ROAD SAFETY AUDIT
MAJOR HIGHWAY MEDIAN
CROSS-OVER CRASHES
I-95 ATTLEBORO/NORTH ATTLEBOROUGH
Prepared for
Prepared by
MS Transportation Systems, Inc.
Framingham, Massachusetts
June 2009
ROAD SAFETY AUDIT
MAJOR HIGHWAY MEDIAN
CROSS-OVER CRASHES
I-95 ATTLEBORO/NORTH ATTLEBOROUGH
June 2009
Prepared for
Massachusetts Highway Department
Prepared by
MS Transportation Systems, Inc.
300 Howard Street P.O. Box 967
Framingham, Massachusetts 01701
508-620-2832 508-620-6897 (fax)
www.mstransportationsystemsinc.com
TABLE OF CONTENTS
Page
INTRODUCTION
1
RSA PROCESS
3
ANALYSIS
8
SUMMARY OF RSA FINDINGS/POTENTIAL ACTIONS
12
RECOMMENDATIONS
22
APPENDIX
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I-95 Attleboro/North Attleborough Road Safety Audit
Introduction
Lane departure crashes are one of the primary fatal crash types in Massachusetts. The
Commonwealth exceeds the national average for the proportion of fatal lane departure
crashes and was designated a lead state in lane departure crashes by the American
Association of State Highway and Transportation Officials (AASHTO).
The
Massachusetts Highway Department (MassHighway) conducted a study of the problem
and found that during 2002-2004, lane departure crashes accounted for 25 percent of all
injury crashes and nearly half, 46 percent, of all fatal crashes.
As part of the effort in implementing the safety plan and specifically reducing lane
departure crashes, the MassHighway is completing a Road Safety Audit (RSA) Review
Project specifically focused on median crossing (or median cross-over) crashes on its
major highways. Road safety audits are a formal safety performance examination on
existing or future roadways by an independent audit team. These specific audits are
being conducted in locations where cross-over experience has been or has the potential
to be of concern and where the RSA team has judged that factors exist that could affect
the safety risk. During the audit, the RSA team works to identify opportunities for
enhancing safety and to recommend specific enhancements intended to reduce median
cross-over crashes and improve the overall safety along the highway.
A RSA was conducted for I-95 in Attleboro/North Attleborough as part of this project.
Figure 1 indicates the corridor section under study between Interchange No. 3 and
Interchange No. 5. This section had experienced a number of median related crashes,
including several cross-median crashes.
The purpose of this I-95 Attleboro/North Attleborough RSA is to examine potential safety
risk factors and identify opportunities to enhance safety conditions on I-95 and address
the identified factors. Recommendations contained in this report reflect the overall
consent of the RSA team and do not necessarily reflect the official views of
MassHighway.
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Page 1
95
North
Attleborough
Interchange
No. 5
Robert Toner
Boulevard
95
Interchange
No. 4
295
Attleboro
Interchange
No. 3
South Avenue
Route 1
95
N
Project Location
W
I-95 Road Safety Audit
Attleboro/North Attleborough, Massachusetts
MS Transportation Systems, Inc.
Framingham, Massachusetts
E
S
1 : 25,000
FIGURE 1
I-95 Attleboro/North Attleborough Road Safety Audit
RSA Process
The general process outlined in the guideline1 was essentially followed although with
some minor variations incorporated in the overall procedure. These were due in part to
the project location being a high speed, high volume section of an access controlled
highway. With these characteristics, there are limited areas to safely stop and gather as
a group along the section without potentially hindering traffic flow or the safety of the
RSA team. Given the team size and general character with the corridor, the team
members who visited the site prior to the team meeting did so either individually or in
smaller groups. A video recording of a drive-thru in both directions was collected by the
RSA consultant and used at the meeting to review conditions as a group. Background
material and plans were transmitted to the RSA consultant to compile and review prior to
the initial RSA team meeting. Crash and traffic volume data were transmitted to RSA
team members prior to the meeting as well. Once the initial RSA team meeting was
conducted, the RSA consultant used the input, completed the analysis and prepared a
draft document for team members to review. Data including summary crash records for
the 2004-2007 period, three (3) detailed crash descriptions of cross-over crashes, and
available record highway plans were obtained and reviewed by the RSA consultant.
Following a review of the draft, the RSA report was finalized.
•
RSA Team
The following individuals participated in of the I-95 Attleboro/North Attleborough Road
Safety Audit:
Bill Travers, MassHighway District 5, Maint.
