clearance interval durations. See the MDOT Traffic Signal Guidance for Vehicle
Change Intervals.
Target-The target of this strategy is crashes related to clearance interval lengths
that are too short for a particular intersection. These crashes include angle
crashes between vehicles continuing through the intersection after one phase has
ended (possibly due to being in the dilemma zone as the clearance interval
started) and the vehicles entering the intersection on the following phase. Rearend crashes may also be a symptom of short clearance intervals. A vehicle
stopping at a signal may be rear ended by a vehicle following it when the
following driver expected to be able to proceed through the intersection during a
longer clearance interval.
1.3 Evaluation - Restrict or Eliminate Left or Right Turning Maneuvers
Left-turns
At signalized intersections, left-turning vehicles should have sufficient sight
distance to select gaps in oncoming traffic and complete left-turns. If this sight
distance is not available, then left-turning maneuvers should be allowed under a
protected phase only. This strategy will enhance safety at the intersection and
reduce head-on crashes associated with left-turning vehicles.
Right-turns
Regarding right-turns-on-red (RTOR), Michigan law allows this movement from
one-way or two-way streets onto a two-way street or into a one-way street
carrying traffic in the direction of the right-turn except when a sign is in place
prohibiting this turn on red. The overall impact of permitting RTOR is improved
traffic flow at all signalized intersections during on and off peak hours. A listing
of the benefits associated with RTOR is as follows:
• Reduction in fuel consumption
• Reduction in motorist delay
• Improve level of service by increasing capacity
• Reduces unnecessary delay and frustration for motorists
There are conditions that require restricting this movement in response to safety.
The guidelines that follow provide guidance to personnel in deciding when to
restrict or prohibit RTOR at a specific signalized intersection. These guidelines
take into consideration the safe movement of vehicular traffic, pedestrians,
bicyclists, and other road users while providing for efficient movement of traffic.
Each intersection approach should be evaluated on an individual basis.
Engineering judgment is the basis for each potential RTOR prohibition.
Prohibitions of RTOR, totally or in part, should be considered only when:
• Intersections have sight distance restrictions to the left that inhibit right
turns from that approach.
• More than three RTOR crashes reported in a 12-month period for the
particular approach.
• A signalized intersection with a railroad crossing (and pre-signal) in
close proximity (less than 100 feet) shall have a NO TURN ON RED if
one of the following conditions exists:
- Insufficient clear storage distance for a design vehicle between the
signalized intersection and the railroad crossing.
- The highway-rail grade crossing does not have gates.
When a RTOR is prohibited, a NO TURN ON RED sign shall be located above or
adjacent to the traffic signal or as close as possible, to the point where the turn is
made, or at both locations, so that one or more of the signs are visible to a driver
intending to turn, at the point where the turn is made, as per the “Michigan
Vehicle Code.” An additional NO TURN ON RED sign may be used at the far
side of the intersection in the direct vision of the turning driver.
August 11, 2008
Target- Prohibition of right turn on red can help reduce crashes related to limited
sight distance and those between pedestrians and right turning traffic. It can help
reduce the frequency of crashes between vehicles turning right on red and
vehicles approaching from the left on the cross street or turning left from the
opposing direction.
1.4 Coordinate Signals
Signal coordination has long been recognized as having beneficial effects on the
quality of traffic flow along a street or arterial. Good signal coordination can also
generate measurable safety benefits, primarily in two ways.
1. Coordinated signals produce platoons of vehicles that can proceed without
stopping at multiple signalized intersections. Reducing the number and frequency
of required stops and maintaining constant speeds for all vehicles reduce rear-end
and angle conflicts.
2. Signal coordination can improve the operation of turning movements. Drivers
may have difficulty making permitted turning maneuvers at signalized
intersections (e.g., permitted left turns, RTOR after stop) because of a lack of
gaps in opposing traffic of sufficient length to safely make the turns. Crashes
may occur when drivers become impatient and accept a gap that is smaller than
needed to complete a safe maneuver. Such crashes could be reduced if longer
gaps were made available. Increased platooning can create more gaps of increased
length for permitted vehicle movements at intersections and result in improved
intersection operation. Also, platooning will contribute to consistent vehicle
speeds along a corridor, which will help decrease rear-end type crashes.
Target-The target of this strategy is crashes involving major-street left-turning
and minor-street right-turning vehicles where safe gaps in opposing traffic are
not available. Rear-end crashes associated with speed changes can also be
reduced by retiming signals to promote platooning.
1.5 Improve Operation of Pedestrian and Bicycle Facilities at
Signalized Intersections
Nearly one-third of all pedestrian-related crashes occur at or within 50 feet of an
intersection. Of these, 30 percent involve a turning vehicle, whereas another 22
percent involve a pedestrian either running across the intersection or darting in
front of a vehicle whose view was blocked just prior to the impact. Another 16
6
percent of these intersection related crashes occur because of driver violation
(e.g., failure to yield the ROW).
Traffic control improvements that can be made to an intersection to increase
pedestrian safety include the following:
• Pedestrian signs, signals, and markings,
• Crossing guards for school children,
• Prohibition of right turn on red
• Public information or signs that educate pedestrians regarding use of push
buttons
Providing pedestrian push buttons may facilitate safe pedestrian roadway
crossings at signalized intersections (vs. midblock crossings), where pedestrian
conflicts with motor vehicles can be managed through use of pedestrian crossing
signals and/or exclusive pedestrian-only phases during the signal operation.
The AASHTO Guide for the Development of Bicycle Facilities should be
consulted for information on bicycle safety.
1.6 Remove Unwarranted Signals
Traffic signals can remedy many safety and operational problems at intersections.
However, signals often can adversely affect intersections. It is possible that a
signal may no longer be warranted due to changes in traffic conditions. Problems
created by an unwarranted signal, such as excessive delay, increased rerouting of
traffic to less-appropriate roads and intersections, higher crash rates, and disregard
of the traffic signal can be addressed by removing the signal if doing so would not
create worse problems. Signalized intersections generally experience crashes of
different types than unsignalized intersections but not necessarily a lower total
crash rate. Converting the intersection to unsignalized may not improve the total
crash rate. Studies should be performed when considering removing a signal, just
as installation of a signal is studied. This study should identify the appropriate
replacement traffic control devices and any sight distance restrictions that may not
have been an issue while under signalized control.
Target- Removing unwarranted signals is targeted at intersections where traffic
volumes and safety record do not warrant a traffic signal. Signalized
intersections tend to have higher rear-end crash rates than non-signalized
intersections and conversion to two-way or all-way stop control may reduce the
number of rear-end crashes.
7
2.0
Reduce Frequency and Severity of Intersection Conflicts Through Geometric
Improvements
Geometric improvements can provide both operational and safety benefits at signalized
intersections. Improvements to turning movements, through channelization or even
physically preventing turns can result in reductions in certain types of crashes. Geometric
changes can also improve safety for pedestrians and bicyclists. Higher-cost, longer-term
improvements, such as redesign of the intersection, can also improve safety and are
briefly discussed in this section.
2.1
Provide or Improve Left-Turn Channelization
This strategy includes the following:
• Providing headed up left-turn lanes,
• Lengthening left-turn lanes,
• Providing positive offset for left-turn lanes,
• Providing positive guidance with channelization, and
• Delineating turn path.
Many intersection safety problems can be traced to difficulties in accommodating
left-turning vehicles. A key strategy for minimizing collisions related to leftturning vehicles (head-on left turn, rear end left turn, angle, other rear end, and
head on crash types) is to provide exclusive left-turn lanes, particularly on highvolume and high speed major-road approaches. Left-turn lanes allow separation
of left-turn and through-traffic streams, thus reducing the potential for rear-end
collisions. Because they provide a sheltered location for drivers to wait for a gap
in opposing traffic, left-turn lanes may encourage drivers to be more selective in
choosing a gap to complete the left-turn maneuver. This may reduce the potential
for collisions between left-turn and opposing through vehicles. Provision of a leftturn lane also provides additional flexibility in designing a phasing plan.
2.1.a
Install Left-Turn Lanes
Left-turn lanes are a proven treatment for addressing safety problems
associated with left-turning vehicles. By removing left-turning vehicles
from the through traffic stream, conflicts with through vehicles traveling
in the same direction can be reduced and even eliminated, depending on
the signal timing and phasing scheme. Drivers wait in the turn lane until
there is a gap in opposing traffic through which they can turn, which helps
reduce the conflicts with the opposing through traffic. (See Traffic and
Safety Note 605a (7.6) for warranting guidelines)
2.1.b Improve Left-Turn Lane Geometry
Safety improvements can also be made to approaches that already
incorporate separate left-turn lanes. Three treatments are discussed below:
8
lengthening of the left-turn lane, redesigning to provide positive visual
offset, and delineating the turning path.
2.1.c
Lengthen Left-Turn Lane
The length of a left-turn lane consists of three components: entering taper,
deceleration length, and storage length. The left-turn lane length should
allow for the removal of slow or decelerating vehicles from through
traffic, thus reducing the potential for rear-end collisions. A turn lane long
enough to accommodate deceleration can have safety benefits for higherspeed intersections such as are typically found on rural highways. The turn
lane should be of adequate length to store vehicles waiting to turn left
without the queue overflowing into the adjacent through lane. If a left-turn
queue extends into the adjacent through lane, through vehicles will be
forced to stop or, if there are multiple through lanes, change lanes. These
maneuvers can lead to rear-end and sideswipe crashes. Design criteria for
selecting an appropriate left-turn lane length are presented in the
AASHTO Policy on Geometric Design for Highways and Streets
(American Association of State Highway and Transportation Officials).
Geometric Design Guide VII-650 Series has recommended taper and
storage lengths.
2.1.d Provide Positive Offset for Left-Turn Lanes
A potential for conflict exists when vehicles in opposing turn lanes on the
major road block the drivers’ views of approaching traffic. A left turning
driver’s view of opposing through traffic may be blocked by left-turning
vehicles on the opposite approach. When left-turning traffic has a
permissive green signal phase, this can lead to collisions between vehicles
turning left and the through vehicles on the opposing road approach. To
reduce the potential for crashes of this type, the left-turn lanes can be
offset by moving them laterally, so that vehicles in opposing left turn lanes
no longer obstruct the view of the opposing through traffic. This helps
improve safety and operations of the left-turn movement by improving
driver acceptance of gaps in opposing through traffic. This is especially
true for older drivers who have difficulty judging gaps between oncoming
vehicles.
Note that the effectiveness of this strategy is greatest where signal
operations include permissive signal phasing or permissive/protected
phasing for left-turning movements. AASHTO’s Policy recommends that
medians wider than 18 feet should have offset left-turn lanes. One method
for laterally shifting left-turning vehicles is to narrow the turn lane width
using pavement markings. This is accomplished by painting a wider stripe
at the right side of the left-turn lane, which causes left-turning vehicles to
position themselves closer to the median. The width of these lines ranged
9
from 0.5 feet to 3 feet. The wider the left turn lane line used to offset
vehicles, the greater the effect on improving sight distance.
2.1.e
Delineate Turn Path
Even at signalized intersections, where the traffic signals help to eliminate
confusion about ROW, driver confusion can exist in regard to choosing
the proper turn path. This is especially relevant at intersections where
multiple left-turn lanes are provided, the overall pavement area of the
intersection is large, or other unfamiliar elements are presented to the
driver. Delineation of turn paths is especially useful to drivers making
simultaneous opposing left turns, as well as some cases involving drivers
turning right for which a clear path is not readily apparent. This strategy is
also appropriate for application where the roadway alignment may be
confusing or unusual, such as a deviation in the path for through vehicles.
Providing positive guidance to the driver in the form of pavement
markings can help eliminate driver confusion and eliminate vehicle
conflict by “channeling” vehicles in their proper path.
Target- These strategies target intersections where crashes related to leftturn movements are an issue. Crash types that could be reduced include
angle, sideswipe, rear-end, and head-on crashes.
2.1.f
Four-Lane to Three-Lane Conversion
See Guidelines for Four-Lane to Three-Lane Conversions by Michigan
State University.
2.2
Provide or Improve Right-Turn Lanes
This strategy includes the following:
• Providing right-turn lanes,
• Lengthening right-turn lanes
The provision of right-turn lanes can minimize collisions between vehicles
turning right and following vehicles, particularly on high-volume and high-speed
major roads. See Traffic and Safety Note 604 (7.5).
2.2.a
Construct Right Turn Lanes
A right-turn lane may be appropriate in situations where there are an
unusually high number of rear-end collisions on a particular approach.
Installation of a right-turn lane on one major road approach at a signalized
intersection is expected to reduce total crashes.
It is possible that installation of a right-turn lane could create other safety
or operational problems at the intersection. For example, vehicles in the
10
right-turn lane may block the cross street right-turning drivers’ view of
through traffic; this would be a significant issue where RTOR are
permitted on the cross street. If a right shoulder is re-striped to provide a
turn lane, there may be an adverse effect on safety due to the decrease in
distance to roadside objects. Delineation of the turn lane also should be
carefully considered, so that adequate guidance is provided through the
intersection. Right-turn roadways can reduce the safety of pedestrian
crossings. Crossing distances are increased, as is pedestrian exposure to
traffic. Elderly and mobility-impaired pedestrians may have difficulty
crossing intersections with large corner radii.
2.2.b Lengthen Right-Turn Lanes
Lengthening a right-turn lane can help improve operations and safety by
providing additional sheltered space for vehicles to decelerate or wait to
turn. If the length of a right-turn lane is inadequate, vehicles waiting to
turn may be doing so from the through-traffic stream, thus increasing the
potential for rear-end collisions. Providing longer entering tapers and
deceleration lengths can reduce the potential for rear-enders. Also, if
access to a right-turn lane is blocked by a queue of through vehicles at a
signal, the right-turners may block the movement of through traffic, if the
two movements operate on separate or split phases. This could lead to
unsafe lane changes and added delay. The length of a right-turn lane
consists of three components: entering taper, deceleration length, and
storage length. Design criteria for selecting an appropriate right-turn lane
length are presented in both the AASHTO Policy on Geometric Design for
Highways and Streets and the TRB Highway Capacity Manual, as well as
in the MDOT Geometric Design Guide VII-650.
Ensure proper pavement marking (such as right turn arrows) and signing
(such as Right Lane Must Turn Right) so a lengthened right turn lane is
not confused for another thru lane.
3.0
Improve Geometry of Pedestrian, Bicycle, and Transit Facilities
The mix of travel modes at intersections, along with the vehicle-vehicle conflicts
possible, can create safety and operational concerns for non-motorists. A variety of
relatively low-cost treatments can be implemented to help pedestrians and bicyclists
proceed through the intersection more safely and more efficiently. Multi-vehicle crashes
(specifically rear-ends) can be reduced if pedestrians are more visible and more drivers
expect to encounter them. Geometric or physical improvements that can be made to an
intersection to increase pedestrian safety include the provision of the following:
• Continuous sidewalks,
• Signed and marked crosswalks,
• ADA compliant sidewalk ramps,
11
• Sidewalk set-backs,
• Median refuge areas,
• Bulb-outs,
• Pedestrian overpasses,
• Intersection lighting,
• Physical barriers to restrict pedestrian crossing maneuvers at higher-risk locations,
• Relocation of transit stops from the near side to the far side of the intersection, and
• Other traffic calming applications to reduce vehicle speeds or traffic volumes on
intersection approaches.
Improvements to pedestrian facilities are discussed in greater detail in Volume 10 of the
NCHRP Report 500, “A Guide for Reducing Collisions Involving Pedestrians”. Some of
the problems facing bicyclists at intersections include high traffic volumes and speeds as
well as the lack of space for bikes. Possible improvement projects include the following:
• Widening outside through lanes (or adding bike lanes),
• Providing median refuge areas,
• Providing independent crossing structures,
• Upgrading storm drain grates with bicycle-safe designs, and
• Implementing lighting.
Also refer to the AASHTO Guide for Non-Motorized Facilities.
The demand for bus service is largely a function of land-use patterns. The general
location of bus stops is largely dictated by patronage and by the locations of intersection
bus routes and transfer points. Bus stops at intersections may be located on the near
(approach) or far (departure) side of the intersection.
Far-side bus stops are advantageous at intersections where:
• Other buses may turn left or right from the arterial
• Turning movements from the arterial by other vehicle types, particularly right
turns are heavy
• Approach volumes are heavy, creating a large demand for vehicle storage on the
near-side approach
Far-side bus stops are also effective at reducing collisions involving pedestrians. Sight
distance conditions generally favor far-side bus stops, especially at signalized
intersections.
The interference between buses and other traffic can be considerably reduced by
providing bus turnouts (stops clear of the through lanes). However, since bus operators
may not use the turnout if they have difficulty maneuvering back into traffic, the bus
turnout should be designed so that a bus can enter and leave easily.
Refer to the AASHTO Policy on Geometric Design of Highways and Streets for more
information regarding transit facilities.
12
4.0
Revise Geometry of Complex Intersections
This strategy includes a series of mostly higher-cost solutions:
• Converting a four-leg intersection to two T intersections,
• Converting two T intersections to one four-leg intersection,
• Improving intersection skew angle, and
• Improving deflection in the through-vehicle travel path.
A fifth solution, closing an intersection leg, is one commonly tried when addressing the
problem of complex intersections. This can be a low-cost solution because it does not
typically require major reconstruction. Making one approach one-way away can also
decrease conflicts. Some geometric problems with signalized intersections will not be
remedied using signing, channelization, or signal phasing. Physical modifications to all or
part of an intersection may be needed to reduce severe crash rates. There may be multiple
problems associated with one or more movements at the intersection that can be best
addressed with significant improvements to intersection design.
4.1
Convert One Four-Leg Intersection to Two T-Intersections
For some signalized four-leg intersections with very low through volumes on the
cross street, the best method of improving safety may be to convert the
intersection to two T intersections. This strategy should help reduce crashes
related to the intersection layout, such as angle crashes involving left-turning
vehicles in which drivers are not expecting to encounter one of the infrequent
through-vehicles. This conversion to two T intersections can be accomplished by
realigning the two cross-street approaches an appreciable distance along the major
road, thus creating separate intersections that operate relatively independently of
one another. The intersections should be separated enough to ensure the provision
of adequate turn-lane channelization on the major road to prevent left turns
interlocking. If through volumes are high, the intersection may be safer if left as a
conventional four-leg intersection. Converting it to two T intersections would
only create excessive turning movements at each of the T intersections. In a study
conducted by Hanna et al., (1976) offset intersections had accident rates that were
approximately 43 percent of the crash rate at comparable four-leg intersections.
Thus, it is expected that this strategy would reduce the crash experience of
targeted four-leg intersections. (See Geometric Design Guide GEO-640 Series)
13
Type 3a: Provide sufficient storage distance
between the two intersections to prevent
interlocking of the left-turns on the trunkline
(Note: Type 3a should be used only when
Type 3 is not possible).
Trunkline
Type 3: For use where crossroad
has light through traffic. This
design eliminates interlocking
left-turns on the trunkline.
Crossroad
Trunkline
Crossroad
4.2
Convert Two T-Intersections to One Four-Leg Intersection
For some signalized offset T intersections with very high through volumes on the
cross street, the best method for improving safety may be to convert the
intersection to a single four-leg intersection. This can be accomplished by
realigning the two cross-street approaches to meet at a single point along the
major road. It is expected that this strategy would reduce crashes involving leftturning traffic from the major road onto the cross street at each of the two T
intersections.