Lisa Schletzbaum, MassHighway Safety
Timothy White, FHWA
Major Arthur McLaughlin, Troop H
Paul Nelson, EOT Planning
Trooper Daniel O’Sullivan
Paul Mission, SRPEDD
Robert Gregory, MassHighway District 5 Traffic
Bonnie Polin, MassHighway Safety
Alolade Campbell, MassHighway District 5
Adam Rerchia, SRPEDD
Shundreka Givan, FHWA
Ashish Patel, MassHighway Design
William J. Scully, MS Transportation Systems
(RSA Consultant)
•
RSA Meeting
A meeting was held on May 15, 2008 at the MassHighway District 5 Office. At the
meeting, the RSA consultant provided a brief overview of the RSA purpose, a summary
1
MS Transportation Systems, Inc., Road Safety Audits, Median Cross-Over Crashes, Audit Guidelines,
Prepared for MassHighway, October 2007.
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I-95 Attleboro/North Attleborough Road Safety Audit
of the roadway section’s characteristics and results of the review to date. The RSA
team listed above was present at the meeting. The video record of I-95 taken while
driving the corridor was viewed. During and following the video, there were further
discussions related to the possible factors related to the cross-median crashes and
possible solutions to prevent or reduce similar characteristics in the future. The RSA
team provided input on background supporting data, the key items observed in the field
and those items that were listed on the RSA Median Cross-Over Prompt List.
Key items noted at the meeting included:
 A major concern in the section is the movement of vehicles from I-95
southbound to I-295 westbound. There are vehicle queues that occur on this
ramp back onto the I-95 mainline during peak times.
 There are peak hour vehicle queues that occur on the Interchange 5 (Route
152) ramps – planning agency attempted to program major improvements but
the City was opposed. A signal is currently planned.
 Signage for Exits 4 and 5 in southbound direction can be confusing as
signage for Exit 4 occurs prior to signage for Exit 5 as a result, may not be
adequate.
 If a barrier is considered, the State Police pointed out the need for periodic
turnarounds for authorized vehicles only.
Following the RSA meeting, the RSA consultant compiled the information, for inclusion
on the analysis and in the development of recommendations.
•
Analysis Procedures
As previously indicated, the RSA analysis followed the procedure described in Guideline
with some variations and also took into consideration the methods published by the
Federal Highway Administration2 and those included in training materials3. The basic
tasks included:
•
2
3
Obtaining and reviewing crash and other traffic characteristic data and
available record plans.
Federal Highway Administration, FHWA Road Safety Audit Guidelines, Publication No. FHWA SA-06-06,
Washington, D.C., 2006.
Federal Highway Administration, Resource Center, Road Safety Audits Mini-Workshop, Jeffrey Shaw, PE,
PTOE, presented to New England ITE Section, September 19, 2006.
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I-95 Attleboro/North Attleborough Road Safety Audit
•
•
•
Conducting site reconnaissance and collecting a current record of condition
via photos and video,
identify potential hazardous issues, and
Identify and evaluate potential actions to address the noted issues.
In assessing the issues identified by the RSA Team, the relative seriousness and
potential risk relative to crash frequency and severity were determined. Using the
guidelines of FHWA4 as input and considering characteristics of this specific RSA, the
relative frequency criteria and severity criteria were identified and are presented in Table
1 and Table 2, respectively.
TABLE 1
FREQUENCY RATING
ESTIMATED
Exposure
high
medium
high
medium
low
high
Probability
high
high
medium
medium
high
low
low
medium
low
medium
low
low
EXPECTED CRASH FREQUENCY
(PER AUDIT ITEM)
5 or more crashes per year
FREQUENCY
RATING
Frequent
1 to 4 crashes per year
Occasional
Less that 1 crash per year, but
more than 1 crash every 5 years
Infrequent
Less than 1 crash every 5 years
Rare
TABLE 2
SEVERITY RATING
4
Typical Crashes Expected
(per audit item)
Expected Crash Severity
High-speed crashes; head on and
rollover crashes
Moderate-speed crashes; fixed
object or off-road crashes
Crashes involving medium to low
speeds; lane changing or
sideswipe crashes
Crashes involving low to medium
speeds; typical of rear-end or
sideswipe crashes
Probable fatality or
incapacitating injury
Moderate to severe injury
Severity
Rating
Extreme
High
Minor to moderate injury
Moderate
Property damage only or
minor injury
Low
Federal Highway Administration, Resource Center, Road Safety Audits Mini-Workshop, Jeffrey Shaw, PE,
PTOE, presented to New England ITE Section, September 19, 2006.
MS Transportation Systems, Inc.
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I-95 Attleboro/North Attleborough Road Safety Audit
Taking into consideration both frequency and severity, the relative risk of a particular
audit item was rated. The risk ratings are shown in Table 3. For each safety issue
identified, the potential seriousness of the issue as well as possible mitigation measures
have been indicated.
TABLE 3
CRASH RISK ASSESSMENT
Frequency
Rating
Low
Frequent
Occasional
Infrequent
Rare
Crash Risk Ratings:
•
C
B
A
A
Severity Rating
Moderate
High
D
C
B
A
A: minimal risk level
B: low risk level
C: moderate risk level
Extreme
E
D
C
B
F
E
D
C
D: significant risk level
E: high risk level
F: extreme risk level
RSA Field Audit
Audits were conducted by the team members prior to the RSA meeting. Key notes from
the field work are as follows:
 The inside shoulder is about 3-4 feet in width with some off-pavement
leveling area provided (another 1-3 feet +/-) depending on the specific
location.
 South of the rest (parking) area (south of I-495) where resurfacing occurred
within the past few years, rumble strips exist on the inside edge. The rumble
strip is located approximately 6 inches outside the edge line.
 A rumble strip is also in place on the outside shoulder. The outside shoulder
appears to be 10 feet in width (plans later confirmed the width).
 The median topography changes along the section. North of Route 152, it is
relatively flat or slightly depressed. South of I-295 the median generally
slopes down west to east with the southbound direction at a higher elevation
than the northbound side. There may be drainage structures in the center of
the median (plans to be checked),
 Speed limit signs indicate 65 mph with observed motorists traveling above
speed limit – possibly 5 to 10 mph above.
 There are imbedded reflectors in the pavement along lane lines but not in
edge line.
 Reflective delineators are generally not present along the median,
 The current pavement markings and surface are in generally good condition.
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I-95 Attleboro/North Attleborough Road Safety Audit
 A truck parking area exists in southbound direction about 1 mile south of I495.
 Southbound direction at the Attleboro/North Attleborough townline is on a
horizontal curve with the outside lane on the outside of the curve giving some
level of discomfort to driver. This was also noted in the northbound direction
on the curve south of the rest area.
 Evidence of numerous median entries (around 6-8) based on visual tire
tracks. Most of them were in the section north of Int. 5.
 Skid marks were also noted in certain areas – one area was prior to overpass
in the southbound direction before Interchange 4 where visibility is somewhat
constrained.
 It was also noted that relatively new tree plantings (i.e. last few years) were in
place north of Interchange 5.
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I-95 Attleboro/North Attleborough Road Safety Audit
Analysis
I-95 in Attleboro/North Attleborough is a major interstate highway that provides northsouth movement in Eastern Massachusetts connecting with Rhode Island on the south
to New Hampshire to the north. In the section under study, it consists of three (3) travels
lanes per direction. The roadway also has a full (10 foot) outside shoulder and an inside
shoulder in the range of 3 to 4 feet. Rumble strips have been installed on both the inside
and outside shoulders. The alignment is varying but can be characterized as “gentle”. It
was noted that the speed limits are posted at 65 miles per hour (mph). The median
width measured inside edge line to inside edge line is approximately 100 feet. The
unpaved portion of the median width through the section ranges from approximately 88
to 94 feet. While the length of the study section is approximately 5.7 miles, a review of
the corridor shows that the length of the “open” median in this section is approximately
2.5 miles. The topography of the median varies through the study section. South of I295 near the reservoir, the median slopes down from the SB direction to the NB
direction. North of I-295 and through Interchange No. 5 (Route 152), the median is flatter
but with a “depressed” type design. There are also areas where the median is heavily
treed that effectively blocks crossing the median in these areas. Figures 2 through 4
present photographs that depict the current conditions along the study section.
Figure 2 - I-95 Southbound approaching the Route 152 Interchange
(Interchange No. 5)
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I-95 Attleboro/North Attleborough Road Safety Audit
Figure 3 - I-95 Southbound lanes south of I-295 on-ramp.
Figure 4 - I-95 in northbound direction north of Interchange No. 3.
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I-95 Attleboro/North Attleborough Road Safety Audit
A review of available safety data was completed as part of this RSA. The review of data
included crash data for median related crashes reported for the years 2004 to 2007 and
police narratives for the cross-median events. The summary table and spot map, which
notes only the crashes that were median related, are included in the appendix. Key
aspects noted in the data included the following:
 A total of 33 median related crashes were noted during this period.
 Of the total median related crashes, 3 or 9% were cross median
crashes.