4.3
Improve Intersection Skew Angle
Roads that intersect with each other at angles less than 90 degrees can present
sight distance and operational problems for drivers. A high incidence of rightangle accidents, particularly involving vehicles approaching from the acute angle,
may be the result of a problem associated with skew. Vehicles have a longer
distance to travel through the intersection (increasing their exposure to conflicts),
and drivers may find it difficult to turn their head and neck to view an approach
on an acute angle. Furthermore, vehicles turning right at an acute angle may
encroach on the lane for vehicles approaching from the opposite direction. When
RTOR are permitted, drivers may have more difficulty judging gaps when
turning. Also, crossing distances for pedestrians are increased. Skewed
intersections (with the angle of intersection less than 75 degrees) pose particular
problems for older drivers, as many older drivers experience a decline in head and
neck mobility. A restricted range of motion reduces the older driver’s ability to
effectively scan to the rear and sides of their vehicle to observe blind spots. They
may also have trouble identifying gaps in traffic when making a left turn or safely
merging with traffic when making a right turn. (See Geometric Design Guide
GEO-640 Series)
14
4.4
Remove Deflection in Through-Vehicle Travel Path
Intersections with substantial deflections between approach alignments can
produce operational and safety problems for through-vehicles as they navigate
through an intersection. Forced path changes for through-vehicles violate driver
expectations and may be difficult for unfamiliar drivers to navigate. Violation of
driver expectancy can result in reduced speed of the vehicle through the
intersection. Crashes influenced by a deflection in travel path are likely to include
rear-end, sideswipe, and head-on. Acceptable deflection angles through
intersections vary by individual agency, but are typically related to the design
and/or posted speed on an intersection approach. Typical maximum deflection
angles are 3 to 5 degrees. The use of curves is preferable to deflections.
Pavement markings can be a low-cost solution to guide through vehicles through
the intersection. Dashed lines similar to those used to delineate left-turn paths are
appropriate for delineation of the through path. Redesign of an intersection
approach is a relatively high-cost solution. Proper design of an intersection
involves providing traffic lanes that are clearly visible to drivers at all times,
clearly understandable for any desired direction of travel, free from the potential
for conflicts to appear suddenly, and consistent in design with the portions of the
highway approaching the intersection.
4.5
Close Intersection Leg
For some signalized intersections with crash histories, the best method for
improving safety may be to close access to a leg of the intersection. This may be
an unpopular approach to safety improvement that should generally be considered
only when less restrictive measures have been tried and have failed. Closure of
access to an intersection leg can be accomplished by closing and abandoning a
minor approach using channelizing devices or by reconstructing the minor
approach so that it dead-ends before reaching the intersection with the major
street. An alternative to closing the entire intersection leg is to convert the leg to a
one-way street that departs the intersection. Though it is a significant modification
to an intersection, it can be a low-cost treatment. A major consideration in
deciding to implement this strategy is the impact closure will have on traffic
patterns and volumes at other locations. This treatment may be most applicable to
those intersections with more than four legs.
Target- Signalized intersections with high levels of crashes on a leg where other
strategies have not been successful or are not considered appropriate. Any crash
type could be targeted since reasons for closing at intersections leg can vary.
5.0 Construct Special Solutions
This strategy includes the following:
• Providing indirect left turn,
• Reconstructing intersections, converting intersections to roundabouts,
15
• Convert two-way streets to a one-way pair, and
• Constructing interchanges.
Signalized intersections may have such a significant crash problem that the only
alternative is to change the nature of the intersection itself. These types of projects will be
higher cost and require substantial time for implementation.
5.1
Provide Indirect Left Turns
As traffic growth on arterial roadways continues to result in congestion and safety
problems at major (high-volume) at-grade intersections, indirect left turn designs
are increasingly being considered and constructed. A few indirect left-turn
designs are relatively common to some areas, while many involve rather
innovative solutions.
Safety problems associated with left-turns at major signalized intersections are
magnified at high-volume intersections—or, at least, intersections with high
volumes of left turns. Indirect left-turn treatments, such as jughandles before the
crossroad, directional median crossovers, and loop roadways beyond the
crossroad, can address both safety and operational problems related to left turns
by eliminating them at the crossroad intersections.
These treatments also remove the left turning vehicles from the traffic stream
without causing them to stop in a through-traffic lane, thereby reducing the
potential for rear-end crashes with through vehicles. This strategy should also
reduce right-angle collisions resulting from the conflict between vehicles turning
left and oncoming through-vehicles.
5.2
Convert Two-Way Streets to a One-Way Pair
When two-way streets are converted to one-way streets, it is generally for the
purpose of increasing capacity, but the removal of opposing traffic flows can
improve safety as well. Removal of one direction of traffic from a two-way street
allows for better signal synchronization and progression of platoons. Smooth
progression and reduced congestion can reduce rear-end crashes. In addition, the
removal of one direction of traffic can reduce congestion and improve safety by:
• Reducing the number of vehicle/vehicle conflict points at intersections,
• Allowing for unopposed turn maneuvers,
• Simplifying operations and signal phasing,
• Allowing pedestrians to only have to deal with traffic from one direction,
reducing conflicts with vehicles, and
• Providing more gaps for vehicles and pedestrians at unsignalized crossings.
The ITE Traffic Safety Toolbox (Institute of Transportation Engineers, 1999)
reports that studies have shown a 10- to 50-percent reduction in total crashes after
conversion of a two way street to one-way operation. At the same time, this
16
strategy increases capacity significantly; a one-way street pair can handle up to 50
percent more volume than two parallel two-way streets.
6.0
Improve Sight Distance at Signalized Intersections
Adequate intersection sight distance contributes to the safety of the intersection. In
general, sight distance is needed at signalized intersections for the first vehicle stopped at
an approach to be able to see the first vehicles stopped at the other approaches, for drivers
making permitted left turns, and for right-turning vehicles. Where RTOR are allowed,
adequate sight distance should be available. It should also be available for signals that
have flash schedules in off peak hours. Improvements in sight distance can lead to a
reduction in crashes caused by drivers stopping suddenly (rear-end), drivers proceeding
through the intersection when the signal has not assigned them the right-of-way (angle),
and drivers turning through an inadequate gap in opposing traffic (angle).
6.1
Clear Sight Triangles
Sight distance improvements can often be achieved at relatively low cost by
clearing sight triangles to restore sight distance obstructed by vegetation, roadside
appurtenances, buildings, bus stops, parked cars, or other natural or man-made
objects.
Research has established a relationship between intersection safety and sight
distance at unsignalized intersections. No such research quantifies the
effectiveness of improving sight distance at signalized intersections. One may
expect that crashes related to inadequate sight distance (specifically, angle and
turning related) would be reduced if the sight distance problems are improved.
However, as the signal assigns ROW for most vehicles crossing paths at right
angles and because traffic volumes affected by the other situations cited above are
low, the overall impact on crashes could be relatively small.
6.2
Redesign Intersection Approaches
Signalized intersections with sight-distance-related safety problems that cannot be
addressed with less expensive methods (such as clearing sight triangles, adjusting
signal phasing, or prohibiting turning movements) may require horizontal or
vertical (or both) realignment of approaches. Realigning both of the minor-road
approaches so that they intersect the major road at a different location, or a
different angle, can help address horizontal sight distance issues. This is a highcost, longer-term treatment for the intersection, but if completed according to
applicable design policy, it should help alleviate crashes related to sight distance.
The current AASHTO Policy on Geometric Design of Highways and Streets
contains updated sight distance guidelines, and these guidelines should be
considered when revising intersection approach geometry. Intersection relocation
and closure, elimination of intersection skew, and offsetting of left turn lanes are
17
all strategies that involve improvements to approach alignment to improve sight
distance.
7.0
Improve Driver Awareness of Intersections and Signal Control
Driver awareness of both downstream intersections and traffic control devices is critical
to intersection safety. The inability to perceive an intersection or its control or the back of
a stopped queue in time to react as necessary can result in safety problems. Drivers
caught unaware could be involved in serious crashes, especially at intersections with high
speeds on the approaches. This objective details strategies aimed at improving driver
awareness of signalized intersections and the traffic control in place.
7.1
Improve Visibility of Intersections on Approaches
This strategy includes the following:
• Improving signing and delineation,
• Installing larger signs, and signal heads
• Providing intersection lighting,
• Installing rumble strips on approaches,
• Installing queue detection system, and
• Supplemental flasher on advance warning signs.
Some crashes at signalized intersections may occur because drivers are unaware
of the presence of an intersection or are unable to see the traffic signals in time to
comply. These crashes are generally rear-end or angle collisions. The ability of
approaching drivers to perceive signalized intersections immediately downstream
can be enhanced by signing, delineation, and active warning devices. Other
strategies to improve the visibility of an intersection include providing lighting,
improving the visibility of the signals, and using devices to call attention to the
signals. The FHWA report Synthesis of Human Factors Research on Older
Drivers and Highway Safety: Volume 2 (Staplin et al., 1997) reviews research on
older drivers’ visual abilities related to driving. Research shows that recognition
and legibility distances as well as response speeds are lower for older drivers than
for younger ones. The Synthesis summarizes recent research by stating that if
recognition of an intersection is based on signs being legible to drivers, older
drivers will take longer to recognize intersections. Therefore, consideration
should be given to providing traffic control devices that contribute to improved
legibility and response times for older drivers. This may include redundant
signing, overhead signing, and advanced route signing. The older drivers guide
should be consulted for more information.
7.2
Improve Signing and Delineation
Installing or upgrading signs and pavement markings on intersection approaches
can help better prepare drivers for the intersection ahead. This may include
advance guide signs, advance street name signs, warning signs, pavement
18
markings, overhead street signing, and post-mounted delineators. Advance
warning signs, such as the standard intersection warning sign or the standard sign
with flashers, can also alert drivers to the presence of an intersection. Installing
advance warning signs on both sides of the roadway to provide redundancy in
signing may be appropriate in some situations, such as when the intersection
approach is on a curve. Street name and lane assignment signs in advance of the
intersection prepare drivers for choosing and moving into the lane they will need
to use for their desired maneuver.
7.3
Install Larger Signs
The visibility of intersections with existing regulatory and warning signs and the
ability of drivers to perceive the signs can be enhanced by installing larger signs
with larger letters. Such improvements may include advance guide signs, warning
signs, pavement markings, and post-mounted delineators.
7.4
Provide Intersection Lighting
Providing lighting at the intersection itself or at both the intersection and on its
approaches can make drivers aware of the presence of the intersection and reduce
nighttime crashes. Crash data should be studied to ensure that safety at the
intersection could be improved by providing lighting (this strategy would be
supported by a significant number of crashes that occur at night). The costs
involved with intersection lighting are the responsibility of the local jurisdiction.
7.5
Install Rumble Strips on Approaches
Rumble strips can be installed on the roadway on intersection approaches
transverse to the direction of travel to call attention to the presence of the
intersection and the traffic control used. Rumble strips are particularly appropriate
on intersections where a pattern of crashes related to lack of driver recognition of
the presence of the signal is evident, often on high-speed approaches. This
strategy should be used sparingly, as the effectiveness of rumble strips is
dependent on their being unusual. Rumble strips are normally applied when less
intrusive measures, such as “signal ahead” signs or flashers, have been tried and
have failed to correct the crash pattern, and they are typically used in combination
with the advance warning signs. Care must be taken to avoid use of rumble strips
where the noise generated will be disturbing to adjacent properties. See Traffic
and Safety Note 609B (7.11).
7.6
Install Queue Detection System
Queue detection systems are standard tools for operation of traffic signals. In
normal practice, queue detection is used for actuated signal systems to “call-up” a
phase given the presence of a vehicle in a specific lane or movement. The
application of queue detection systems as safety devices is a new and potentially
19
effective device. One such system has been implemented in Oregon on an
approach to a signalized intersection in a rural setting that regularly experiences
significant queues, especially during the summer when seasonal traffic increases.
Two loop detectors in each lane on the intersection approach detect when a
vehicle is stopped at that location. The detectors are connected to an overhead
sign with beacons located a half mile upstream. The sign contains the message
“Prepare to stop when lights flash.” When a vehicle is continuously present at a
detector, beacons on the overhead sign flash to warn drivers of the stopped
vehicle ahead. A preliminary evaluation indicates a reduction in crashes after
installation of this system, but additional data are needed to determine if other
factors contributed to this decrease.
7.7
Improve Visibility of Signals and Signs at Intersections
Lack of visibility of traffic control devices may contribute to crash experience at
signalized intersections. Visibility of traffic signals and signs at intersections may
be obstructed by physical objects (such as signs or other vehicles) or may be
obscured by weather conditions, such as fog or bright sunlight. Also, drivers’
attention may be focused on other objects at the intersection, such as extraneous
signs. Poor visibility of signs and signals may result in vehicles not being able to
stop in time for a signal change or otherwise violating the intended message of a
regulatory or directional sign. Providing adequate visibility of signs and signals
also aids in drivers’ advance perception of the upcoming intersection. The FHWA
Older Driver Highway Design Handbook should be consulted to ensure that
improvements to visibility of traffic control devices will be adequate for older
drivers. Methods for improving visibility of traffic signals and signs include the
following:
• Install additional signal head,
• Provide visors to shade signal lenses from sunlight,
• Provide louvers, visors, or special lenses so drivers are able to view signals only
for their approach,
• Remove trees and street hardware that restrict visibility to signals,
• Install larger (12-in.) signal lenses,
• Remove or relocate unnecessary signs, and
• Provide far-side left-turn signal.
Target- These strategies are targeted at crashes that occur because drivers are
unable to see traffic signals and signs sufficiently in advance to safely negotiate
the approaching intersection. Crash types would include angle and rear-end
crashes.
8.0
Improve Access Management Near Signalized Intersections
Effective access management is a key to improving safety at, and adjacent to,
intersections. The number of access points, coupled with the speed differential between
vehicles traveling along the roadway and vehicles using driveways, contributes to rear-
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end crashes. The AASHTO Policy on Geometric Design states that driveways should not
be located within the functional area of an intersection. The ITE Traffic Engineering
Handbook suggests that the functional area include storage lengths for turning
movements and space to maneuver into turn lanes, and consideration should be given to
locating driveways, so as to provide enough space to store queues ahead of or behind
driveways. Closing or relocating driveways will reduce turning movements near
intersections. Prohibiting turn movements is another strategy to address access
management at intersections.
8.1
Restrict Access to Properties Using Driveway Closures or Turn
Restrictions
Restricting access to commercial properties near intersections by closing
driveways on major streets, moving them to cross streets, or restricting turns into
and out of driveways will help reduce conflicts between through and turning
traffic. Such conflicts can lead to rear-end and angle crashes related to vehicles
turning into and out of driveways and speed changes near the intersection and the
driveway(s). Locations of driveways on both the cross street and major street
should be determined based on the probability that a queue at the signal will block
the driveway. Directing vehicles to exits on signalized cross streets will help
eliminate or restrict the access to the main roadway. Restricting turns to rights-in
and rights-out only will address conflicts involving vehicles turning left from the
road and left from the driveway.
8.2
Restrict Cross-Median Access near Intersections
When a median opening on a high-volume street is near a signalized intersection,
it may be appropriate to restrict cross-median access for adjacent driveways. For
example, left and U-turns can be prohibited from the through traffic stream, and
left turns from adjacent driveways can be eliminated. Restrictions can be
implemented by signing, by redesign of driveway channelization, or by closing
the median access point via raised channelization, and constructing U-turn
directional crossovers per MDOT spacing requirements.
Target- The target of this strategy is crashes involving drivers making turns
across medians on approaches to signalized intersections. Angle crashes between
vehicles turning through the median and opposing vehicles, as well as rear-end
crashes involving vehicles waiting to turn and following vehicles, are crashes
related to the cross median movement. Sideswipe crashes may occur when a
following vehicle on the major road attempts to pass a vehicle waiting to turn left
through the median. Restricting cross-median access is expected to eliminate
conflicts related to vehicles using the median opening, as well as related rear-end
and angle crashes.
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9.0
Improve Safety Through Other Infrastructure Treatments
Safety problems at signalized intersections may not be specifically related to traffic
control, geometry, enforcement, or driver awareness of the intersection. This section
provides information on strategies for special intersection conditions that were not
covered in the objectives above.
9.1
Improve Drainage in Intersection and on Approaches
One of the most important principles of good highway design is drainage.
Drainage problems on approaches to and within intersections can contribute to
crashes just as they can on roadway sections between intersections. However,
within an intersection, the potential for vehicles on cross streets being involved in
crashes contributes to the likelihood for severe crashes, specifically angle crashes.
It is necessary to intercept concentrated storm water at all intersection locations
before it reaches the highway and to remove over-the-curb flow and surface water
without interrupting traffic flow or causing a problem for vehicle occupants,
pedestrians, or bicyclists.
The target for this strategy is crashes at signalized intersections that are related to
poor drainage. Such crashes involve vehicles that hydroplane and hence are not
able to stop when required; these crash types include angle, rear end, and head on.
Pedestrians and bicyclists would also be at risk. Improved drainage can help
improve safety, increase traffic capacity, and increase the load capacity of the
pavement. However, no adequate documentation of the effect on crash experience
seems to be published. It can be expected that improved drainage would reduce
crashes related to hydroplaning and wet crashes.
9.2
Provide Skid Resistance in Intersection and on Approaches
Slippery pavement should be addressed to reduce the potential for skidding. The
coefficient of friction is most influenced by vehicle speed, vehicle tire condition,
and road surface condition. Consideration should be given to improving the
pavement condition to provide good skid resistance, especially during wet
weather. This can be accomplished by:
• Providing adequate drainage,
• Grooving existing pavement,
• Overlaying existing pavement, and
• Grinding concrete pavement.
9.3
Restrict or Eliminate Parking on Intersection Approaches
Parking adjacent to turning and/or through lanes on intersection approaches may
create a safety issue. It can cause a frictional effect on the through traffic stream,
can often block the sight triangle of stopped vehicles, and may occasionally cause
the blocking of traffic lanes as vehicles move into and out of parking spaces.
22
Restricting and/or eliminating parking on intersection approaches can improve
visibility for the driver and limit additional collision opportunities. Parking
restrictions can be implemented through signing, pavement markings, or
restrictive channelization. Restrictions can be implemented for specific times of
day or specific vehicle types. Enforcement of parking restrictions, accompanied
by public information, including towing offending vehicles, is a necessary
component to this strategy.
This strategy targets crashes related to parking on intersection approaches. The
parking, though currently permitted, may present a safety issue by restricting sight
distance (and contributing to angle crashes) or due to parking maneuvers
(contributing to rear-end and sideswipe crashes). On-street parking can decrease
pedestrian safety if parked vehicles block drivers’ and pedestrians’ views of each
other. Curb extension (bump out) can be constructed where pedestrians cross
streets, and parking should not be permitted on approaches to crosswalks. Further
information on this aspect of the problem is covered in the pedestrian crash guide
(NCHRP Report 500: Guidance for Implementation for the ASHTO Strategic
Highway Safety Plan, Volume 10: A Guide for Reducing Collisions Involving
Pedestrians).