 There were no fatal crashes reported, however, approximately 50% of
the total reviewed crashes resulted in personal injuries.
 Two-thirds of the reviewed crashes occurred in the southbound
direction.
 Thirty-three percent (33%) of median related crashes occurred during
the non-light period (i.e. 9PM-5AM)
No one significant or predominant crash reason given though 12 were noted as “failure
to keep in proper lane”. In reviewing the crash reports for the section under study, driver
error and collision avoidance are more predominant than the other two reasons.
The traffic volumes observed on I-95 in this section exceed 100,000 on an average
weekday, north of I-295. Between I-295 and Interchange No. 3, the average daily
volume was observed to be 88,000. Figure 5 depicts the hourly volume by direction in
August 2007 north of Route 152. As shown, peak period flows in the peak direction
exceed 4,000 vehicles per hour. Figure 6 illustrates the variation in flow on I-95 over the
year. The data shows a consistently high volume month to month.
Figure 5 - I-95 Directional Volume August 28, 2007
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I-95 Attleboro/North Attleborough Road Safety Audit
I-95 Monthly Traffic Volume
140,000
Average Daily Volume
120,000
100,000
80,000
60,000
40,000
20,000
0
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
Month
Figure 6
I-95 Monthly Traffic Volume
North of I-295
In summary, the RSA I-95 in Attleboro/North Attleborough has identified a number of
physical and operational characteristics as being potentially a contributing factors to
increasing the risk of experiencing median related safety issues and the possibility of
median crossings although each with varied levels of seriousness. The major ones
include:
¾ Median is largely open, has a slope of 6:1 or flatter for the most part
and was considered by the RSA team as highly crossable,
¾ High volumes (>88,000 to 100,000+) on average weekday depending
on location,
¾ There is no barrier in median
¾ Queue backup onto I-95 SB from I-295.
The next section will discuss these key issues and the potential actions to consider for
addressing them.
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I-95 Attleboro/North Attleborough Road Safety Audit
Summary of RSA Findings/Potential Actions
Based on the field review, the review of crash data and discussions among the RSA
team members, the issues related to the safe operating conditions of the I-95 in the
Attleboro/North Attleborough area were identified. There were a number of factors or
issues of concern that were identified as potentially having an effect on the risk and
these are listed in Table 4 along with the assigned risk rating.
TABLE 4
SUMMARY OF FACTORS THAT POTENTIALLY AFFECT
THE RISK OF SAFETY RELATED EVENTS
Factor or Issue
Risk Rating
Significant amount of “open” median from north of
Route 152 to south of I-295 with 6:1 slopes or flatter
and considered as easily crossable
D1
Long queues in southbound direction from I-295 offramp extending several miles north
E
Sight distance constraint exists in southbound
direction north of the bridge over North Avenue
D
Significant volume increase and weaving at the I-295
interchange
D
Speed change lanes (acceleration, deceleration,
weave areas) - markings and designation are minimal
C
Adequacy motorist guidance southbound prior to
Interchange Nos. 4 and 5
B
Motorist discomfort on outside lane of curve in open
median area - northbound curve approaching rest
area
B
Motorist discomfort on outside lane of curve in open
median area - southbound curve near town line
B
Condition of non-paved area just off inside paved
shoulder – not smooth – may affect recovery
D
Condition of rumble strip and inside edge – drop-off is
significant in spots - could affect recovery
C
Southbound rest area/truck area entry - merge
B
1 A risk rating of ‘E’ would be assigned if based on total median entries.
Based on the number of cross-median crashes a risk rating of ‘D’. Given the high traffic
volume and the number of median entries, the “open” median factor could be assigned a
higher risk factor. In other words, the operational and physical characteristics of the
highway section under study is such that once a motorist makes a mistake or becomes
“errant” and enters the median, there is a high probability that the motorist will cross the
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I-95 Attleboro/North Attleborough Road Safety Audit
median and enter the opposing direction of flow although recent reported crash data
shows a small proportion of cross-median events. However, with the volumes in excess
of 100,000 vehicles per day, this type of event becomes a greater possibility.
Another significant factor noted by the RSA team concerns the I-95 southbound ramp to
I-295 westbound movement. Combination of the volume, ramp geometry and merge
design result in long vehicle queues and sluggish southbound movement that can
typically extend back on I-95 for several miles. While this condition may result in nonmedian related incidents (i.e. rear end crash types instead), it may also result in increase
lane-changing or quick, undesirable driver maneuvers that have the potential to result in
median entries. Additionally, in the I-95/I-295 interchange area, there is a substantial
increase in volumes as well as associated weaving and merging activity. Given this
characteristic together with the queuing in the southbound direction, a relatively high risk
rating was also unsigned to these factors.
One sight distance issue was identified in the southbound direction as I-95 passes over
North Avenue. While by itself, it is not a major sight distance constraint, but does
become a greater factor if long queues and slow traffic exists approaching the I-95 offramp to I-295 westbound, then the constraint becomes more pronounced. During those
times, motorists passing the overpass may come upon the queue too quickly resulting in
“quick” moves to the left or stops that may force either motorist to maneuver left in order
to avoid collision. Again, in a number of locations, once an errant motorist enters the
median, there is a good possibility that a full crossing will occur. Consequently, a
moderately high risk rating was assigned to this factor.
The speed change lanes including acceleration lanes, deceleration lanes and the weave
sections at I-295 appear to be short. In addition, guidance through the markings were
less than optimum, which may have been due in part to less than standard lengths. This
factor was assigned a risk rating of ‘C’.
Signage in the southbound direction for Exits 4 and 5 were noted to be somewhat
confusing that affects its adequacy. Specifically noted was that the Exit 4 overhead sign
(2 mile notice) is placed just prior to the overhead guide sign for Exit 5 (1 mile notice).
While noted that the confusion may contribute to some upstream lane changing if the
motorist mixed the exits up, it was determined to have a small effect on cross median
crashes. As a result, it was assigned a risk rating of ‘B’.
In the southbound direction, there was a noticeable level of driver discomfort in the high
speed (left most) travel lane on the outside of a curve – “leaning” towards median.
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I-95 Attleboro/North Attleborough Road Safety Audit
There was also a similar, smaller amount, but noticeable of driver discomfort in the
northbound direction on the curve approaching the rest area north of Interchange No. 5.
This relates to travel in the high speed travel lane. Based on further review by
MassHighway design staff who are participating on RSA team, it was determine that the
inside (high speed) travel lane may have a cross slope towards the median slightly
higher than desired. This condition in both locations contributes to the driver discomfort
and potential median entries. This factor in both locations was assigned a ‘B’.
The conditions of the rumble strip, pavement edge and surface of the off-pavement
surface were all noted as being less than desirable. While the rumble strip addresses
driver inattentiveness or driver fatigue, the edge drop off and off-pavement surface
condition affects the recovery of the errant motorists. The condition of the off-pavement
area was rated a ‘D’ and the edge drop off factor and rumble strip were assigned a ‘C’.
The last factor in the table relates to the rest/parking area in the southbound direction.
The factor noted relates specifically to the parking area exit/merge area on I-95 with
some open median in that section. Following further discussion of crash experience in
that particular area, it was assigned a risk rating of ‘B’.
Suggested actions in this program identified are intended to reduce or eliminate crossmedian crashes, injuries and fatalities related to them. In addition, the actions may
serve to reduce the severity of all the crashes. The following paragraphs include
discussion pertaining to the issues and the potential actions to consider for implement.
Given that a primary objective of this RSA was in relation to cross median crashes, the
evaluation of a median barrier was an initial action studied. The following section
describes the evaluation of the median barrier.
•
Consideration of a Median Barrier
One of the more significant actions to be considered is to install median barriers in the
current “open” areas. A barrier can be considered when there is a higher than desirable
chance or a greater risk for median cross-over crashes to occur and that have or could
result in fatalities and/or a high proportion of injury related crashes. In addition, a barrier
could be considered when the consequences or severity of a crash are worse than if the
barrier were in place.
Factors that generally come into play in deciding on whether a median should be
installed involve the following:
 High volumes and speeds
 Truck volumes and mix
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Median Width: 100 feet
ADT - 88,000-100,000
80
AVERAGE DAILY TRAFFIC
(thousands)
70
BARRIER
RECOMMENDED
60
BARRIER
CONSIDERED
50
40
BARRIER
OPTIONAL
30
20
10
0
0
10
20
30
40
MEDIAN WIDTH
(feet)
50
60
Source: AASHTO Roadside Design Guide, Chapter 6, Updated 2006
Median Barrier Warrant Evaluation
I-95 Road Safety Audit
Attleboro/North Attleborough, Massachusetts
MS Transportation Systems, Inc.
Framingham, Massachusetts
FIGURE 7
70
I-95 Attleboro/North Attleborough Road Safety Audit
 Narrow median
 History of cross-median crashes
 High risk of catastrophic event
These items have been reviewed relative to the I-95 section under study. Figure 7
presents a review of the corridor in relation to the median warrant criteria presented in
the AASHTO RDG5. As can be seen in the diagram, with the median (as measured from
edge line to edge line) is approximately 100 feet and a volume of over 100,000 vehicles
on an average day north of I-295, the intersection of the two items is in the area of the
chart where a barrier is “optional”. South of I-295, the daily volume is approximately
88,000, the criteria would still suggest “optional”.