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Strategies to Improve Safety and Operations at
Unsignalized Intersections
The strategies for improving safety at unsignalized intersections are directed at the
physical improvement of the intersections and their approaches. The improvements
considered include geometric design modifications and changes to traffic control devices.
1.0 Improve Access Management Near Unsignalized Intersections
Refer to MDOT’s The Access Management Guidelines.
1.1
Implement Driveway Closures/Relocations
Effective access management is key to improving safety at and adjacent to
unsignalized intersections. A key element of access management is closure or
relocation of driveways adjacent to intersections. Access points less than the
recommended distances in Traffic and Safety Note 608 (7.9) upstream and
downstream of an intersection are generally undesirable. Strategies for mitigating
safety problems that may arise from a driveway located too close to an
unsignalized intersection are to close the driveway (if other access to the property
already exists) or to relocate the driveway (if no other appropriate access is
available). It is desirable to relocate access points on the major-road approach to
an intersection, to the minor-road approach (away from the intersection), or
(where practical) to another street or frontage road. Where there is access from
the minor road, from a side street, or from a frontage road, relocating the
driveway on the major road farther from the intersection may be considered.
Target- Unsignalized intersections with high crash frequencies related to
driveways adjacent to the intersection. Generally, driveways within 250 feet of
the intersection are considered closer than optimum.
1.2
Implement Driveway Turn Restrictions
When a driveway on a high-volume street adjacent to an unsignalized intersection
cannot be closed or relocated, it may be appropriate to restrict turning maneuvers
at the driveway. For example, left turns at the driveway can be restricted and
driveway movements limited to right turns in and right turns out. See Traffic and
Safety Note 603A (7.3). In other cases, turning movements into a property may
be permitted at a particular driveway, but turning movements out of the property
may be diverted to a different driveway. Furthermore, driveway usage may be
restricted at particularly critical times of the day. Such restrictions can be
implemented by signing. Other methods of restricting turning movements can be
accomplished by channelizing islands where the driveway enters the major street,
by redesign of internal circulation patterns within a property, by provision of a
median on the major street, or by a combination of these approaches. Restricting
24
turning movements through signage is only marginally effective, physical
restrictions (such as channelizing islands) are preferred, when possible.
Target- Driveways located near unsignalized intersections that experience high
crash frequencies but cannot practically be closed or relocated.
2.0
Reduce the Frequency and Severity of Conflicts Through Geometric
Improvements
2.1
Provide Left-Turn Lanes at Intersections
Left-turn lanes remove vehicles waiting to turn left from the through traffic lane,
thus reducing the potential for rear-end collisions. Left turn lanes provided a
sheltered location for drivers to wait for a gap in opposing traffic, encouraging
drivers to be more selective picking a gap to complete their left turn maneuver.
Design criteria for left-turn lanes are presented in the AASHTO Policy on
Geometric Design for Highways and Streets, and Geometric Design Guide VII650. Traffic volume guidelines for the installation of left turn lanes are found in
Traffic and Safety Note 605 (7.6).
Target- Reduce the frequency of crashes resulting from the conflict between (1)
vehicles turning left and following vehicles and (2) vehicles turning left and
opposing through vehicles.
2.2
Provide Longer Left-Turn Lanes at Intersections
The length of a left-turn lane is among its most important design elements. Leftturn lanes should be designed to accommodate vehicle deceleration and storage.
In particular, the left turn lane length should allow for the removal of slow or
decelerating vehicles from through traffic, thus reducing the potential for rear-end
collisions. The length of a left-turn lane consists of three components: (1) entering
taper, (2) deceleration length, and (3) storage length. Design criteria for selecting
an appropriate left-turn lane length are presented in the AASHTO Policy on
Geometric Design for Highways and Streets, and Geometric Design Guide VII650.
Target- This countermeasure is targeted to reduce the frequency of rear-end
collisions between through traffic and left turning vehicles queued up in through
lanes due to insufficient storage.
2.3
Provide Offset Left-Turn Lanes at Intersections
A potential problem in installing left-turn lanes at intersections is that vehicles in
opposing turn lanes on the road may block drivers’ views of approaching traffic.
This can lead to collisions between vehicles turning left from the major road and
through vehicles on the opposing major-road approach. To reduce the potential
25
for crashes of this type, the left-turn lanes can be offset by moving them laterally
so that vehicles in opposing lanes no longer obstruct the opposing driver. Two
treatments for offsetting turn lanes are parallel and tapered offset left-turn lanes.
These treatments are addressed in the AASHTO Policy on Geometric Design of
Highways and Streets. While offset left-turn lanes have been used most
extensively at signalized intersections, they are suitable for use at unsignalized
intersections as well.
Target- Off set left-turn lanes, with the inherent improvement in sight distance,
helps reduce the frequency of collisions between vehicles turning left and
opposing through vehicles particularly in the median of divided highways.
2.4
Provide Passing Flares on Shoulders at T-Intersections
At three-legged intersections on two-lane highways, passing flares can provide an
effective substitute for a left-turn lane on the major road where provision of a leftturn lane is economically infeasible. Instead of providing a left-turn lane for
drivers turning left from the major road, part of the shoulder may be marked as a
passing flare to encourage through drivers to use this lane to pass vehicles waiting
to turn left. This treatment involves substantially less cost than providing a
conventional left-turn lane and, at low-volume intersections, it may be just as
effective. See Geometric Design Guide VII-650. Traffic volume guidelines for
the installation of by-pass lanes are found in Traffic and Safety Note 605 (7.6).
Target- Intersections that have a pattern of rear-end collisions involving vehicles
waiting to turn left from the highway.
2.5
Provide Right-Turn Lanes at Intersections
Many collisions at unsignalized intersections are related to right-turn maneuvers.
A key strategy for minimizing such collisions is to provide exclusive right-turn
lanes, particularly on high-volume and high-speed major-road approaches. Rightturn lanes remove slow vehicles that are decelerating to turn right from the
through-traffic stream, thus reducing the potential for rear-end collisions. See
Geometric Design Guide VII-650. Traffic volume guidelines are found in Traffic
and Safety Note 604 (7.5).
Target- Intersections that have a pattern of rear-end collisions involving vehicles
turning right from the highway and following vehicles.
2.6
Provide Longer Right-Turn Lanes at Intersections
The provision of exclusive right-turn lanes minimizes collisions related to rightturn maneuvers, particularly on high-volume and high-speed major roads.
However, if the length of a right-turn lane is inadequate, vehicles waiting to turn
may be doing so from the through-traffic lane, thus increasing the potential for
26
rear-end collisions. If long enough, right-turn lanes provide sheltered locations for
drivers decelerating or waiting to make a right turn maneuver. The length of a
right-turn lane consists of three components: (1) entering taper, (2) deceleration
length, and (3) storage length. Design criteria for selecting an appropriate rightturn lane length are presented in the AASHTO Policy on Geometric Design for
Highways and Streets.
Target- Intersections that have a pattern of rear-end collisions involving vehicles
waiting to turn right from the highway and following vehicles.
2.7
Provide Offset Right-Turn Lanes at Intersections
A potential problem in installing right-turn lanes at intersections is that vehicles in
the right turn lane on the major road may block the minor-road drivers’ views of
traffic approaching on the major road. This can lead to collisions between
vehicles turning left, turning right, or crossing from the minor road and through
vehicles on the major road. To reduce the potential for crashes of this type, the
right-turn lanes can be offset by moving them laterally so that vehicles in the
right-turn lanes no longer obstruct the view of the minor-road driver.
Target- Reduce the frequency of crashes between vehicles from the cross street
and through vehicles by improving the intersection sight distance.
2.8
Provide Full-Width Paved Shoulders in Intersection Areas
Well-designed and properly maintained shoulders in intersection areas provide
• Space for the motorist to avoid potential crashes or reduce crash severity,
• Improved lateral placement of vehicles and space for encroachment of
vehicles,
• Space for pedestrian and bicycle use, and
• Space to park disabled vehicles out of the traveled way.
Full-width shoulders can be used for temporary storage of snow that is plowed
from the road during times of heavy snowfall, allowing the full width of the lanes
to be available for moving traffic and minimizing the potential sight obstruction
of plowed snow.
Target- Unsignalized intersections, particularly on divided highways, with
shoulders less 8 feet in width that experience a high number of run off the road
crashes as a result of avoidance maneuvers, or a high number of rear-end crashes
that may have been avoided had a full width shoulder been provided.
2.9
Restrict or Eliminate Turning Maneuvers by Signing
Safety at some unsignalized intersections can be enhanced by restricting turning
maneuvers, particularly left turns, during certain periods of the day (such as peak
27
traffic periods) or by prohibiting particular turning movements altogether. Turn
restrictions and prohibitions can be implemented by signing.
Target- Unsignalized intersections with patterns of crashes related left turning
movements when it is impractical to construct a passing flare or left turn lane.
2.10
Close or Relocate “High-Risk” Intersections
For some unsignalized intersections with high crash histories, the best method of
improving safety may be to close or relocate the intersection. This is a radical
approach to safety improvement that should generally be considered only when
less restrictive measures have been tried and have failed. Intersection relocation
can be accomplished by realigning the minor-road approaches so that they
intersect the major road at a different location or a different angle. Intersection
closure can be accomplished by closing and abandoning the intersecting minor
streets or by converting those minor streets so that they dead-end before reaching
their former intersection with the major street.
Target- Intersections with high numbers of intersection related crashes that other
countermeasures have been unsuccessful in correcting.
2.11
Convert One Four-Leg Intersection to Two T-Intersections
For some unsignalized four-legged intersections with very low through volumes
on the cross street, the best method of improving safety may be to convert the
intersection to two T-intersections. This conversion to two T-intersections can be
accomplished by separating the two cross-street approaches an appreciable
distance along the major road, thus creating two separate T-intersections that
operate independently of one another. The intersections should be separated
enough to ensure the provision of adequate turn-lane channelization on the major
road to prevent left turns interlocking. See GEO-640 Series.
Target- Unsignalized four-legged intersections with very low through volumes on
the cross street, that have skewed geometry.
2.12
Convert Offset T-Intersections to One Four-Leg Intersection
For some unsignalized offset T-intersections with very high through volumes on
the cross street, the best method of improving safety may be to convert the
intersection to a single four-legged intersection. This conversion to a four-legged
intersection can be accomplished by realigning the two cross-street approaches to
meet at a single point along the major road, thus creating one four-legged
intersection. See GEO-604 Series.
Target- Unsignalized offset T- intersections with very high through volumes on
the cross street.
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2.13
Realign Intersection Approaches to Reduce or Eliminate
Intersection Skew
When roadways intersect at skewed angles, the intersections may experience one
or more of the following problems:
• Vehicles may have a longer distance to traverse while crossing or turning
onto the intersecting roadway, resulting in an increased time of exposure
to the cross-street traffic.
• Older drivers may find it more difficult to turn their head, neck, or upper
body for an adequate line of sight down an acute-angle approach.
• The driver’s sight angle for convenient observation of opposing traffic and
pedestrian crossings is decreased.
• Drivers may have more difficulty aligning their vehicles as they enter the
cross street to make a right or left turn.
• Drivers making right turns around an acute-angle radius may encroach on
lanes intended for oncoming traffic from the right.
• The larger intersection area may confuse drivers or cause them to deviate
from the intended path.
• Through-roadway drivers making left turns across an obtuse angle may
attempt to maintain a higher than normal turning speed and cut across the
oncoming traffic lane on the intersecting street.
• The vehicle body may obstruct the line of sight of drivers with an acuteangle approach to their right.
Realignment of intersection approaches to reduce or eliminate intersection skew
may be desirable to improve safety at a skewed intersection. See Geometric
Design Guide GEO-640 Series.
Target- Reduce the frequency of crashes resulting from insufficient intersection
sight distance and awkward sight lines at a skewed intersection.
2.14
Use Indirect Left-Turn Treatments to Minimize Conflicts at
Divided Highway Intersections
Many intersection operational and safety problems at two-lane and dividedhighway intersections can be traced to difficulties of accommodating left-turn
demand. Such difficulties involve both demand volume and the frequency of
demand along a corridor. Furthermore, vehicles that slow down or stop to turn left
in a lane used primarily by through traffic increase the potential for rear-end
collisions. One way to address the impacts of such left-turn movements is the use
of indirect left-turn treatments. Indirect left-turn treatments include the use of jughandle roadways before the crossroad, loop roadways beyond the crossroad, and
directional median crossovers beyond the crossroad, see Geometric Design Guide
VII-670. Indirect left turn treatments enable drivers to make left turns efficiently
on divided highways, including highways with relatively narrow medians.
29
Target- Unsignalized intersections with operational and safety problems that can
be traced to difficulties of accommodating left-turn demand.
3.0
Improve Pedestrian and Bicycle Facilities to Reduce Conflicts Between
Motorists and Non-Motorists
Nearly one-third (32.2 percent) of all pedestrian-related crashes occur at or within 50 feet
of an intersection. Of these, 30 percent involve a turning vehicle. Another 22 percent of
pedestrian crashes involve a pedestrian either running across the intersection or darting
out in front of a vehicle whose view was blocked just prior to the impact. Finally, 16
percent of these intersection-related crashes occur because of a driver violation (e.g.,
failure to yield right-of-way). Improvements to pedestrian facilities (short of grade
separation) that may reduce conflicts between motorists and nonmotorists include
• Continuous sidewalks;
• Signed and marked crosswalks;
• Pedestrian signs, signals, and markings;
• Sidewalk set-backs; and
• Lighting.
Some of the problems that bicyclists face at intersections include high traffic volumes
and speeds and lack of space for bicyclists. Possible improvement projects include:
• Widening the outside through lanes or adding bike lanes,
• Providing median refuges at key minor-street crossings,
• Providing independent bicycle/pedestrian structures where necessary,
• Replacing drain grates with bicycle-safe models, and
• Providing smooth paved shoulders.
Further details may be found in the implementation guide for addressing pedestrian
crashes. FHWA maintains a site that provides detailed information on pedestrian crash
countermeasures at intersections
4.0
Improve Sight Distance
4.1
Improve Intersection Sight Distance at Unsignalized Intersections
Adequate sight distance for drivers at stop or yield controlled approaches to
intersections has long been recognized as among the most important factors
contributing to overall safety at unsignalized intersections. Estimates of the safety
effectiveness of providing adequate intersection sight distance (ISD) where it does
not currently exist suggest that up to a 20-percent reduction in related crashes can
be expected. Sight distance improvements can often be achieved at relatively
low cost by clearing sight triangles to restore sight distance obstructed by
vegetation, roadside appurtenances, or other natural or artificial objects. See
AASHTO Policy on Geometric Design of Highways and Streets and MDOT Sight
Distance Guidelines.
30
Target- Unsignalized intersections that have restricted sight distance where
improvements can be made by removing obstructions to reduce patterns of
crashes related to a lack of adequate intersection sight distance.
4.2
Clear Sight Triangles in the Medians of Divided Highways
Near Intersections
Adequate sight distance for drivers at stopped approaches to intersections has
long been recognized as among the most important factors contributing to overall
safety at unsignalized intersections. A particular concern at divided highway
intersections is sight obstructions located in the highway median. Such
obstructions can restrict sight distance for drivers of vehicles passing through the
median, including through vehicles on the crossroad and vehicles making left
turns onto and off of the divided highway. Sight obstructions can include
vegetation, roadside appurtenances, or other natural and artificial objects. Since
sight obstructions located in the highway median are located in the highway rightof-way, MDOT has the authority to remove them.
Target- Unsignalized intersections on divided highways that have restricted sight
distance where improvements can be made by removing obstructions in the
median, and where there is a pattern of crashes related to the lack of sight
distance.
4.3
Change Horizontal and/or Vertical Alignment of Approaches to
Provide More Sight Distance
This strategy addresses costly geometric improvements that involve changing the
horizontal or vertical alignment of the intersecting roadways. Such strategies
should generally be considered only at intersections with a persistent crash pattern
that cannot be ameliorated by less expensive methods.
Target- Unsignalized intersections with restricted sight distance due to horizontal
and vertical alignment, and with pattern of crashes related to the lack of sight
distance where less expensive countermeasures have not reduced crashes.
4.4
Eliminate Parking that Restricts Sight Distance
Although geometrically an intersection might have adequate sight distance,
parking within the sight triangle might restrict it and should, therefore, be taken
into consideration. Estimates of the safety effectiveness of eliminating parking
that restricts sight distance have not been yet developed.
Target- Unsignalized intersections where parked cars restrict intersection sight
distance and have a pattern of right angle or turning crashes.
31
5.0
Improve Driver Awareness of Intersections as Viewed From the Intersection
Approach
5.1
Improve Visibility of Intersections by Providing Enhanced Signing
and Delineation
Many unsignalized intersections are not readily visible to approaching drivers,
particularly drivers on major-road approaches that are not controlled by stop or
yield signs. Thus, intersection crashes may occur because approaching drivers
may be unaware of the presence of the intersection. The visibility of intersections
and, thus, the ability of approaching drivers to perceive them can be enhanced by
signing and delineation. Improvements may include advance guide signs,
advance street name signs, warning signs, pavement markings, and post-mounted
delineators.
The FHWA Older Driver Highway Design Handbook (Staplin et al., 1998)
encourages such improvements to contribute to a better driving environment for
older drivers. In particular, the handbook addresses advance guide signs and letter
height on guide signs as key issues for older drivers. Advance warning signs, such
as the standard intersection warning sign, can also alert drivers to the presence of
an intersection. Providing a break in pavement markings—including centerlines,
lane lines, and edge lines—at intersections also helps to alert drivers to the
presence of an intersection.
Target- Intersections that are not clearly visible to approaching traffic, and have
a pattern of rear-end, right-angle, or turning crashes related to driver not being
unaware of the intersection.
5.2
Improve Visibility of the Intersection by Providing Lighting
Providing lighting at the intersection itself, or both at the intersection and on its
approaches, can make drivers aware of the presence of the intersection and reduce
nighttime crashes. Lighting is the responsibility of the local government agency.
Target- Unsignalized intersections with a substantial pattern of night time
crashes, such as rear-end, right angle, or turning collisions.
5.3
Install Larger Regulatory and Warning Signs at Intersections
The visibility of intersections and, thus, the ability of approaching drivers to
perceive them can be enhanced by installing larger regulatory and warning signs
at intersections. Such improvements may include advance guide signs, doubling
up warning signs, pavement markings, post-mounted delineators, and adding
reflective strips to the sign posts. The FHWA Older Driver Highway Design
Handbook encourages such improvements to contribute to a better driving
environment for older drivers.
32
Target- Unsignalized intersections with a substantial pattern of rear-end, right
angle, or turning collisions related to drivers not being aware of an intersection.
5.4
Install Rumble Strips On Intersection Approaches
Rumble strips can be installed on intersection approaches to call attention to the
presence of the intersection and to the traffic control in use at the intersection.
Rumble strips are particularly appropriate on stop-controlled approaches to
intersections where a pattern of crashes is present related to lack of driver
recognition of the presence of the stop sign.