In addition to the chart and related warrant criteria, which is a guideline, further
consideration was given to the following:
ƒ
ƒ
ƒ
ƒ
The high volume presents a likelihood of greater number of errant vehicles
entering the median,
A relatively high number of median entries (33) over the four (4) year period
and the median appears to be very crossable.
The elevation difference between the southbound and northbound directions
south of I-295 “shorten” the crossing.
There was a general discomfort felt by many RSA team members when
driving the fast (inside) lane.
Consequently, based on the analysis of the data, the field drive-thru and discussion of
the conditions by the RSA team members, it is suggested that a median barrier be
installed in the section of the route that are currently open and “crossable”. Figure 8
shows the approximate locations of the proposed new barrier location. This will
represent approximately 2.6 miles of barrier to be installed. The selection of the barrier
is discussed in the next section.
A. Barrier Selection
There are a number of barrier types that can be considered in addressing the median
cross-over crashes. These include the following:
♦
♦
♦
♦
5
Weak post W-Beam
Box Beam
Generic Low Tension Cable
High Tension Cable Barrier
♦ Strong post W-Beam
♦ Thrie Beam
♦ Concrete (Jersey)
American Association of State Highway and Transportation Officials, Roadside Design Guide,
Washington, D.C., 2002, Chapter 6 Update 2006.
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95
Location 4
4,800 ft.
Interchange
No. 5
Location 3
2,550 ft.
Interchange
No. 4
Location 2
2,250 ft.
295
Location 1
4,000 ft.
Interchange
No. 3
- approximate locations of new barrier
Note:
Total approximate barrier length is 2.6 miles
- interchanges
NOT TO SCALE
Proposed Locations for New Median Barrier
I-95 Road Safety Audit
Attleboro/North Attleborough, Massachusetts
MS Transportation Systems, Inc.
Framingham, Massachusetts
FIGURE 8
I-95 Attleboro/North Attleborough Road Safety Audit
In deciding on the type of barrier, recommended guidelines in selection are included in
Table 5 taken from the AASHTO Roadside Design Guide6.
TABLE 5
CRITERIA FOR BARRIER SELECTION
Criteria
Comments
1. Performance Capability
Barrier must be structurally able to contain and redirect
design vehicle.
Expected deflection of barrier should not exceed available
deflection distance.
Slope approaching the barrier and distance from traveled
way may preclude use of some barrier types.
2. Deflection
3. Site Conditions
4. Compatibility
5. Cost
6. Maintenance
A. Routine
B. Collision
C. Material Storage
D. Simplicity
7. Aesthetics
8. Field Experience
Barrier must be compatible with planned end anchor and
capable of transitioning to other barrier systems (such as
bridge railings).
Standard barrier systems are relatively consistent in cost,
but high-performance railings can cost significantly more.
Few systems require a significant amount of routine
maintenance.
Generally, flexible or semi-rigid systems require
significantly more maintenance after a collision than rigid
or high-performance railings.
The fewer different systems used, the fewer inventory
items/storage space required.
Simpler designs, besides costing less, are more likely to
be reconstructed properly by field personnel.
Occasionally, barrier aesthetics are an important
consideration in selection.
The performance and maintenance requirements of
existing systems should be monitored to identify problems
that could be lessened or eliminated by using a difference
barrier type.
Source: AASHTO, Roadside Design Guide, 2002, Chapter 5 Roadside Barriers.
From a cost and aesthetic perspective, the cable (flexible) barrier has its advantages
over the various guardrail systems or concrete barrier. The median slope and/or
recovery area also affects the use and placement of any barrier including guardrail.
With regard to the cable barrier, the RSA team has discussed two primary cable
alternatives noted below. In addition to the cable barrier systems, team members also
suggested that guardrail be considered in the evaluation. The alternative types of
guardrail were reviewed for potential application on this route.
6
American Association of State Highway and Transportation Officials, Roadside Design Guide,
Washington, D.C., 2002, Chapter 6 Update 2006.
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I-95 Attleboro/North Attleborough Road Safety Audit
Considerations included the volume of traffic, relative amount of truck traffic and travel
speeds. Based on these, the most applicable types of guardrail for this route include the
W-beam with strong post or the strong post thrie-beam. These rails are appropriate for
high speed highways and high volumes with a relatively high proportion of truck traffic.