Rumble strips should be used sparingly. Their effectiveness is dependent on being
unusual. Rumble strips are normally applied when less intrusive measures—such
as pavement markings, “STOP AHEAD” signs, or flashers—have been tried and
have failed to correct the crash pattern. Rumble strips can be used to supplement
such traffic control devices. For example, a rumble strip can be located so that
when the driver crosses the rumble strip, a key traffic control device such as a
“STOP AHEAD” sign is directly in view. Rumble strips in the traveled way can
also be used on a temporary basis to call attention to changes in traffic control
devices, such as installation of a stop sign where none was present before. See
Traffic and Safety Note 609 (7.11).
Target- Locations should be identified by patterns of crashes related to lack of
driver recognition of traffic control devices at an intersection (e.g. right-angle
crashes related to stop sign violations).
5.5
Provide Supplementary Stop Signs Mounted Over the
Roadway
Many stop signs at stop-controlled intersections are not readily visible to
approaching drivers due to geometric conditions, presence of vegetation, or other
objects (such as tall vehicles) that can limit the view of the regular stop signs.
Thus, intersection crashes may occur because approaching drivers may be
unaware of the presence of the stop sign at the intersection. The visibility of stop
signs and, thus, the ability of approaching drivers to perceive them can be
enhanced by providing supplementary stop signs suspended over the roadway.
Target- Unsignalized intersections with stop signs that are not clearly visible to
approaching motorists. The strategy is particularly appropriate for intersections
with patterns of rear-end, right-angle, or turning collisions related to lack of
driver awareness of the presence of the intersection or stop sign.
33
5.6
Provide Pavement Markings with Supplementary Messages,
Such as STOP AHEAD
Providing pavement markings with supplementary messages (such as STOP
AHEAD) can help alert drivers and thus enhance the ability of approaching
drivers to be more aware of the presence of the intersection. These marking
should follow MMUTCD guidelines.
Target- This strategy is particularly appropriate for intersections with patterns of
rear-end, right-angle, or turning collisions related to lack of driver awareness of
the presence of the intersection or stop sign.
5.7
Install Intersection Control Beacons at Stop-Controlled Intersections
Overhead flashing beacons can be used at stop-controlled intersections to
supplement and call driver attention to stop signs. Flashing beacons are intended
to reinforce driver awareness of the stop sign and to help mitigate patterns of
right-angle crashes related to stop sign violations. At two-way stop-controlled
intersections, flashing beacons are used with red flashers facing the stopcontrolled approaches and yellow flashers facing the unstopped approaches. At
all-way stop-controlled intersections, red flashers face all approaches. Use of
overhead flashing beacons can increase the visibility of intersections for
approaching drivers, thus supplementing the signing and delineation
improvements discussed previously. Intersection control beacons can also be used
on intersection approaches to supplement and call attention to stop signs or STOP
AHEAD signs. See the MMUTCD for guidance.
Target- This strategy is particularly appropriate for unsignalized intersections
with patterns of right-angle crashes related to lack of driver awareness of the
presence of the intersection or stop control.
6.0
Choose Appropriate Intersection Traffic Control to Minimize Crash
Frequency and Severity
6.1
Avoid Signalizing Through Roads
Signalization of an intersection often leads to an increased frequency of crashes
on major roadways. Signals associated with new developments introduce
congestion and increase crashes on through roadways that previously operated
relatively safely and smoothly. Thus, the key to crash reduction is to avoid
installing signal control whenever possible. Alternatives to signal control include
all-way stop control; roundabouts; turn prohibitions (e.g., limiting movements to
right-turn in and right-turn out); indirect left-turn movements (e.g., jug handles,
loops, and median crossovers); and provision of flyovers and other grade
separations.
34
Target- Medium to high volume intersections where signalization is being
considered.
6.2
Provide All-Way Stop Control at Appropriate Intersections
All-way stop control can reduce right-angle and turning collisions at unsignalized
intersections by providing more orderly movement at an intersection, reducing
through and turning speeds, and minimizing the safety effect of any sight distance
restrictions that may be present. However, all-way stop control is suitable only at
intersections with moderate and relatively balanced volume levels on the
intersection approaches. Under other conditions, the use of all-way stop control
may create unnecessary delays and aggressive driver behavior. See MMUTCD
for warrants
Target- Unsignalized intersections with patterns of right-angle and turning
collisions and moderate and relatively balanced traffic volumes on the
intersection.
6.3
Provide Roundabouts at Appropriate Locations
Roundabouts provide an important alternative to signalized and all-way stopcontrolled intersections. Modern roundabouts differ from traditional traffic circles
in that they operate in such a manner that traffic entering the roundabout must
yield the right-of-way to traffic already in it. Roundabouts can serve moderate
traffic volumes with less delay than signalized or all-way stop-controlled
intersections because traffic can normally traverse the roundabout without
stopping.
Target-See roundabout section.
7.0
Guide Motorists More Effectively Through Complex Intersections
7.1
Provide Turn Path Markings
At most intersections, pavement markings are provided on the intersection
approaches, but the pavement markings end near the stop line. Rarely are
pavement markings extended into or continued through intersections. At complex
intersections, however, it may be beneficial to provide motorists with additional
information to help with vehicle positioning through the intersections. In
particular, it may be desirable to extend pavement markings through intersections
that have offset approaches, are skewed, have multiple turn lanes, or are located at
unsignalized ramp terminals. This approach is especially useful for delineating
vehicle turning paths through an intersection. The MMUTCD and MDOT
Pavement Marking Special Details/Standard Plans provide guidance on extending
pavement markings through intersections.
35
Target- Intersections where stop sign violations and patterns of crashes related to
stop sign violations have been observed. Crash types include right-angle and
turning collisions.
7.2
Provide Lane Assignment Signing or Marking at Complex
Intersections
Sometimes, as drivers approach a complex intersection, they have difficulty
determining the appropriate lane from which to perform a certain maneuver. This
can cause indecision among drivers and result in maneuvers being made from
certain lanes that are unexpected. These maneuvers could potentially lead to
crashes. Crash patterns that are characteristic of driver indecision related to lane
assignment include rear-end and sideswipe crashes on intersection approaches and
potentially angle crashes when a driver performs an unexpected maneuver from
an inappropriate lane (e.g., a vehicle makes a left turn from a through lane).
Providing lane assignment signs (or markings) to guide motorists through
complex intersections can alleviate this confusion and lead to safer driving
conditions. Pavement markings are often used to supplement lane assignment
signs.
Target- This strategy is to reduce crashes caused by driver indecision in lane
assignment.
36
APPENDIX B
TABLE OF CONTENTS
MDOT Roundabout Quick Guide
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
Introduction..................................................................................................1
Basic Terminology And Information...........................................................1
Planning .......................................................................................................2
3.1
Typical Locations and Applications ................................................2
3.2
Locations Needing Careful Review .................................................3
3.3
Data for Operational Review/Feasibility .........................................3
Safety ..........................................................................................................3
Design Information ......................................................................................4
Operational Analysis....................................................................................4
MDOT Intersection Comparison Matrix Tool.............................................6
Miscellaneous Topics...................................................................................6
1.0
Introduction
This quick guide is a very brief summary that describes some basic roundabout terminology, identifies
some of the situations where roundabouts could be used, outlines procedures for determining the
feasibility of a roundabout, and summarizes how to perform operational analyses for roundabouts.
Additional information and details regarding MDOT’s policy can be found in MDOT’s Roundabout
Guidance Document.
2.0
Basic Terminology And Information
The following terms are some of the most commonly used relative to roundabouts.
A single-lane roundabout is a roundabout with one entering lane per approach.
Two-lane roundabouts have at least one entry with two lanes separated by pavement markings and are
more complex.
Three-lane roundabouts have at least one entry with three lanes.
A bypass lane or right turn bypass lane is typically used to accommodate heavy right turn movements
to improve the capacity of a roundabout. The bypass lane is typically separated from an entrance by a
curbed island and allows right-turning traffic to avoid entering the roundabout. The decision to use bypass
lanes should take into account pedestrian and ROW constraints. In some cases, bypass lanes provide
significant benefits, especially for rural interchanges.
Entry Width is the width of an approach where it enters the roundabout.
Flare Length is the distance over which the approach roadway widens to the entry width. Longer flare
lengths give motorists more time to adjust and utilize all lanes.
The Entry Radius is the radius of the outside curb at the entry.
Inscribed Circle Diameter is also abbreviated as ICD. This is the outside diameter of the roundabout.
The figure below also shows these common terms as they relate to an actual roundabout.
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November 2007
1
Some other common elements are:
•
•
•
Signing and pavement markings – provides notification and guidance to drivers
Lighting – helps drivers identify intersection features such as splitter islands and curbs at decision
points
Landscaping – can help to direct drivers’ attention where you want them to look and enhance
aesthetics.
Table 1 describes typical roundabout types and sizes based on traffic volumes.
Table 1. Typical Roundabout Capacities and Inscribed Circle Diameters
Approximate Peak Hour Capacity
Inscribed Circle Diameter
Type of Roundabout
(Combined entering volume for all approaches)
Compact Urban
Up to 4,000 vehicles per hour
90’ – 130’
Single Lane
Up to 2,000 vehicles per hour
120’ – 170’
Two Lane
Up to 4,000 vehicles per hour
145’ – 200’
Three Lane
Up to 7,000 vehicles per hour
210’ – 250’
3.0
Planning
3.1
Typical Locations and Applications
Implementation of roundabouts can be beneficial to the traveling public in a wide variety of situations.
The list which follows below identifies some of the most common locations and/or applications where
installation of a roundabout may be advantageous.
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2
•
•
•
•
•
•
•
•
•
High-speed rural intersections (approach design speed >45 mph)
Intersections with high injury crash histories (80% reduction factor based on research)
Intersections with traffic operational problems
Closely spaced intersections
Intersections near structures (fewer approach lanes for roundabouts can reduce costs)
Freeway interchanges (vehicles exit roundabouts randomly spaced and need fewer lanes)
As part of an access management program (accommodate U-turns with closed medians)
Intersections with unusual geometry (roundabout geometry is relatively flexible)
Multi-leg intersections (i.e. five or more legs)
3.2
Locations Needing Careful Review
As might be expected, there are also locations and applications where roundabouts may not be beneficial,
and as with traffic signals, care should be exercised when considering a roundabout in these situations.
•
•
•
•
•
Intersections within a system of coordinated signals (multiple signals with good progression).
Intersections with steep grade running through the intersection (greater than 5%)
Intersections where stopping sight distance cannot be achieved
Intersections near railroad crossings (careful evaluation of queue lengths)
Closely spaced intersections (careful evaluation of queue lengths)
3.3
Data for Operational Review/Feasibility
During the scoping phase of a project, data is required to adequately analyze the operations of a
roundabout and its feasibility. Data that is typically needed in order to evaluate a roundabout would
include the following:
•
•
•
•
•
•
•
•
•
•
Existing AM and PM peak hour turning movement counts
MDOT approved design year (i.e., 20-year) AM and PM peak hour turning movement projections
Design vehicle to be accommodated
Base mapping (either aerial photograph, aerial mapping, or survey)
Right-of-way mapping
Crash data for the most recent three-year period available
Location of nearby intersections and signal timing information (if applicable)
Location of any major constraints near the intersection (i.e. expensive ROW, major utilities,
structures, railroad crossings, water bodies)
Existing and future planned bicycle and pedestrian facilities
Truck percentages
Data that is desirable to obtain, though not necessarily required in all situations, includes:
•
•
•
4.0
Existing pedestrian counts
Previously prepared construction plans or as-built plans showing the existing intersection(s)
Utility information
Safety
U.S. studies have shown that relative to other intersection types, roundabouts typically reduce overall
crashes by approximately 40 percent, reduce injury crashes by approximately 75 percent, and reduce
serious injury and fatal crashes by about 90 percent (Insurance Institute for Highway Safety, 2000). Thus,
MDOT Roundabout Quick Guide
November 2007
3
the potential for improved intersection safety in Michigan is substantial. The figure below shows the
differences in the number and type of conflict points between a standard intersection and a roundabout.
In addition to reducing the number of conflict points, a roundabout also eliminates the types of conflicts
that typically result in the most serious crashes (i.e., left turn head-on crashes and angle crashes).
5.0
Design Information
When developing roundabout geometry, following the guidance provided in this document and Section 4
of MDOT’s Roundabout Guidance Document is extremely important in order to ensure the safest possible
geometric design. Section 4 of the supplement document provides information regarding geometric
design (including information on sight distance, geometric layout, grades, cross slopes, etc.). Table 1
provides some general ranges of roundabout sizes.
6.0
Operational Analysis
This section is a summary that outlines procedures for conducting a roundabout operational analysis.
Sections 2 and 4 of MDOT’s Roundabout Guidance Document provide additional information
regarding operational analysis for roundabouts.
General Process
The operational analysis should begin by using Rodel software to determine the required geometry and
corresponding queues and delays for 20-year peak hour turning movement volumes. Rodel software
should be used to analyze roundabout capacity and determine roundabout geometry in all cases. When
conducting this analysis, geometric parameters should be adjusted through an iterative process to achieve
the desired delays and Level of Service (LOS) in each peak hour. During this optimizing process, the
designer needs to keep in mind site constraints and other roundabout design principles related to speed
control so that the geometric parameters entered into Rodel are realistic. Once preferred geometry has
been identified, lane balance and utilization should be tested on multilane roundabout models for both
peak hours by manipulating the “capacity factor” function in Rodel.
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November 2007
4
Confidence Level Analysis
Capacity analyses should initially be conducted at the 50 percent confidence level setting in Rodel. Once
acceptable geometry has been identified, it should be tested at the 85 percent confidence level, and
geometry should be adjusted if necessary (the 85 percent confidence level assumes below average
capacity and builds in a reasonable safety buffer). When adjusting the geometry, each entrance should
function at level of service D or better (level of service B or better is preferred when possible) at the 85
percent confidence level. Note that the 50 percent confidence level results should be used in reporting
queues, delays, and level of service and for comparison to other intersection alternatives being
considered.
Flow Ratio
Rodel does not use a peak hour factor when calculating queues and delays. Instead it uses the “flow
ratio” parameter to represent the rise and fall of traffic during a peak hour. In most cases, the default flow
ratio should be used. However, certain unique situations with very high or very low peak hour factors
may warrant adjustment of the flow ratio to more accurately represent the peak within the peak hour.
Accounting for Trucks and Pedestrians
Designers need to exercise care when evaluating single lane roundabouts using Rodel when entries are
going to be wide (i.e., 18 to 20 feet) to accommodate trucks. Rodel assumes these widths represent two
narrow entry lanes instead of one wide lane. When only one entering and one circulating lane are actually
present at these widths, this results in over prediction of capacity and under prediction of delays and
queues. Therefore, single lane entries should be modeled in Rodel at 15 feet or less with 13 to 14 feet
being more conservative yet. This capacity analysis procedure will be reasonably conservative and should
be used even when actual entry geometry is designed wider to accommodate trucks.
High volumes of pedestrians and trucks can reduce the capacity of roundabouts. Truck percentages should
be represented by modifying Rodel inputs. In situations with relatively high pedestrian volumes, the effect
on capacity can be assessed by using the pedestrian capacity reduction factors noted in Exhibits 4-7 and
4-8 of the FHWA roundabout guide. These factors can be entered into the capacity factor field of Rodel
for each leg of the roundabout.
Right Turn Bypass Lanes
Bypass lanes are used mainly in situations were a large portion of turning movements are right turns.
Typically, bypass lanes should only be used when other geometric layouts fail to provide acceptable
traffic operations, and the decision to use bypass lanes should take into account pedestrian
volumes/facilities and ROW constraints. Two types of bypass lanes may be used. The first is a free flow
bypass lane which allows vehicles to bypass the roundabout and then merge into the exiting stream of
traffic. The second type is a semi-bypass lane which requires approaching vehicles to yield to traffic
leaving the adjacent exit.
Geometric Delay
Most software that is used to evaluate intersections controlled by traffic signals reports delays in the form
of “control” delay. Control delay includes both stop delay (the time when a vehicle is actually stopped
while waiting to enter an intersection) and “geometric” delay (the time that is lost as a vehicle decelerates
while approaching an intersection, maneuvers through the intersection, and accelerates away before
reaching its original speed). Rodel reports delays in the form of “stop” delay. Geometric delay for
roundabouts can be estimated to allow comparison against control delay reported for intersections
controlled by signals. The MDOT Roundabout Guidance Document provides more details regarding this
process.
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Reporting Results
Results of the operational analysis can be reported and compared against other potential intersection
improvement options. Typically, reported results (at the 50% confidence level) would include delay,
level of service, and the estimated design life in years.
7.0
MDOT Intersection Comparison Matrix Tool
MDOT’s evaluation matrix template was developed in order to aid in the decision making process Table
2). The matrix can be used as a tool to help a designer or manager weigh the advantages of different
types of intersections. The more complete the information used in the matrix, the better the choice which
can be made. This matrix can be used for safety, scoping, and Early Preliminary Engineering (EPE)
studies.
8.0
Miscellaneous Topics
More detailed information for the following topics may be found in MDOT’s Roundabout
Guidance Document:
•
•
•
•
•
•
•
•
Signing
Pavement Markings
Maintenance of Traffic
Accommodation of Design Vehicle
Three-lane Roundabouts
Lighting
Landscaping
Public Involvement
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6
Table 2. MDOT Intersection Comparison Matrix Tool (For Safety, Scoping, and EPE Studies)*
Road Improvement
Alternatives/Options
Total Cost
Estimate*
Control Delay**
Level of
Service
Design Life
Cost/Benefit
Ratio***
Safety Benefits
ROW Impacts
(acres)
Environmental
Issues
Potential Utility
Conflicts
Construction
Impacts
Driveway
Accommodation/
Good Access
Management
Public Input/
Community
Support
* Additional information regarding this matrix can be found on the next page.
** Roundabout delays from Rodel are stop delay, while delay for other intersections in HCS/Synchro are control delay. In order to evenly compare these numbers, geometric delay should be added to roundabout stop delay from Rodel to get
control delay. See MDOT’s Roundabout Guidance Document for more information on calculating roundabout geometric delay.
***For more information regarding C/B methodology, see the last page of this document.
The following criteria may also be helpful for comparing alternatives:
•
•
•
•
•
•
•
•
•
•
•
Is funding available?
Are traffic counts/projections available (Existing, 10-year, or 20-year)?
Does the alternative create the potential for enhancements?
Are bike/pedestrian facilities present or planned?
Are bike accommodations required?
What is the percentage of heavy truck traffic?
Is the intersection designed for trucks?
Is the intersection located within a system of progressed traffic signals?
Is the intersection adjacent to bridge or railroad crossing?
Is the intersection adjacent to another intersection?
Pedestrian Count___________
****Note: If pedestrian counts meet or exceed traffic signal warrants for pedestrians as detailed in the current MMUTCD and a Roundabout is the preferred intersection, than this intersection must be approved by MDOT’s Engineering
Operations Committee (EOC).
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MDOT INTERSECTION COMPARISON MATRIX
Below is a brief description of all of Matrix items.
•
•
•
•
•
•
•
•
•
•
•
•
•
Road Improvement Alternatives/Options – Alternatives are the potential solutions being
considered for each location. Options are variations within an alternative. (e.g., for Alternative 1
- Upgraded Signalized Intersection, there could be two options which are Alternative 1a Upgraded Signalized Intersection with dual left turn lanes and Alternative 1b - Upgraded
Signalized Intersection with single left turn lanes and different signal timing.)
Cost Estimate – Total cost. Can consist of safety, CMAC, R&R, EDA, capacity, local, etc.
Delay – Average seconds of control delay per vehicle
LOS – Level of Service
Design Life – Typical 10 or 20 years
Cost Benefit Ratio (C/B) – Includes maintenance and safety and delay costs (see the following
page for calculations)
Safety Benefits – Text description of potential safety improvements
ROW Impacts – Text description and acreage of impacts
Environmental Issues – Text description of any potential environmental impacts (e.g. wetlands,
cultural resources, etc.)
Potential Utility Conflicts – Text description of potential utility conflicts (e.g. water/sewer lines,
utility poles, etc.)
Construction Impacts – Text description of construction on local roads, business, traffic etc.
Driveway/Access Management – Text description of how easy the project will fit relative to other
options
Public Input/Community Support – Input on each option
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C/B
=
T+[(M+E) X L]
[(D+A) x L]
Calculation of Cost/Benefit Ratio
T
=
Total Cost: All costs related to the proposed alternative including PE, CE and
Right-of-Way costs.
M
=
Maintenance Cost: All anticipated yearly maintenance cost in dollars per year.
Typical yearly maintenance cost for a signalized intersection is $1200, and a
roundabout is $0.00.
E
=
Energy Cost: The total expected yearly energy cost in dollars per year. Typical
energy cost for signalized intersection is $550, and a roundabout is $1800.
L
=
Design Life: The projected design life for all options. Typically this value is 20
years.
A
=
Accident Reduction Factor: The annual benefit from the reduction of crashes.
This value is provided by MDOT Traffic and Safety staff.
D
=
Average Delay Cost: The total benefit from the reduction in delay between the
existing condition and proposed alternative. It is calculated as follows:
D
=
[Delay (Existing*) – Delay (Proposed*)] x ADT x N x Z
3600
Delay =
AM peak delay**(sec/veh) + PM peak delay** (sec/veh)
2
*
The above delay should be computed for the existing conditions with future projected
traffic volumes and for the proposed conditions with the projected 20 year traffic
volumes for each alternative.
**
Add geometric delay for roundabouts according to the MDOT Roundabout Guide to the
average delay provided by RODEL.
ADT =
Average daily traffic. If not known, compute as follows:
ADT =
(AM + PM peak volumes) x 10
2
N
=
Number of days per year (365 days)
Z
=
Hourly delay Cost/Vehicle ($14.83). This dollar value should be updated yearly.
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APPENDIX C
Intersection Crash Reports (2004-2006)
Intersection crash reports can be used to determine if an existing intersection has more
than the average number of crashes when compared to similar locations. When
reviewing crashes, special attention should be given to the severity of the crashes even if
the total number of crashes is lower than the average for similar intersections.
The following data includes the average number of crashes per year that occurred
during the three year period 2004-2006 for:
•
•
•
•
Various types of intersections (i.e. 2 Lane 2 Way, Divided Road, etc…).
Different traffic control (Unsignalized, Signalized).
Various ADT levels (ADT Less Than 10,000, ADT 10,000 to 20,000, and Greater
Than 20,000).
Different geographic locations (North and Superior Regions, the remaining
Regions).
Notes regarding the following data:
•
•
•
•
The data is the average number of crashes per year that occurred during the three
year period 2004-2006.
Animal crashes were excluded.
Analysis includes intersection related crashes only.
Intersection crashes include:
1. All crashes on the trunkline that occurred 150’ from the intersection.
2. Crashes that occurred on the trunkline half way between adjacent
intersections and coded as an intersection crash.
3. Crossroad crashes that occurred 150’ from the intersection.
NORTH & SUPERIOR REGIONS
2 Lane 2 Way
Unsignalized Intersections ADT Less Than 10,000 ................................................1
Signalized Intersections ADT Less Than 10,000 ....................................................2
Unsignalized Intersections ADT 10,000 to 20,000..................................................3
Signalized Intersections ADT 10,000 to 20,000......................................................4
Unsignalized Intersections ADT Greater Than 20,000............................................5
Signalized Intersections ADT Greater Than 20,000................................................6
3 Lane 2 Way
Unsignalized Intersections ADT Less Than 10,000 ................................................7
Signalized Intersections ADT Less Than 10,000 ...................................................8
Unsignalized Intersections ADT 10,000 to 20,000 .................................................9
Signalized Intersections ADT 10,000 to 20,000 ...................................................10
Unsignalized Intersections ADT Greater Than 20,000 .........................................11
Signalized Intersections ADT Greater Than 20,000 .............................................12
4 Lane 2 Way
Unsignalized Intersections ADT Less Than 10,000 .............................................13
Signalized Intersections ADT Less Than 10,000 .................................................14
Unsignalized Intersections ADT 10,000 to 20,000 ...............................................15
Signalized Intersections ADT 10,000 to 20,000 ...................................................16
Unsignalized Intersections ADT Greater Than 20,000 .........................................17
Signalized Intersections ADT Greater Than 20,000 .............................................18
5 Lane 2 Way
Unsignalized Intersections ADT Less Than 10,000 .............................................19
Signalized Intersections ADT Less Than 10,000 .................................................20
Unsignalized Intersections ADT 10,000 to 20,000 ..............................................21
Signalized Intersections ADT 10,000 to 20,000 ...................................................22
Unsignalized Intersections ADT Greater Than 20,000..........................................23
Signalized Intersections ADT Greater Than 20,000 .............................................24
7 Lane 2 Way
Unsignalized Intersections ADT Less Than 10,000 .............................................25
Signalized Intersections ADT Less Than 10,000 .................................................26
Unsignalized Intersections ADT 10,000 to 20,000................................................27
Signalized Intersections ADT 10,000 to 20,000 ...................................................28
Unsignalized Intersections ADT Greater Than 20,000 .........................................29
Signalized Intersections ADT Greater Than 20,000 .............................................30
Divided Road
Unsignalized Intersections ADT Less Than 10,000 .............................................31
Signalized Intersections ADT Less Than 10,000 .................................................32
Unsignalized Intersections ADT 10,000 to 20,000 ...............................................33
Signalized Intersections ADT 10,000 to 20,000 ...................................................34
Unsignalized Intersections ADT Greater Than 20,000 .........................................35
Signalized Intersections ADT Greater Than 20,000..............................................36
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
2 Lane 2 Way
Unsignalized Intersections ADT Less Than 10,000 .............................................37
Signalized Intersections ADT Less Than 10,000 .................................................38
Unsignalized Intersections ADT 10,000 to 20,000 ...............................................39
Signalized Intersections ADT 10,000 to 20,000 ...................................................40
Unsignalized Intersections ADT Greater Than 20,000 .........................................41
Signalized Intersections ADT Greater Than 20,000 .............................................42
3 Lane 2 Way
Unsignalized Intersections ADT Less Than 10,000 .............................................43
Signalized Intersections ADT Less Than 10,000 .................................................44
Unsignalized Intersections ADT 10,000 to 20,000 ...............................................45
Signalized Intersections ADT 10,000 to 20,000 ...................................................46
Unsignalized Intersections ADT Greater Than 20,000 .........................................47
Signalized Intersections ADT Greater Than 20,000 .............................................48
4 Lane 2 Way
Unsignalized Intersections ADT Less Than 10,000 .............................................49
Signalized Intersections ADT Less Than 10,000 .................................................50
Unsignalized Intersections ADT 10,000 to 20,000 ...............................................51
Signalized Intersections ADT 10,000 to 20,000 ...................................................52
Unsignalized Intersections ADT Greater Than 20,000 .........................................53
Signalized Intersections ADT Greater Than 20,000..............................................54
5 Lane 2 Way
Unsignalized Intersections ADT Less Than 10,000 .............................................55
Signalized Intersections ADT Less Than 10,000 .................................................56
Unsignalized Intersections ADT 10,000 to 20,000 ...............................................57
Signalized Intersections ADT 10,000 to 20,000 ...................................................58
Unsignalized Intersections ADT Greater Than 20,000 .........................................59
Signalized Intersections ADT Greater Than 20,000 .............................................60
7 Lane 2 Way
Unsignalized Intersections ADT Less Than 10,000 .............................................61
Signalized Intersections ADT Less Than 10,000 .................................................62
Unsignalized Intersections ADT 10,000 to 20,000 ...............................................63
Signalized Intersections ADT 10,000 to 20,000 ...................................................64
Unsignalized Intersections ADT Greater Than 20,000 .........................................65
Signalized Intersections ADT Greater Than 20,000 .............................................66
Divided Road
Unsignalized Intersections ADT Less Than 10,000 .............................................67
Signalized Intersections ADT Less Than 10,000 .................................................68
Unsignalized Intersections ADT 10,000 to 20,000 ...............................................69
Signalized Intersections ADT 10,000 to 20,000 ...................................................70
Unsignalized Intersections ADT Greater Than 20,000 .........................................71
Signalized Intersections ADT Greater Than 20,000 .............................................72
2004-2006 2 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
3,482
TOT INTERSECTIONS = 5,404
AVERAGE
ANNUAL FREQ
1609
443
12
232
165
407
59
72
1
4
91
44
7
8
307
25
0
9
31
240
267
78
92
59
22
17
32
30
57
48
3
6
AVG ANNUAL
CRASHES/INT
% OF TOTAL
0.30
0.08
0.00
0.04
0.03
0.08
0.01
0.01
0.00
0.00
0.02
0.01
0.00
0.00
0.06
0.00
0.00
0.00
0.01
0.04
0.05
0.01
0.02
0.01
0.00
0.00
0.01
0.01
0.01
0.01
0.00
0.00
100.0%
27.5%
0.7%
14.4%
10.3%
25.3%
3.7%
4.5%
0.1%
0.2%
5.7%
2.7%
0.4%
0.5%
19.1%
1.6%
0.0%
0.6%
1.9%
14.9%
16.6%
4.8%
5.7%
3.7%
1.4%
1.1%
2.0%
1.9%
3.5%
3.0%
0.2%
0.4%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
1
2004-2006 2 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
5,188
TOT INTERSECTIONS = 58
AVERAGE
ANNUAL FREQ
139
32
0
30
5
25
2
0
0
0
9
2
1
0
5
1
0
1
1
21
50
8
8
2
2
3
5
3
3
9
1
1
AVG ANNUAL
CRASHES/INT
% OF TOTAL
2.40
0.55
0.00
0.52
0.09
0.43
0.03
0.00
0.00
0.00
0.16
0.03
0.02
0.00
0.09
0.02
0.00
0.02
0.02
0.36
0.86
0.14
0.14
0.03
0.03
0.05
0.09
0.05
0.05
0.16
0.02
0.02
100.0%
23.0%
0.0%
21.6%
3.6%
18.0%
1.4%
0.0%
0.0%
0.0%
6.5%
1.4%
0.7%
0.0%
3.6%
0.7%
0.0%
0.7%
0.7%
15.1%
36.0%
5.8%
5.8%
1.4%
1.4%
2.2%
3.6%
2.2%
2.2%
6.5%
0.7%
0.7%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
2
2004-2006 2 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
12,792
TOT INTERSECTIONS = 211
AVERAGE
ANNUAL FREQ
301
74
2
57
25
54
6
4
0
0
14
7
1
2
18
1
0
3
3
32
113
15
18
16
6
4
9
11
8
10
0
1
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.43
0.35
0.01
0.27
0.12
0.26
0.03
0.02
0.00
0.00
0.07
0.03
0.00
0.01
0.09
0.00
0.00
0.01
0.01
0.15
0.54
0.07
0.09
0.08
0.03
0.02
0.04
0.05
0.04
0.05
0.00
0.00
100.0%
24.6%
0.7%
18.9%
8.3%
17.9%
2.0%
1.3%
0.0%
0.0%
4.7%
2.3%
0.3%
0.7%
6.0%
0.3%
0.0%
1.0%
1.0%
10.6%
37.5%
5.0%
6.0%
5.3%
2.0%
1.3%
3.0%
3.7%
2.7%
3.3%
0.0%
0.3%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
3
2004-2006 2 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
13,731
TOT INTERSECTIONS = 12
AVERAGE
ANNUAL FREQ
AVG ANNUAL
CRASHES/INT
% OF TOTAL
59
14
1
13
5
15
0
0
0
0
3
0
0
0
1
0
0
0
0
11
28
3
2
0
1
0
2
1
1
3
0
0
4.92
1.17
0.08
1.08
0.42
1.25
0.00
0.00
0.00
0.00
0.25
0.00
0.00
0.00
0.08
0.00
0.00
0.00
0.00
0.92
2.33
0.25
0.17
0.00
0.08
0.00
0.17
0.08
0.08
0.25
0.00
0.00
100.0%
23.7%
1.7%
22.0%
8.5%
25.4%
0.0%
0.0%
0.0%
0.0%
5.1%
0.0%
0.0%
0.0%
1.7%
0.0%
0.0%
0.0%
0.0%
18.6%
47.5%
5.1%
3.4%
0.0%
1.7%
0.0%
3.4%
1.7%
1.7%
5.1%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
4
2004-2006 2 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
22,362
TOT INTERSECTIONS = 2
AVERAGE
ANNUAL FREQ
3
0
0
0
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
2
0
0
0
0
0
0
0
0
0
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.50
0.00
0.00
0.00
0.00
0.50
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.50
0.00
0.00
0.00
0.00
0.00
1.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
100.0%
0.0%
0.0%
0.0%
0.0%