Costs for each are similar. The weak post W-beam and box beam can be eliminated
due to the slope and type of highway. The concrete barrier would generally be
applicable in urban sections with limited median widths available. As a result, the
median barrier options that are valid for consideration for I-95 in this section are the
cable barrier and strong post guard rail.
Maintenance issues are also an important consideration in decisions regarding median
barrier installations. The maintenance issues that are of concern include:
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
Barrier hits per mile
Frequency of hits
Cost recovery
Cable downtime
Repair effect on traffic
Maintaining tension
Final selection of the barrier type should be based on the costs, the ability to maintain a
recovery zone, likely maintenance or repair requirements, and compatibility with future
planned widening. The key points of the cable barrier or guardrail are summarized
below.
Cable Barrier
While the low tension generic cable system has been in existence for more than 50
years, most of the recent cable system research and installation is focused on the high
tension systems. There are currently six (6) manufacturers with systems approved by
the Federal Highway Administration (FHWA) for use under certain conditions. There are
3-rope or 4-rope cable systems as shown in the following two photographs.
This barrier type can be installed on slopes of 6:1 or flatter with little constraint on
placement. There are certain systems (i.e. Brifen and Gibraltor 4 rope) that have been
approved for slopes as steep as 4:1. In addition to the lower installation costs, the cable
barrier can usually be located sufficiently away from the pavement area to allow for
recovery zone and a minimal number of hits.
MS Transportation Systems, Inc.
Page 19
I-95 Attleboro/North Attleborough Road Safety Audit
3 Cable CASS System on Route 213
4 – Rope Brifen System on I-495
Guardrail
In general, guardrail could be placed toward or in the center of the median where slopes
are 10:1 or flatter (i.e. I-93 Braintree) as well as at the edge of a steep slope or where
minimal recovery zones exist. With the guardrail placed within several feet of the
pavement edge, a clear zone (or recovery area) would be eliminated at least on one side
of the median if guardrail is applied on only one side of the median.
Per mile costs of the basic types of median barrier treatment to be considered for this
route are summarized in Table 6. Shown in the table are estimated per mile costs of
installing a cable barrier, a double faced W-beam guardrail and a double faced thriebeam guardrail. As can be seen, the cable barrier is expected to be the lower cost
option. It should be noted that the estimated costs for the cable barrier are largely based
on recent limited applications in the Commonwealth. Construction costs for cable
installation could be substantially lower based on experience in other parts of the country
(examples in Appendix). The W-beam rail is a lower cost option compared to the thriebeam, however, there is slightly greater deflection with the W-beam.
TABLE 6
COMPARISON PER MILE COSTS
Cable vs. Guardrail
Costs/Mile
Cable
$144,000
W-beam
$171,000
Thrie beam
$213,000
MS Transportation Systems, Inc.
Page 20
I-95 Attleboro/North Attleborough Road Safety Audit
Based on the above costs, the installation of cable barrier in the identified sections is
estimated to cost approximately $374,400 while use of thrie-beam would result in a cost
of approximately $553,800. The next section outlines all of the RSA team
recommendations including the median barrier.
MS Transportation Systems, Inc.
Page 21
I-95 Attleboro/North Attleborough Road Safety Audit
Recommendations
As a result of the RSA analysis and team input, a set of recommendations have been
identified and are summarized in Table 7. It was the overall consensus of the I-95
Attleboro/North Attleborough RSA team that due to the high volumes of traffic, the traffic
characteristics in the area of Interchange 4 and between Interchange Nos. 4 and 5 in the
southbound direction that can influence lane changing behavior, a series of suggestions
were appropriate in order to reduce the risk of median entry and cross median crashes
in the study sections. These actions are intended to eliminate the chance of crossmedian crashes as well as reduce the severity of all crashes and improve the overall
safety condition of this section of I-95 in Attleboro/North Attleborough.
Identified in the table in addition to the risk factor and recommended action are the
estimated costs and potential timeframe (i.e. short (0-1 year), medium (1-3 years) and
long (>3 years).
A major action suggested is the installation of a median barrier in several “open”
sections. For several reasons including costs, maintaining a recovery area and
aesthetics, it is recommended that a cable barrier be installed. Figure 8 previously
illustrated the approximate locations of the new installation that totals about 2.6 miles in
4 different sections. Construction decisions can be made during design relative to
retaining the existing small groves of trees or the recently planted trees in the northern
area of the study section. Based on a unit cost of $144,000 per mile, installing the cable
barrier is estimated at $374,400.