33.3%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
33.3%
0.0%
0.0%
0.0%
0.0%
0.0%
66.7%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
5
2004-2006 2 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
22,362
TOT INTERSECTIONS = 1
AVERAGE
ANNUAL FREQ
5
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
1
0
1
0
0
0
0
0
0
0
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
5.00
0.00
0.00
1.00
0.00
0.00
0.00
0.00
0.00
0.00
1.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.00
1.00
0.00
1.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
100.0%
0.0%
0.0%
20.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
20.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
20.0%
20.0%
0.0%
20.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
6
2004-2006 3 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
5,949
TOT INTERSECTIONS = 132
AVERAGE
ANNUAL FREQ
89
22
0
17
5
19
1
0
0
1
8
4
1
1
5
1
0
1
1
15
17
7
7
3
3
1
3
1
2
5
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
0.67
0.17
0.00
0.13
0.04
0.14
0.01
0.00
0.00
0.01
0.06
0.03
0.01
0.01
0.04
0.01
0.00
0.01
0.01
0.11
0.13
0.05
0.05
0.02
0.02
0.01
0.02
0.01
0.02
0.04
0.00
0.00
100.0%
24.7%
0.0%
19.1%
5.6%
21.3%
1.1%
0.0%
0.0%
1.1%
9.0%
4.5%
1.1%
1.1%
5.6%
1.1%
0.0%
1.1%
1.1%
16.9%
19.1%
7.9%
7.9%
3.4%
3.4%
1.1%
3.4%
1.1%
2.2%
5.6%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
7
2004-2006 3 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
6,837
TOT INTERSECTIONS = 9
AVERAGE
ANNUAL FREQ
17
2
0
2
2
5
0
0
0
0
1
1
0
0
1
0
0
0
0
5
6
0
1
0
0
0
0
1
1
2
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.89
0.22
0.00
0.22
0.22
0.56
0.00
0.00
0.00
0.00
0.11
0.11
0.00
0.00
0.11
0.00
0.00
0.00
0.00
0.56
0.67
0.00
0.11
0.00
0.00
0.00
0.00
0.11
0.11
0.22
0.00
0.00
100.0%
11.8%
0.0%
11.8%
11.8%
29.4%
0.0%
0.0%
0.0%
0.0%
5.9%
5.9%
0.0%
0.0%
5.9%
0.0%
0.0%
0.0%
0.0%
29.4%
35.3%
0.0%
5.9%
0.0%
0.0%
0.0%
0.0%
5.9%
5.9%
11.8%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
8
2004-2006 3 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
13,216
TOT INTERSECTIONS = 82
AVERAGE
ANNUAL FREQ
125
24
1
20
6
27
2
0
0
1
8
4
1
1
9
2
0
1
2
19
31
11
10
3
1
2
6
4
3
3
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.52
0.29
0.01
0.24
0.07
0.33
0.02
0.00
0.00
0.01
0.10
0.05
0.01
0.01
0.11
0.02
0.00
0.01
0.02
0.23
0.38
0.13
0.12
0.04
0.01
0.02
0.07
0.05
0.04
0.04
0.00
0.00
100.0%
19.2%
0.8%
16.0%
4.8%
21.6%
1.6%
0.0%
0.0%
0.8%
6.4%
3.2%
0.8%
0.8%
7.2%
1.6%
0.0%
0.8%
1.6%
15.2%
24.8%
8.8%
8.0%
2.4%
0.8%
1.6%
4.8%
3.2%
2.4%
2.4%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
9
2004-2006 3 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
14,035
TOT INTERSECTIONS = 8
AVERAGE
ANNUAL FREQ
45
9
0
7
2
6
0
0
0
0
1
0
0
1
1
0
0
0
0
6
22
2
4
1
1
0
1
2
0
2
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
5.63
1.13
0.00
0.88
0.25
0.75
0.00
0.00
0.00
0.00
0.13
0.00
0.00
0.13
0.13
0.00
0.00
0.00
0.00
0.75
2.75
0.25
0.50
0.13
0.13
0.00
0.13
0.25
0.00
0.25
0.00
0.00
100.0%
20.0%
0.0%
15.6%
4.4%
13.3%
0.0%
0.0%
0.0%
0.0%
2.2%
0.0%
0.0%
2.2%
2.2%
0.0%
0.0%
0.0%
0.0%
13.3%
48.9%
4.4%
8.9%
2.2%
2.2%
0.0%
2.2%
4.4%
0.0%
4.4%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
10
2004-2006 3 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
21,663
TOT INTERSECTIONS = 16
AVERAGE
ANNUAL FREQ
29
6
0
8
1
4
0
0
0
0
1
0
0
0
2
0
0
0
0
2
15
1
2
0
1
0
0
3
1
1
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.81
0.38
0.00
0.50
0.06
0.25
0.00
0.00
0.00
0.00
0.06
0.00
0.00
0.00
0.13
0.00
0.00
0.00
0.00
0.13
0.94
0.06
0.13
0.00
0.06
0.00
0.00
0.19
0.06
0.06
0.00
0.00
100.0%
20.7%
0.0%
27.6%
3.4%
13.8%
0.0%
0.0%
0.0%
0.0%
3.4%
0.0%
0.0%
0.0%
6.9%
0.0%
0.0%
0.0%
0.0%
6.9%
51.7%
3.4%
6.9%
0.0%
3.4%
0.0%
0.0%
10.3%
3.4%
3.4%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
11
2004-2006 3 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
SUPERIOR AND NORTH REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
21,464
TOT INTERSECTIONS = 2
AVERAGE
ANNUAL FREQ
11
3
0
4
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
1
8
1
0
0
0
0
0
1
0
0
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
5.50
1.50
0.00
2.00
0.00
0.50
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.50
4.00
0.50
0.00
0.00
0.00
0.00
0.00
0.50
0.00
0.00
0.00
0.00
100.0%
27.3%
0.0%
36.4%
0.0%
9.1%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
9.1%
72.7%
9.1%
0.0%
0.0%
0.0%
0.0%
0.0%
9.1%
0.0%
0.0%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
12
2004-2006 4 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
7,008
TOT INTERSECTIONS = 244
AVERAGE
ANNUAL FREQ
145
35
0
23
6
29
4
1
0
1
13
6
1
1
17
1
0
1
1
26
19
10
18
5
2
1
5
1
3
8
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
0.59
0.14
0.00
0.09
0.02
0.12
0.02
0.00
0.00
0.00
0.05
0.02
0.00
0.00
0.07
0.00
0.00
0.00
0.00
0.11
0.08
0.04
0.07
0.02
0.01
0.00
0.02
0.00
0.01
0.03
0.00
0.00
100.0%
24.1%
0.0%
15.9%
4.1%
20.0%
2.8%
0.7%
0.0%
0.7%
9.0%
4.1%
0.7%
0.7%
11.7%
0.7%
0.0%
0.7%
0.7%
17.9%
13.1%
6.9%
12.4%
3.4%
1.4%
0.7%
3.4%
0.7%
2.1%
5.5%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
13
2004-2006 4 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
8,263
TOT INTERSECTIONS = 13
AVERAGE
ANNUAL FREQ
40
11
0
7
1
8
1
0
0
0
2
0
0
0
2
0
0
0
0
8
13
4
2
1
1
0
0
1
1
3
0
1
AVG ANNUAL
CRASHES/INT
% OF TOTAL
3.08
0.85
0.00
0.54
0.08
0.62
0.08
0.00
0.00
0.00
0.15
0.00
0.00
0.00
0.15
0.00
0.00
0.00
0.00
0.62
1.00
0.31
0.15
0.08
0.08
0.00
0.00
0.08
0.08
0.23
0.00
0.08
100.0%
27.5%
0.0%
17.5%
2.5%
20.0%
2.5%
0.0%
0.0%
0.0%
5.0%
0.0%
0.0%
0.0%
5.0%
0.0%
0.0%
0.0%
0.0%
20.0%
32.5%
10.0%
5.0%
2.5%
2.5%
0.0%
0.0%
2.5%
2.5%
7.5%
0.0%
2.5%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
14
2004-2006 4 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
14,306
TOT INTERSECTIONS = 259
AVERAGE
ANNUAL FREQ
451
105
1
91
13
67
8
0
0
1
20
14
3
4
26
4
0
5
4
57
114
43
48
26
5
5
15
18
12
20
0
1
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.74
0.41
0.00
0.35
0.05
0.26
0.03
0.00
0.00
0.00
0.08
0.05
0.01
0.02
0.10
0.02
0.00
0.02
0.02
0.22
0.44
0.17
0.19
0.10
0.02
0.02
0.06
0.07
0.05
0.08
0.00
0.00
100.0%
23.3%
0.2%
20.2%
2.9%
14.9%
1.8%
0.0%
0.0%
0.2%
4.4%
3.1%
0.7%
0.9%
5.8%
0.9%
0.0%
1.1%
0.9%
12.6%
25.3%
9.5%
10.6%
5.8%
1.1%
1.1%
3.3%
4.0%
2.7%
4.4%
0.0%
0.2%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
15
2004-2006 4 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
15,384
TOT INTERSECTIONS = 35
AVERAGE
ANNUAL FREQ
240
53
0
51
10
41
2
0
0
1
8
4
1
2
6
0
0
7
2
41
85
20
21
6
4
1
6
8
4
11
0
1
AVG ANNUAL
CRASHES/INT
% OF TOTAL
6.86
1.51
0.00
1.46
0.29
1.17
0.06
0.00
0.00
0.03
0.23
0.11
0.03
0.06
0.17
0.00
0.00
0.20
0.06
1.17
2.43
0.57
0.60
0.17
0.11
0.03
0.17
0.23
0.11
0.31
0.00
0.03
100.0%
22.1%
0.0%
21.3%
4.2%
17.1%
0.8%
0.0%
0.0%
0.4%
3.3%
1.7%
0.4%
0.8%
2.5%
0.0%
0.0%
2.9%
0.8%
17.1%
35.4%
8.3%
8.8%
2.5%
1.7%
0.4%
2.5%
3.3%
1.7%
4.6%
0.0%
0.4%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
16
2004-2006 4 LANE
Average
ADT
NORTH
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
2 WAY UNSIGNALIZED INTERSECTIONS
Annual Crash Frequency
GREATER THAN 20,000
AND SUPERIOR REGIONS
23,692
TOT INTERSECTIONS = 34
AVERAGE
ANNUAL FREQ
164
31
0
39
7
26
2
0
0
0
3
3
1
0
9
0
0
1
1
14
63
17
22
7
2
0
6
7
4
3
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
4.82
0.91
0.00
1.15
0.21
0.76
0.06
0.00
0.00
0.00
0.09
0.09
0.03
0.00
0.26
0.00
0.00
0.03
0.03
0.41
1.85
0.50
0.65
0.21
0.06
0.00
0.18
0.21
0.12
0.09
0.00
0.00
100.0%
18.9%
0.0%
23.8%
4.3%
15.9%
1.2%
0.0%
0.0%
0.0%
1.8%
1.8%
0.6%
0.0%
5.5%
0.0%
0.0%
0.6%
0.6%
8.5%
38.4%
10.4%
13.4%
4.3%
1.2%
0.0%
3.7%
4.3%
2.4%
1.8%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
17
2004-2006 4 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
25,169
TOT INTERSECTIONS = 5
AVERAGE
ANNUAL FREQ
53
9
0
14
1
9
0
0
0
0
1
1
0
1
2
0
0
1
1
7
20
3
5
0
1
0
3
4
1
2
1
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
10.60
1.80
0.00
2.80
0.20
1.80
0.00
0.00
0.00
0.00
0.20
0.20
0.00
0.20
0.40
0.00
0.00
0.20
0.20
1.40
4.00
0.60
1.00
0.00
0.20
0.00
0.60
0.80
0.20
0.40
0.20
0.00
100.0%
17.0%
0.0%
26.4%
1.9%
17.0%
0.0%
0.0%
0.0%
0.0%
1.9%
1.9%
0.0%
1.9%
3.8%
0.0%
0.0%
1.9%
1.9%
13.2%
37.7%
5.7%
9.4%
0.0%
1.9%
0.0%
5.7%
7.5%
1.9%
3.8%
1.9%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
18
2004-2006 5 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
7,829
TOT INTERSECTIONS = 60
AVERAGE
ANNUAL FREQ
34
12
0
5
3
8
2
1
0
0
2
1
1
0
4
0
0
0
1
9
3
2
3
1
1
0
1
1
0
2
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
0.57
0.20
0.00
0.08
0.05
0.13
0.03
0.02
0.00
0.00
0.03
0.02
0.02
0.00
0.07
0.00
0.00
0.00
0.02
0.15
0.05
0.03
0.05
0.02
0.02
0.00
0.02
0.02
0.00
0.03
0.00
0.00
100.0%
35.3%
0.0%
14.7%
8.8%
23.5%
5.9%
2.9%
0.0%
0.0%
5.9%
2.9%
2.9%
0.0%
11.8%
0.0%
0.0%
0.0%
2.9%
26.5%
8.8%
5.9%
8.8%
2.9%
2.9%
0.0%
2.9%
2.9%
0.0%
5.9%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
19
2004-2006 5 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
8,955
TOT INTERSECTIONS = 1
AVERAGE
ANNUAL FREQ
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
100.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
100.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
20
2004-2006 5 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
14,930
TOT INTERSECTIONS = 177
AVERAGE
ANNUAL FREQ
340
87
1
73
19
71
4
2
0
1
11
10
1
3
15
2
0
5
4
62
75
35
45
7
5
5
17
8
9
14
1
1
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.92
0.49
0.01
0.41
0.11
0.40
0.02
0.01
0.00
0.01
0.06
0.06
0.01
0.02
0.08
0.01
0.00
0.03
0.02
0.35
0.42
0.20
0.25
0.04
0.03
0.03
0.10
0.05
0.05
0.08
0.01
0.01
100.0%
25.6%
0.3%
21.5%
5.6%
20.9%
1.2%
0.6%
0.0%
0.3%
3.2%
2.9%
0.3%
0.9%
4.4%
0.6%
0.0%
1.5%
1.2%
18.2%
22.1%
10.3%
13.2%
2.1%
1.5%
1.5%
5.0%
2.4%
2.6%
4.1%
0.3%
0.3%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
21
2004-2006 5 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
14,132
TOT INTERSECTIONS = 20
AVERAGE
ANNUAL FREQ
134
30
0
26
6
24
0
0
0
0
5
3
1
0
3
1
0
2
1
24
40
11
12
2
2
2
9
2
4
9
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
6.70
1.50
0.00
1.30
0.30
1.20
0.00
0.00
0.00
0.00
0.25
0.15
0.05
0.00
0.15
0.05
0.00
0.10
0.05
1.20
2.00
0.55
0.60
0.10
0.10
0.10
0.45
0.10
0.20
0.45
0.00
0.00
100.0%
22.4%
0.0%
19.4%
4.5%
17.9%
0.0%
0.0%
0.0%
0.0%
3.7%
2.2%
0.7%
0.0%
2.2%
0.7%
0.0%
1.5%
0.7%
17.9%
29.9%
8.2%
9.0%
1.5%
1.5%
1.5%
6.7%
1.5%
3.0%
6.7%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
22
2004-2006 5 LANE
Average
ADT
NORTH
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
2 WAY UNSIGNALIZED INTERSECTIONS
Annual Crash Frequency
GREATER THAN 20,000
AND SUPERIOR REGIONS
24,187
TOT INTERSECTIONS = 90
AVERAGE
ANNUAL FREQ
283
58
1
68
13
51
3
2
0
0
10
3
2
1
16
4
0
0
4
29
100
27
30
2
4
2
14
10
8
11
0
1
AVG ANNUAL
CRASHES/INT
% OF TOTAL
3.14
0.64
0.01
0.76
0.14
0.57
0.03
0.02
0.00
0.00
0.11
0.03
0.02
0.01
0.18
0.04
0.00
0.00
0.04
0.32
1.11
0.30
0.33
0.02
0.04
0.02
0.16
0.11
0.09
0.12
0.00
0.01
100.0%
20.5%
0.4%
24.0%
4.6%
18.0%
1.1%
0.7%
0.0%
0.0%
3.5%
1.1%
0.7%
0.4%
5.7%
1.4%
0.0%
0.0%
1.4%
10.2%
35.3%
9.5%
10.6%
0.7%
1.4%
0.7%
4.9%
3.5%
2.8%
3.9%
0.0%
0.4%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
23
2004-2006 5 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
25,504
TOT INTERSECTIONS = 26
AVERAGE
ANNUAL FREQ
335
66
0
77
19
69
3
1
0
0
9
3
2
1
8
1
0
1
2
31
144
21
25
8
6
4
25
15
5
16
4
2
AVG ANNUAL
CRASHES/INT
% OF TOTAL
12.88
2.54
0.00
2.96
0.73
2.65
0.12
0.04
0.00
0.00
0.35
0.12
0.08
0.04
0.31
0.04
0.00
0.04
0.08
1.19
5.54
0.81
0.96
0.31
0.23
0.15
0.96
0.58
0.19
0.62
0.15
0.08
100.0%
19.7%
0.0%
23.0%
5.7%
20.6%
0.9%
0.3%
0.0%
0.0%
2.7%
0.9%
0.6%
0.3%
2.4%
0.3%
0.0%
0.3%
0.6%
9.3%
43.0%
6.3%
7.5%
2.4%
1.8%
1.2%
7.5%
4.5%
1.5%
4.8%
1.2%
0.6%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
24
2004-2006 7 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOT INTERSECTIONS =
AVERAGE
ANNUAL FREQ
AVG ANNUAL
CRASHES/INT
% OF TOTAL
NO LOCATIONS
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
25
2004-2006 7 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOT INTERSECTIONS =
AVERAGE
ANNUAL FREQ
AVG ANNUAL
CRASHES/INT
% OF TOTAL
NO LOCATIONS
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
26
2004-2006 7 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOT INTERSECTIONS =
AVERAGE
ANNUAL FREQ
AVG ANNUAL
CRASHES/INT
% OF TOTAL
NO LOCATIONS
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
27
2004-2006 7 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOT INTERSECTIONS =
AVERAGE
ANNUAL FREQ
AVG ANNUAL
CRASHES/INT
% OF TOTAL
NO LOCATIONS
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
28
2004-2006 7 LANE
Average
ADT
NORTH
AVG ADT =
CRASH TYPE
2 WAY UNSIGNALIZED INTERSECTIONS
Annual Crash Frequency
GREATER THAN 20,000
AND SUPERIOR REGIONS
TOT INTERSECTIONS =
AVERAGE
ANNUAL FREQ
AVG ANNUAL
CRASHES/INT
% OF TOTAL
NO LOCATIONS
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
29
2004-2006 7 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT =
CRASH TYPE
TOT INTERSECTIONS =
AVERAGE
ANNUAL FREQ
AVG ANNUAL
CRASHES/INT
% OF TOTAL
NO LOCATIONS
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
30
2004-2006 DIVIDED ROAD UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
NORTH AND SUPERIOR REGIONS
AVG ADT = 5,120
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 15
AVERAGE
ANNUAL FREQ
3
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
0.20
0.00
0.00
0.07
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.07
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
100.0%
0.0%
0.0%
33.3%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
33.3%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
31
2004-2006 DIVIDED ROAD SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
NORTH AND SUPERIOR REGIONS
AVG ADT = 5,160
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 2
AVERAGE
ANNUAL FREQ
1
1
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
0.50
0.50
0.00
0.00
0.00
0.50
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
100.0%
100.0%
0.0%
0.0%
0.0%
100.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
32
2004-2006 DIVIDED ROAD UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT = 14,412
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 37
AVERAGE
ANNUAL FREQ
73
20
0
14
5
17
2
1
0
0
3
1
0
1
7
1
0
1
1
18
20
3
8
1
3
0
0
1
2
2
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.97
0.54
0.00
0.38
0.14
0.46
0.05
0.03
0.00
0.00
0.08
0.03
0.00
0.03
0.19
0.03
0.00
0.03
0.03
0.49
0.54
0.08
0.22
0.03
0.08
0.00
0.00
0.03
0.05
0.05
0.00
0.00
100.0%
27.4%
0.0%
19.2%
6.8%
23.3%
2.7%
1.4%
0.0%
0.0%
4.1%
1.4%
0.0%
1.4%
9.6%
1.4%
0.0%
1.4%
1.4%
24.7%
27.4%
4.1%
11.0%
1.4%
4.1%
0.0%
0.0%
1.4%
2.7%
2.7%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
33
2004-2006 DIVIDED ROAD SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT = 14,407
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 5
AVERAGE
ANNUAL FREQ
22
5
0
5
1
5
0
0
0
0
0
0
0
0
1
1
0
0
0
5
10
0
1
0
3
0
0
1
0
0
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
4.40
1.00
0.00
1.00
0.20
1.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.20
0.20
0.00
0.00
0.00
1.00
2.00
0.00
0.20
0.00
0.60
0.00
0.00
0.20
0.00
0.00
0.00
0.00
100.0%
22.7%
0.0%
22.7%
4.5%
22.7%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
4.5%
4.5%
0.0%
0.0%
0.0%
22.7%
45.5%
0.0%
4.5%
0.0%
13.6%
0.0%
0.0%
4.5%
0.0%
0.0%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
34
2004-2006 DIVIDED ROAD UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT = 29,250
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 34
AVERAGE
ANNUAL FREQ
105
25
0
17
4
15
0
0
0
0
6
1
1
0
2
2
0
1
0
13
48
4
8
2
5
1
2
4
2
1
0
1
AVG ANNUAL
CRASHES/INT
% OF TOTAL
3.09
0.74
0.00
0.50
0.12
0.44
0.00
0.00
0.00
0.00
0.18
0.03
0.03
0.00
0.06
0.06
0.00
0.03
0.00
0.38
1.41
0.12
0.24
0.06
0.15
0.03
0.06
0.12
0.06
0.03
0.00
0.03
100.0%
23.8%
0.0%
16.2%
3.8%
14.3%
0.0%
0.0%
0.0%
0.0%
5.7%
1.0%
1.0%
0.0%
1.9%
1.9%
0.0%
1.0%
0.0%
12.4%
45.7%
3.8%
7.6%
1.9%
4.8%
1.0%
1.9%
3.8%
1.9%
1.0%
0.0%
1.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
35
2004-2006 DIVIDED ROAD SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
NORTH AND SUPERIOR REGIONS
AVG ADT = 25,825
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 6
AVERAGE
ANNUAL FREQ
29
6
0
5
0
4
0
0
0
0
1
1
0
0
2
0
0
0
0
3
13
1
4
0
0
0
0
2
1
1
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
4.83
1.00
0.00
0.83
0.00
0.67
0.00
0.00
0.00
0.00
0.17
0.17
0.00
0.00
0.33
0.00
0.00
0.00
0.00
0.50
2.17
0.17
0.67
0.00
0.00
0.00
0.00
0.33
0.17
0.17
0.00
0.00
100.0%
20.7%
0.0%
17.2%
0.0%
13.8%
0.0%
0.0%
0.0%
0.0%
3.4%
3.4%
0.0%
0.0%
6.9%
0.0%
0.0%
0.0%
0.0%
10.3%
44.8%
3.4%
13.8%
0.0%
0.0%
0.0%
0.0%
6.9%
3.4%
3.4%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
36
2004-2006 2 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
5,030
TOT INTERSECTIONS = 5,202
AVERAGE
ANNUAL FREQ
2996
914
28
511
174
807
77
71
0
6
184
67
8
15
505
30
0
12
52
568
555
164
169
132
56
19
44
53
86
107
2
12
AVG ANNUAL
CRASHES/INT
% OF TOTAL
0.58
0.18
0.01
0.10
0.03
0.16
0.01
0.01
0.00
0.00
0.04
0.01
0.00
0.00
0.10
0.01
0.00
0.00
0.01
0.11
0.11
0.03
0.03
0.03
0.01
0.00
0.01
0.01
0.02
0.02
0.00
0.00
100.0%
30.5%
0.9%
17.1%
5.8%
26.9%
2.6%
2.4%
0.0%
0.2%
6.1%
2.2%
0.3%
0.5%
16.9%
1.0%
0.0%
0.4%
1.7%
19.0%
18.5%
5.5%
5.6%
4.4%
1.9%
0.6%
1.5%
1.8%
2.9%
3.6%
0.1%
0.4%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
37
2004-2006 2 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
6,649
TOT INTERSECTIONS = 112
AVERAGE
ANNUAL FREQ
318
72
1
68
6
90
4
2
0
0
15
9
3
3
14
2
0
4
2
51
90
17
29
7
5
4
13
7
10
22
1
3
AVG ANNUAL
CRASHES/INT
% OF TOTAL
2.84
0.64
0.01
0.61
0.05
0.80
0.04
0.02
0.00
0.00
0.13
0.08
0.03
0.03
0.13
0.02
0.00
0.04
0.02
0.46
0.80
0.15
0.26
0.06
0.04
0.04
0.12
0.06
0.09
0.20
0.01
0.03
100.0%
22.6%
0.3%
21.4%
1.9%
28.3%
1.3%
0.6%
0.0%
0.0%
4.7%
2.8%
0.9%
0.9%
4.4%
0.6%
0.0%
1.3%
0.6%
16.0%
28.3%
5.3%
9.1%
2.2%
1.6%
1.3%
4.1%
2.2%
3.1%
6.9%
0.3%
0.9%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
38
2004-2006 2 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
13,536
TOT INTERSECTIONS = 911
AVERAGE
ANNUAL FREQ
1486
410
8
311
59
371
18
16
0
2
74
26
3
7
140
11
0
9
24
180
500
99
84
63
23
16
33
51
40
58
2
7
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.63
0.45
0.01
0.34
0.06
0.41
0.02
0.02
0.00
0.00
0.08
0.03
0.00
0.01
0.15
0.01
0.00
0.01
0.03
0.20
0.55
0.11
0.09
0.07
0.03
0.02
0.04
0.06
0.04
0.06
0.00
0.01
100.0%
27.6%
0.5%
20.9%
4.0%
25.0%
1.2%
1.1%
0.0%
0.1%
5.0%
1.7%
0.2%
0.5%
9.4%
0.7%
0.0%
0.6%
1.6%
12.1%
33.6%
6.7%
5.7%
4.2%
1.5%
1.1%
2.2%
3.4%
2.7%
3.9%
0.1%
0.5%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
39
2004-2006 2 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
14,840
TOT INTERSECTIONS = 87
AVERAGE
ANNUAL FREQ
682
159
1
150
9
165
6
1
0
1
32
15
4
5
21
1
0
4
8
80
252
36
49
8
10
9
31
30
19
51
3
4
AVG ANNUAL
CRASHES/INT
% OF TOTAL
7.84
1.83
0.01
1.72
0.10
1.90
0.07
0.01
0.00
0.01
0.37
0.17
0.05
0.06
0.24
0.01
0.00
0.05
0.09
0.92
2.90
0.41
0.56
0.09
0.11
0.10
0.36
0.34
0.22
0.59
0.03
0.05
100.0%
23.3%
0.1%
22.0%
1.3%
24.2%
0.9%
0.1%
0.0%
0.1%
4.7%
2.2%
0.6%
0.7%
3.1%
0.1%
0.0%
0.6%
1.2%
11.7%
37.0%
5.3%
7.2%
1.2%
1.5%
1.3%
4.5%
4.4%
2.8%
7.5%
0.4%
0.6%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
40
2004-2006 2 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
22,427
TOT INTERSECTIONS = 56
AVERAGE
ANNUAL FREQ
127
32
1
31
6
37
1
1
0
0
7
2
1
1
10
3
0
0
3
13
43
10
9
3
2
2
3
4
3
6
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
2.27
0.57
0.02
0.55
0.11
0.66
0.02
0.02
0.00
0.00
0.13
0.04
0.02
0.02
0.18
0.05
0.00
0.00
0.05
0.23
0.77
0.18
0.16
0.05
0.04
0.04
0.05
0.07
0.05
0.11
0.00
0.00
100.0%
25.2%
0.8%
24.4%
4.7%
29.1%
0.8%
0.8%
0.0%
0.0%
5.5%
1.6%
0.8%
0.8%
7.9%
2.4%
0.0%
0.0%
2.4%
10.2%
33.9%
7.9%
7.1%
2.4%
1.6%
1.6%
2.4%
3.1%
2.4%
4.7%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
41
2004-2006 2 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
22,084
TOT INTERSECTIONS = 5
AVERAGE
ANNUAL FREQ
50
9
0
11
2
12
0
0
0
0
1
0
0
0
2
0
0
0
1
6
18
6
4
0
0
2
5
2
1
1
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
10.00
1.80
0.00
2.20
0.40
2.40
0.00
0.00
0.00
0.00
0.20
0.00
0.00
0.00
0.40
0.00
0.00
0.00
0.20
1.20
3.60
1.20
0.80
0.00
0.00
0.40
1.00
0.40
0.20
0.20
0.00
0.00
100.0%
18.0%
0.0%
22.0%
4.0%
24.0%
0.0%
0.0%
0.0%
0.0%
2.0%
0.0%
0.0%
0.0%
4.0%
0.0%
0.0%
0.0%
2.0%
12.0%
36.0%
12.0%
8.0%
0.0%
0.0%
4.0%
10.0%
4.0%
2.0%
2.0%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
42
2004-2006 3 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
7,189
TOT INTERSECTIONS = 485
AVERAGE
ANNUAL FREQ
370
80
0
70
11
78
6
1
0
2
27
19
3
4
29
2
0
5
4
62
96
26
23
4
5
3
11
12
8
16
2
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
0.76
0.16
0.00
0.14
0.02
0.16
0.01
0.00
0.00
0.00
0.06
0.04
0.01
0.01
0.06
0.00
0.00
0.01
0.01
0.13
0.20
0.05
0.05
0.01
0.01
0.01
0.02
0.02
0.02
0.03
0.00
0.00
100.0%
21.6%
0.0%
18.9%
3.0%
21.1%
1.6%
0.3%
0.0%
0.5%
7.3%
5.1%
0.8%
1.1%
7.8%
0.5%
0.0%
1.4%
1.1%
16.8%
25.9%
7.0%
6.2%
1.1%
1.4%
0.8%
3.0%
3.2%
2.2%
4.3%
0.5%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
43
2004-2006 3 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
7,413
TOT INTERSECTIONS = 40
AVERAGE
ANNUAL FREQ
125
31
0
24
3
32
1
0
0
0
10
5
2
2
8
0
0
2
1
22
33
6
7
2
2
3
3
5
4
9
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
3.13
0.77
0.00
0.60
0.08
0.80
0.03
0.00
0.00
0.00
0.25
0.13
0.05
0.05
0.20
0.00
0.00
0.05
0.03
0.55
0.82
0.15
0.17
0.05
0.05
0.08
0.08
0.13
0.10
0.22
0.00
0.00
100.0%
24.8%
0.0%
19.2%
2.4%
25.6%
0.8%
0.0%
0.0%
0.0%
8.0%
4.0%
1.6%
1.6%
6.4%
0.0%
0.0%
1.6%
0.8%
17.6%
26.4%
4.8%
5.6%
1.6%
1.6%
2.4%
2.4%
4.0%
3.2%
7.2%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
44
2004-2006 3 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
13,553
TOT INTERSECTIONS = 485
AVERAGE
ANNUAL FREQ
767
189
2
155
25
154
9
2
0
1
33
21
6
6
52
5
0
13
10
94
279
51
51
13
9
8
28
30
16
25
2
4
AVG ANNUAL
CRASHES/INT
1.58
0.39
0.00
0.32
0.05
0.32
0.02
0.00
0.00
0.00
0.07
0.04
0.01
0.01
0.11
0.01
0.00
0.03
0.02
0.19
0.58
0.11
0.11
0.03
0.02
0.02
0.06
0.06
0.03
0.05
0.00
0.01
% OF TOTAL
100.0%
24.6%
0.3%
20.2%
3.3%
20.1%
1.2%
0.3%
0.0%
0.1%
4.3%
2.7%
0.8%
0.8%
6.8%
0.7%
0.0%
1.7%
1.3%
12.3%
36.4%
6.6%
6.6%
1.7%
1.2%
1.0%
3.7%
3.9%
2.1%
3.3%
0.3%
0.5%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
45
2004-2006 3 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 to 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
13,961
TOT INTERSECTIONS = 77
AVERAGE
ANNUAL FREQ
446
97
0
89
12
90
4
0
0
0
20
9
3
5
16
1
0
5
6
46
184
24
33
3
6
6
20
19
9
23
1
3
AVG ANNUAL
CRASHES/INT
% OF TOTAL
5.79
1.26
0.00
1.16
0.16
1.17
0.05
0.00
0.00
0.00
0.26
0.12
0.04
0.06
0.21
0.01
0.00
0.06
0.08
0.60
2.39
0.31
0.43
0.04
0.08
0.08
0.26
0.25
0.12
0.30
0.01
0.04
100.0%
21.7%
0.0%
20.0%
2.7%
20.2%
0.9%
0.0%
0.0%
0.0%
4.5%
2.0%
0.7%
1.1%
3.6%
0.2%
0.0%
1.1%
1.3%
10.3%
41.3%
5.4%
7.4%
0.7%
1.3%
1.3%
4.5%
4.3%
2.0%
5.2%
0.2%
0.7%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
46
2004-2006 3 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
22,005
TOT INTERSECTIONS = 23
AVERAGE
ANNUAL FREQ
46
8
0
9
1
10
1
0
0
0
1
1
0
0
4
1
0
0
0
3
23
2
2
1
0
1
1
1
0
2
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
2.00
0.35
0.00
0.39
0.04
0.43
0.04
0.00
0.00
0.00
0.04
0.04
0.00
0.00
0.17
0.04
0.00
0.00
0.00
0.13
1.00
0.09
0.09
0.04
0.00
0.04
0.04
0.04
0.00
0.09
0.00
0.00
100.0%
17.4%
0.0%
19.6%
2.2%
21.7%
2.2%
0.0%
0.0%
0.0%
2.2%
2.2%
0.0%
0.0%
8.7%
2.2%
0.0%
0.0%
0.0%
6.5%
50.0%
4.3%
4.3%
2.2%
0.0%
2.2%
2.2%
2.2%
0.0%
4.3%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
47
2004-2006 3 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
22,849
TOT INTERSECTIONS = 7
AVERAGE
ANNUAL FREQ
50
12
0
10
2
14
0
0
0
0
1
0
0
1
1
0
0
0
0
4
24
2
5
1
1
0
3
1
0
5
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
7.14
1.71
0.00
1.43
0.29
2.00
0.00
0.00
0.00
0.00
0.14
0.00
0.00
0.14
0.14
0.00
0.00
0.00
0.00
0.57
3.43
0.29
0.71
0.14
0.14
0.00
0.43
0.14
0.00
0.71
0.00
0.00
100.0%
24.0%
0.0%
20.0%
4.0%
28.0%
0.0%
0.0%
0.0%
0.0%
2.0%
0.0%
0.0%
2.0%
2.0%
0.0%
0.0%
0.0%
0.0%
8.0%
48.0%
4.0%
10.0%
2.0%
2.0%
0.0%
6.0%
2.0%
0.0%
10.0%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
48
2004-2006 4 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
7,681
TOT INTERSECTIONS = 503
AVERAGE
ANNUAL FREQ
479
108
1
89
16
90
8
2
0
1
29
19
3
7
36
3
0
4
7
79
89
40
54
17
7
9
18
10
12
24
0
1
AVG ANNUAL
CRASHES/INT
% OF TOTAL
0.95
0.21
0.00
0.18
0.03
0.18
0.02
0.00
0.00
0.00
0.06
0.04
0.01
0.01
0.07
0.01
0.00
0.01
0.01
0.16
0.18
0.08
0.11
0.03
0.01
0.02
0.04
0.02
0.02
0.05
0.00
0.00
100.0%
22.5%
0.2%
18.6%
3.3%
18.8%
1.7%
0.4%
0.0%
0.2%
6.1%
4.0%
0.6%
1.5%
7.5%
0.6%
0.0%
0.8%
1.5%
16.5%
18.6%
8.4%
11.3%
3.5%
1.5%
1.9%
3.8%
2.1%
2.5%
5.0%
0.0%
0.2%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
49
2004-2006 4 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
8,064
TOT INTERSECTIONS = 72
AVERAGE
ANNUAL FREQ
307
66
0
57
8
65
4
1
0
1
15
9
4
4
12
1
0
6
4
59
85
22
27
3
3
3
6
8
7
21
2
2
AVG ANNUAL
CRASHES/INT
% OF TOTAL
4.26
0.92
0.00
0.79
0.11
0.90
0.06
0.01
0.00
0.01
0.21
0.13
0.06
0.06
0.17
0.01
0.00
0.08
0.06
0.82
1.18
0.31
0.38
0.04
0.04
0.04
0.08
0.11
0.10
0.29
0.03
0.03
100.0%
21.5%
0.0%
18.6%
2.6%
21.2%
1.3%
0.3%
0.0%
0.3%
4.9%
2.9%
1.3%
1.3%
3.9%
0.3%
0.0%
2.0%
1.3%
19.2%
27.7%
7.2%
8.8%
1.0%
1.0%
1.0%
2.0%
2.6%
2.3%
6.8%
0.7%
0.7%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
50
2004-2006 4 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
14,162
TOT INTERSECTIONS = 706
AVERAGE
ANNUAL FREQ
1385
361
3
293
35
277
13
4
0
1
60
35
5
14
100
9
0
16
18
174
348
134
148
58
9
18
47
56
34
81
1
2
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.96
0.51
0.00
0.42
0.05
0.39
0.02
0.01
0.00
0.00
0.08
0.05
0.01
0.02
0.14
0.01
0.00
0.02
0.03
0.25
0.49
0.19
0.21
0.08
0.01
0.03
0.07
0.08
0.05
0.11
0.00
0.00
100.0%
26.1%
0.2%
21.2%
2.5%
20.0%
0.9%
0.3%
0.0%
0.1%
4.3%
2.5%
0.4%
1.0%
7.2%
0.6%
0.0%
1.2%
1.3%
12.6%
25.1%
9.7%
10.7%
4.2%
0.6%
1.3%
3.4%
4.0%
2.5%
5.8%
0.1%
0.1%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
51
2004-2006 4 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
14,361
TOT INTERSECTIONS = 169
AVERAGE
ANNUAL FREQ
1104
267
1
245
22
241
9
0
0
1
47
31
8
13
39
4
0
14
9
188
331
76
100
20
13
8
39
37
24
83
4
5
AVG ANNUAL
CRASHES/INT
% OF TOTAL
6.53
1.58
0.01
1.45
0.13
1.43
0.05
0.00
0.00
0.01
0.28
0.18
0.05
0.08
0.23
0.02
0.00
0.08
0.05
1.11
1.96
0.45
0.59
0.12
0.08
0.05
0.23
0.22
0.14
0.49
0.02
0.03
100.0%
24.2%
0.1%
22.2%
2.0%
21.8%
0.8%
0.0%
0.0%
0.1%
4.3%
2.8%
0.7%
1.2%
3.5%
0.4%
0.0%
1.3%
0.8%
17.0%
30.0%
6.9%
9.1%
1.8%
1.2%
0.7%
3.5%
3.4%
2.2%
7.5%
0.4%
0.5%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
52
2004-2006 4 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
23,812
TOT INTERSECTIONS = 192
AVERAGE
ANNUAL FREQ
675
156
1
185
12
137
3
1
0
1
21
9
2
4
27
2
0
7
8
69
261
56
65
29
10
9
19
32
13
24
2
2
AVG ANNUAL
CRASHES/INT
% OF TOTAL
3.52
0.81
0.01
0.96
0.06
0.71
0.02
0.01
0.00
0.01
0.11
0.05
0.01
0.02
0.14
0.01
0.00
0.04
0.04
0.36
1.36
0.29
0.34
0.15
0.05
0.05
0.10
0.17
0.07
0.13
0.01
0.01
100.0%
23.1%
0.1%
27.4%
1.8%
20.3%
0.4%
0.1%
0.0%
0.1%
3.1%
1.3%
0.3%
0.6%
4.0%
0.3%
0.0%
1.0%
1.2%
10.2%
38.7%
8.3%
9.6%
4.3%
1.5%
1.3%
2.8%
4.7%
1.9%
3.6%
0.3%
0.3%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
53
2004-2006 4 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
23,170
TOT INTERSECTIONS = 61
AVERAGE
ANNUAL FREQ
640
129
1
164
14
155
3
0
0
0
15
11
2
6
21
2
0
9
6
77
261
37
67
12
9
3
22
29
14
29
4
2
AVG ANNUAL
CRASHES/INT
% OF TOTAL
10.49
2.11
0.02
2.69
0.23
2.54
0.05
0.00
0.00
0.00
0.25
0.18
0.03
0.10
0.34
0.03
0.00
0.15
0.10
1.26
4.28
0.61
1.10
0.20
0.15
0.05
0.36
0.48
0.23
0.48
0.07
0.03
100.0%
20.2%
0.2%
25.6%
2.2%
24.2%
0.5%
0.0%
0.0%
0.0%
2.3%
1.7%
0.3%
0.9%
3.3%
0.3%
0.0%
1.4%
0.9%
12.0%
40.8%
5.8%
10.5%
1.9%
1.4%
0.5%
3.4%
4.5%
2.2%
4.5%
0.6%
0.3%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
54
2004-2006 5 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
8,875
TOT INTERSECTIONS = 99
AVERAGE
ANNUAL FREQ
85
17
0
13
3
19
1
0
0
0
5
2
1
2
11
0
0
0
0
16
10
14
7
0
5
1
2
1
2
4
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
0.86
0.17
0.00
0.13
0.03
0.19
0.01
0.00
0.00
0.00
0.05
0.02
0.01
0.02
0.11
0.00
0.00
0.00
0.00
0.16
0.10
0.14
0.07
0.00
0.05
0.01
0.02
0.01
0.02
0.04
0.00
0.00
100.0%
20.0%
0.0%
15.3%
3.5%
22.4%
1.2%
0.0%
0.0%
0.0%
5.9%
2.4%
1.2%
2.4%
12.9%
0.0%
0.0%
0.0%
0.0%
18.8%
11.8%
16.5%
8.2%
0.0%
5.9%
1.2%
2.4%
1.2%
2.4%
4.7%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
55
2004-2006 5 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
8,957
TOT INTERSECTIONS = 27
AVERAGE
ANNUAL FREQ
93
24
0
18
2
22
2
0
0
0
5
3
0
1
3
1
0
1
1
22
21
5
11
1
2
1
1
2
2
6
0
2
AVG ANNUAL
CRASHES/INT
% OF TOTAL
3.44
0.89
0.00
0.67
0.07
0.81
0.07
0.00
0.00
0.00
0.19
0.11
0.00
0.04
0.11
0.04
0.00
0.04
0.04
0.81
0.78
0.19
0.41
0.04
0.07
0.04
0.04
0.07
0.07
0.22
0.00
0.07
100.0%
25.8%
0.0%
19.4%
2.2%
23.7%
2.2%
0.0%
0.0%
0.0%
5.4%
3.2%
0.0%
1.1%
3.2%
1.1%
0.0%
1.1%
1.1%
23.7%
22.6%
5.4%
11.8%
1.1%
2.2%
1.1%
1.1%
2.2%
2.2%
6.5%
0.0%
2.2%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
56
2004-2006 5 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
15,690
TOT INTERSECTIONS = 718
AVERAGE
ANNUAL FREQ
1352
366
6
269
37
329
13
5
0
9
88
29
10
31
78
8
0
15
21
211
319
129
131
10
20
22
64
33
36
60
4
6
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.88
0.51
0.01
0.37
0.05
0.46
0.02
0.01
0.00
0.01
0.12
0.04
0.01
0.04
0.11
0.01
0.00
0.02
0.03
0.29
0.44
0.18
0.18
0.01
0.03
0.03
0.09
0.05
0.05
0.08
0.01
0.01
100.0%
27.1%
0.4%
19.9%
2.7%
24.3%
1.0%
0.4%
0.0%
0.7%
6.5%
2.1%
0.7%
2.3%
5.8%
0.6%
0.0%
1.1%
1.6%
15.6%
23.6%
9.5%
9.7%
0.7%
1.5%
1.6%
4.7%
2.4%
2.7%
4.4%
0.3%
0.4%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
57
2004-2006 5 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
15,616
TOT INTERSECTIONS = 183
AVERAGE
ANNUAL FREQ
1335
338
4
271
31
354
6
1
0
5
87
22
8
24
39
3
0
12
20
212
417
91
140
16
19
15
46
29
37
70
8
9
AVG ANNUAL
CRASHES/INT
% OF TOTAL
7.30
1.85
0.02
1.48
0.17
1.93
0.03
0.01
0.00
0.03
0.48
0.12
0.04
0.13
0.21
0.02
0.00
0.07
0.11
1.16
2.28
0.50
0.77
0.09
0.10
0.08
0.25
0.16
0.20
0.38
0.04
0.05
100.0%
25.3%
0.3%
20.3%
2.3%
26.5%
0.4%
0.1%
0.0%
0.4%
6.5%
1.6%
0.6%
1.8%
2.9%
0.2%
0.0%
0.9%
1.5%
15.9%
31.2%
6.8%
10.5%
1.2%
1.4%
1.1%
3.4%
2.2%
2.8%
5.2%
0.6%
0.7%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
58
2004-2006 5 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
28,491
TOT INTERSECTIONS = 986
AVERAGE
ANNUAL FREQ
3120
742
5
697
49
697
21
4
0
4
106
47
22
27
110
11
0
28
48
315
1104
276
283
28
54
72
162
126
58
197
10
8
AVG ANNUAL
CRASHES/INT
% OF TOTAL
3.16
0.75
0.01
0.71
0.05
0.71
0.02
0.00
0.00
0.00
0.11
0.05
0.02
0.03
0.11
0.01
0.00
0.03
0.05
0.32
1.12
0.28
0.29
0.03
0.05
0.07
0.16
0.13
0.06
0.20
0.01
0.01
100.0%
23.8%
0.2%
22.3%
1.6%
22.3%
0.7%
0.1%
0.0%
0.1%
3.4%
1.5%
0.7%
0.9%
3.5%
0.4%
0.0%
0.9%
1.5%
10.1%
35.4%
8.8%
9.1%
0.9%
1.7%
2.3%
5.2%
4.0%
1.9%
6.3%
0.3%
0.3%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
59
2004-2006 5 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
29,548
TOT INTERSECTIONS = 341
AVERAGE
ANNUAL FREQ
5907
1293
7
1411
96
1440
19
3
0
4
188
68
35
38
101
11
0
38
54
540
2591
363
495
61
65
109
321
309
99
343
32
22
AVG ANNUAL
CRASHES/INT
% OF TOTAL
17.32
3.79
0.02
4.14
0.28
4.22
0.06
0.01
0.00
0.01
0.55
0.20
0.10
0.11
0.30
0.03
0.00
0.11
0.16
1.58
7.60
1.06
1.45
0.18
0.19
0.32
0.94
0.91
0.29
1.01
0.09
0.06
100.0%
21.9%
0.1%
23.9%
1.6%
24.4%
0.3%
0.1%
0.0%
0.1%
3.2%
1.2%
0.6%
0.6%
1.7%
0.2%
0.0%
0.6%
0.9%
9.1%
43.9%
6.1%
8.4%
1.0%
1.1%
1.8%
5.4%
5.2%
1.7%
5.8%
0.5%
0.4%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
60
2004-2006 7 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
8,418
TOT INTERSECTIONS = 6
AVERAGE
ANNUAL FREQ
3
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
AVG ANNUAL
CRASHES/INT
0.50
0.00
0.00
0.17
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.17
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
% OF TOTAL
100.0%
0.0%
0.0%
33.3%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
33.3%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
61
2004-2006 7 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
8,418
TOT INTERSECTIONS = 4
AVERAGE
ANNUAL FREQ
16
3
0
4
1
5
0
0
0
0
3
0
0
0
1
0
0
0
0
2
3
1
3
0
0
0
0
1
1
0
0
0
AVG ANNUAL
CRASHES/INT
% OF TOTAL
4.00
0.75
0.00
1.00
0.25
1.25
0.00
0.00
0.00
0.00
0.75
0.00
0.00
0.00
0.25
0.00
0.00
0.00
0.00
0.50
0.75
0.25
0.75
0.00
0.00
0.00
0.00
0.25
0.25
0.00
0.00
0.00
100.0%
18.8%
0.0%
25.0%
6.3%
31.3%
0.0%
0.0%
0.0%
0.0%
18.8%
0.0%
0.0%
0.0%
6.3%
0.0%
0.0%
0.0%
0.0%
12.5%
18.8%
6.3%
18.8%
0.0%
0.0%
0.0%
0.0%
6.3%
6.3%
0.0%
0.0%
0.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
62
2004-2006 7 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
16,127
TOT INTERSECTIONS = 70
AVERAGE
ANNUAL FREQ
146
29
0
26
3
36
3
0
0
2
20
4
3
4
6
0
0
1
2
25
22
11
24
1
0
1
3
1
6
5
1
1
AVG ANNUAL
CRASHES/INT
% OF TOTAL
2.09
0.41
0.00
0.37
0.04
0.51
0.04
0.00
0.00
0.03
0.29
0.06
0.04
0.06
0.09
0.00
0.00
0.01
0.03
0.36
0.31
0.16
0.34
0.01
0.00
0.01
0.04
0.01
0.09
0.07
0.01
0.01
100.0%
19.9%
0.0%
17.8%
2.1%
24.7%
2.1%
0.0%
0.0%
1.4%
13.7%
2.7%
2.1%
2.7%
4.1%
0.0%
0.0%
0.7%
1.4%
17.1%
15.1%
7.5%
16.4%
0.7%
0.0%
0.7%
2.1%
0.7%
4.1%
3.4%
0.7%
0.7%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
63
2004-2006 7 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
16,931
TOT INTERSECTIONS = 38
AVERAGE
ANNUAL FREQ
251
55
0
46
4
70
1
0
0
2
28
6
1
8
6
0
0
2
3
32
60
12
37
5
3
3
5
4
12
18
1
2
AVG ANNUAL
CRASHES/INT
6.61
1.45
0.00
1.21
0.11
1.84
0.03
0.00
0.00
0.05
0.74
0.16
0.03
0.21
0.16
0.00
0.00
0.05
0.08
0.84
1.58
0.32
0.97
0.13
0.08
0.08
0.13
0.11
0.32
0.47
0.03
0.05
% OF TOTAL
100.0%
21.9%
0.0%
18.3%
1.6%
27.9%
0.4%
0.0%
0.0%
0.8%
11.2%
2.4%
0.4%
3.2%
2.4%
0.0%
0.0%
0.8%
1.2%
12.7%
23.9%
4.8%
14.7%
2.0%
1.2%
1.2%
2.0%
1.6%
4.8%
7.2%
0.4%
0.8%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
64
2004-2006 7 LANE 2 WAY UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
31,354
TOT INTERSECTIONS = 220
AVERAGE
ANNUAL FREQ
780
200
3
156
13
210
8
1
0
3
63
12
6
20
24
2
0
10
16
96
243
54
92
7
13
11
28
16
23
28
2
4
AVG ANNUAL
CRASHES/INT
% OF TOTAL
3.55
0.91
0.01
0.71
0.06
0.95
0.04
0.00
0.00
0.01
0.29
0.05
0.03
0.09
0.11
0.01
0.00
0.05
0.07
0.44
1.10
0.25
0.42
0.03
0.06
0.05
0.13
0.07
0.10
0.13
0.01
0.02
100.0%
25.6%
0.4%
20.0%
1.7%
26.9%
1.0%
0.1%
0.0%
0.4%
8.1%
1.5%
0.8%
2.6%
3.1%
0.3%
0.0%
1.3%
2.1%
12.3%
31.2%
6.9%
11.8%
0.9%
1.7%
1.4%
3.6%
2.1%
2.9%
3.6%
0.3%
0.5%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
65
2004-2006 7 LANE 2 WAY SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT =
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
33,323
TOT INTERSECTIONS = 70
AVERAGE
ANNUAL FREQ
822
212
1
202
11
213
3
0
0
1
42
9
4
9
17
1
0
5
10
89
358
43
79
10
9
7
39
28
17
35
3
3
AVG ANNUAL
CRASHES/INT
% OF TOTAL
11.74
3.03
0.01
2.89
0.16
3.04
0.04
0.00
0.00
0.01
0.60
0.13
0.06
0.13
0.24
0.01
0.00
0.07
0.14
1.27
5.11
0.61
1.13
0.14
0.13
0.10
0.56
0.40
0.24
0.50
0.04
0.04
100.0%
25.8%
0.1%
24.6%
1.3%
25.9%
0.4%
0.0%
0.0%
0.1%
5.1%
1.1%
0.5%
1.1%
2.1%
0.1%
0.0%
0.6%
1.2%
10.8%
43.6%
5.2%
9.6%
1.2%
1.1%
0.9%
4.7%
3.4%
2.1%
4.3%
0.4%
0.4%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
66
2004-2006 DIVIDED ROAD UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT = 6,890
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 136
AVERAGE
ANNUAL FREQ
100
31
1
15
5
28
1
2
0
0
7
1
0
0
18
0
0
0
1
28
15
6
9
1
2
0
1
1
2
3
0
1
AVG ANNUAL
CRASHES/INT
% OF TOTAL
0.74
0.23
0.01
0.11
0.04
0.21
0.01
0.01
0.00
0.00
0.05
0.01
0.00
0.00
0.13
0.00
0.00
0.00
0.01
0.21
0.11
0.04
0.07
0.01
0.01
0.00
0.01
0.01
0.01
0.02
0.00
0.01
100.0%
31.0%
1.0%
15.0%
5.0%
28.0%
1.0%
2.0%
0.0%
0.0%
7.0%
1.0%
0.0%
0.0%
18.0%
0.0%
0.0%
0.0%
1.0%
28.0%
15.0%
6.0%
9.0%
1.0%
2.0%
0.0%
1.0%
1.0%
2.0%
3.0%
0.0%
1.0%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
67
2004-2006 DIVIDED ROAD SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT LESS THAN 10,000 (Includes intersections with zero ADT)
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT = 7,627
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 18
AVERAGE
ANNUAL FREQ
108
30
0
23
2
33
1
0
0
0
8
3
0
0
2
0
0
0
1
24
30
7
13
1
2
1
1
3
3
4
0
5
AVG ANNUAL
CRASHES/INT
% OF TOTAL
6.00
1.67
0.00
1.28
0.11
1.83
0.06
0.00
0.00
0.00
0.44
0.17
0.00
0.00
0.11
0.00
0.00
0.00
0.06
1.33
1.67
0.39
0.72
0.06
0.11
0.06
0.06
0.17
0.17
0.22
0.00
0.28
100.0%
27.8%
0.0%
21.3%
1.9%
30.6%
0.9%
0.0%
0.0%
0.0%
7.4%
2.8%
0.0%
0.0%
1.9%
0.0%
0.0%
0.0%
0.9%
22.2%
27.8%
6.5%
12.0%
0.9%
1.9%
0.9%
0.9%
2.8%
2.8%
3.7%
0.0%
4.6%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
68
2004-2006 DIVIDED ROAD UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT = 16,090
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 293
AVERAGE
ANNUAL FREQ
523
135
2
106
20
132
8
4
0
2
27
5
0
2
46
2
0
6
5
108
151
28
49
7
22
1
8
13
10
12
3
3
AVG ANNUAL
CRASHES/INT
% OF TOTAL
1.78
0.46
0.01
0.36
0.07
0.45
0.03
0.01
0.00
0.01
0.09
0.02
0.00
0.01
0.16
0.01
0.00
0.02
0.02
0.37
0.52
0.10
0.17
0.02
0.08
0.00
0.03
0.04
0.03
0.04
0.01
0.01
100.0%
25.8%
0.4%
20.3%
3.8%
25.2%
1.5%
0.8%
0.0%
0.4%
5.2%
1.0%
0.0%
0.4%
8.8%
0.4%
0.0%
1.1%
1.0%
20.7%
28.9%
5.4%
9.4%
1.3%
4.2%
0.2%
1.5%
2.5%
1.9%
2.3%
0.6%
0.6%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
69
2004-2006 DIVIDED ROAD SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT 10,000 TO 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT = 16,427
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 75
AVERAGE
ANNUAL FREQ
490
128
1
105
14
154
5
2
0
0
26
3
2
4
21
2
0
3
5
109
165
27
45
6
7
2
10
14
7
14
3
7
AVG ANNUAL
CRASHES/INT
% OF TOTAL
6.53
1.71
0.01
1.40
0.19
2.05
0.07
0.03
0.00
0.00
0.35
0.04
0.03
0.05
0.28
0.03
0.00
0.04
0.07
1.45
2.20
0.36
0.60
0.08
0.09
0.03
0.13
0.19
0.09
0.19
0.04
0.09
100.0%
26.1%
0.2%
21.4%
2.9%
31.4%
1.0%
0.4%
0.0%
0.0%
5.3%
0.6%
0.4%
0.8%
4.3%
0.4%
0.0%
0.6%
1.0%
22.2%
33.7%
5.5%
9.2%
1.2%
1.4%
0.4%
2.0%
2.9%
1.4%
2.9%
0.6%
1.4%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
70
2004-2006 DIVIDED ROAD UNSIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT = 49,779
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 1,890
AVERAGE
ANNUAL FREQ
3796
839
9
753
93
905
34
9
0
8
164
54
14
30
215
19
0
36
14
463
1580
177
493
22
86
11
60
140
57
20
41
49
AVG ANNUAL
CRASHES/INT
% OF TOTAL
2.01
0.44
0.00
0.40
0.05
0.48
0.02
0.00
0.00
0.00
0.09
0.03
0.01
0.02
0.11
0.01
0.00
0.02
0.01
0.24
0.84
0.09
0.26
0.01
0.05
0.01
0.03
0.07
0.03
0.01
0.02
0.03
100.0%
22.1%
0.2%
19.8%
2.4%
23.8%
0.9%
0.2%
0.0%
0.2%
4.3%
1.4%
0.4%
0.8%
5.7%
0.5%
0.0%
0.9%
0.4%
12.2%
41.6%
4.7%
13.0%
0.6%
2.3%
0.3%
1.6%
3.7%
1.5%
0.5%
1.1%
1.3%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
71
2004-2006 DIVIDED ROAD SIGNALIZED INTERSECTIONS
Average Annual Crash Frequency
ADT GREATER THAN 20,000
GRAND, BAY, SOUTHWEST, UNIVERSITY AND METRO REGIONS
AVG ADT = 51,996
CRASH TYPE
TOTAL
INJURY ACC
FATAL ACC
WET
ICY
DARK
MISC SINGLE VEH
OVERTURNED
TRAIN
PRKED VEHICLE
MISC MULTI VEH
BACKING
PARKING
PEDESTRIAN
FIXED OBJ
ON ROAD OBJ
ANIMAL
BICYCLE
HEAD ON
ANGLE STRAIT
REAR-END
ANGLE TURN
SIDESWIPE SAME
REAR-END LEFT
REAR-END RIGHT
OTHER DRIVEWAY
ANGLE DRIVEWAY
REAR-END DRIVE
SIDESWIPE OPP
HEAD ON LEFT
DUAL LEFT TURN
DUAL RIGHT TURN
TOT INTERSECTIONS = 545
AVERAGE
ANNUAL FREQ
5574
1292
11
1218
102
1327
32
9
0
3
210
48
17
39
139
13
0
45
19
726
2658
191
624
30
145
23
121
249
55
36
41
101
AVG ANNUAL
CRASHES/INT
% OF TOTAL
10.23
2.37
0.02
2.23
0.19
2.43
0.06
0.02
0.00
0.01
0.39
0.09
0.03
0.07
0.26
0.02
0.00
0.08
0.03
1.33
4.88
0.35
1.14
0.06
0.27
0.04
0.22
0.46
0.10
0.07
0.08
0.19
100.0%
23.2%
0.2%
21.9%
1.8%
23.8%
0.6%
0.2%
0.0%
0.1%
3.8%
0.9%
0.3%
0.7%
2.5%
0.2%
0.0%
0.8%
0.3%
13.0%
47.7%
3.4%
11.2%
0.5%
2.6%
0.4%
2.2%
4.5%
1.0%
0.6%
0.7%
1.8%
DATA SOURCE:
Traffic Count Data (ADT)
Roadway Features
Bureau of Transportation Planning (Sufficiency)
Intersection Data (Location, Traffic Control, Influence Zone)
Traffic and Safety Division
Crash Data
Department of State Police
Analysis includes intersection related crashes only
Animal crashes excluded
72
APPENDIX D
Intersection Conflict Diagrams
4-Leg Intersection
32 Vehicle to Vehicle Conflicts
(2) T-Intersections
18 Vehicle to Vehicle
Conflicts
Divided Highway
with Directional
Cross-Overs
16 Vehicle to
Vehicle Conflicts
(2) Jughandle Intersections
18 Vehicle to Vehicle Conflicts
Split Intersection
22 Vehicle to Vehicle Conflicts
4-Leg Intersection with Quadrant
Roadway
28 Vehicle to Vehicle Conflicts
Roundabout
8 Vehicle to Vehicle Conflicts
APPENDIX E
MDOT’s Crash Reduction Factors for Various Countermeasures (January 2008)
The following crash reduction tables are for informational purposes only. Contact Safety
Programs Unit for current reduction rates.
Crash Reduction Factor for Center Left Turn Lanes
Crash Type
Crash Reduction %
Left Turn Head On
50
Left Turn Rear End
80
Non Left Turn Rear End
15
Angle
20
Other
20
Crash Reduction Factor for Right Turn Lane
Crash Type
Rear End Right Turn
Other Rear End
Sideswipe
Crash Reduction %
65
20
20
Crash Reduction Factor for Relocating Fixed Object
Crash Type
Crash Reduction %
Urban – 20
Fixed Object
Rural – 40
Crash Reduction Factor for Removing Fixed Object
Crash Type
Crash Reduction %
Fixed Object
75
Crash Reduction Factor for Increase in Lane Width (Maximum of 8 to 12 feet)
Crash Type
Crash Reduction %
Head On
5%/ft
Sideswipe
5%/ft
Parking
5%/ft
Fixed Object
5%/ft
Overturn
5%/ft
Bike
5%/ft
Crash Reduction Factor for Intersection Radii Improvements
Crash Type
Crash Reduction %
Right Turn Angle
15
Rear End
15
Sideswipe
15
Fixed Object
15
Overturn
15
Crash Reduction Factor for Directional Cross-Over Pairs
Crash Type
Crash Reduction %
Rear End Left Turn
80
Head On Left Turn
80
Angle Straight
60
Other Rear End
Increase 25
Fixed Object
Increase 20
Crash Reduction Factor for Increase to Full Width Shoulder (12 feet)
Crash Type
Crash Reduction %
Head On
15
Sideswipe
15
Parking
15
Fixed Object
15
Bike
15
Crash Reduction Factor for Increase in Bridge Width to Match Road Width
Crash Type
Crash Reduction %
Head On
40
Sideswipe
40
Fixed Object
40
Crash Reduction Factor for Correction/Improvement of Superelevation
Crash Type
Crash Reduction %
Head On
20
Fixed Object
20
Overturn
20
Sideswipe
20