Another major area of improvement suggested by the RSA team relates to the guidance
and traffic design of the I-295 (Interchange No. 4) interchange with I-95. In an effort to
reduce the peak period vehicle queuing back onto I-95, a new striping plan for the
southbound section from the I-95 northbound on-ramp is suggested to “smooth” the I295 merging. It is also recommended that better advance warning “caution” signs be
installed approaching the I-295 interchange in both directions. Figure 9 illustrates in
concept the proposed marking plan while Figure 10 illustrates potential sign legends.
Figure 11 provides information relative to the placement of the signs. The location of
SIGN C would be two miles prior to Exit 4 (I-295) while SIGN B would be located at
Station 395+00 (Plan Reference Attleboro-Canton I-95 Project #601166).
Also in the southbound direction, it is recommended that a queue detection system be
put in place on the I-95 southbound on-ramp to I-295 with variable message sign (VMS)
placed at approximately the North Avenue overpass. While this may be a longer tern
option, this is intended to address the visibility constraint if long ramp queues and slow
morning southbound traffic exists south of the overpass.
MS Transportation Systems, Inc.
Page 22
I-95 Attleboro/North Attleborough Road Safety Audit
TABLE 7
SUMMARY OF RECOMMENDATIONS
Risk Factor
Significant amount of “open”
median from north of Route 152
to south of I-295 with 6:1 slopes
or flatter and considered as easily
crossable
Long queues in southbound
direction from I-295 off-ramp
extending several miles north
Risk
Rating
D1
E
ƒ
Recommended
Action
Install cable barrier
ƒ Modify pavement
markings to indicate single
lane on I-295 from I-95 NB
on-ramp
ƒ Widen I-295 SB on ramp
to 2 lanes
ƒ Install warning signage in
SB direction north of I-295
Estimated Cost
Estimated
Timeframe
ƒ medium
term
(order of magnitude)
$374,400
$5,000
ƒ short term
TBD
ƒ long term
$20,000
ƒ short term
ƒ Install static warning sign
ƒ Install electronic queue
detector – VMS warning
sign in SB direction
$10,000
ƒ short term
TBD
ƒ long term
$10,000
TBD
ƒ short term
ƒ short term
TBD
(est. low cost)
ƒ short term
Sight distance constraint exists in
southbound direction north of the
bridge over North Avenue
D
Significant volume increase and
weaving at the I-295 interchange
D
ƒ Add safety warning signs
ƒ Increase enforcement
Speed change lanes
(acceleration, deceleration,
weave areas) - markings and
designation are minimal
C
ƒ improve markings
Adequate motorist guidance
southbound prior to Interchange
Nos. 4 and 5
B
ƒ combine 1st sign for Exits
5 and 4
$20,000
ƒ short term
Motorist discomfort on outside
lane of curve in open median
area - northbound curve
approaching rest area
B
ƒ Improve delineation with
posts, signage or markers
ƒ Check superelevation
ƒ Adjust during resurfacing
$3,000
ƒ short term
-
ƒ short term
ƒ medium to
long term
Motorist discomfort on outside
lane of curve in open median
area - southbound curve near
townline
B
ƒ Improve delineation with
posts, signage or markers
ƒ Check superelevation
ƒ Adjust during resurfacing
-
ƒ short term
Condition of non-paved area just
off inside paved shoulder – not
smooth – may affect recovery
D
ƒ Provide more fill and
regrade
TBD
(anticipate low cost)
ƒ short term
Condition of rumble strip and
inside edge – drop-off is
significant in spots – could affect
recovery
C
ƒ Consider installing the
angled safety edge
Estimated at 1 to 2
percent of total
resurfacing
ƒ long term
as part of
resurfacing
Southbound rest area/truck area
entry – merge
B
ƒ Improve signage for
merge and Yield control
$2,000
ƒ Short term
ƒ short term
ƒ medium to
long term
1 A risk rating of ’E’ would be assigned if based on total median entries
MS Transportation Systems, Inc.
Page 23
MERGING
TRAFFIC
1100 FEET
SIGN A
EXPECT OFF-RAMP
BACKUPS AT
EXIT 4
EXPECT STOPPED
TRAFFIC
NEXT 2 MILES
SIGN C
SIGN B
CONCEPTUAL ONLY NOT TO SCALE
Potential Sign Legends
I-95 Road Safety Audit
Attleborough, Massachusetts
MS Transportation Systems, Inc.
Framingham, Massachusetts
Figure 10
95
c
5
B
4
295
A
3
3
LEGEND
A
- (see Figure 8) - place northbound approx. Sta. 329+90
B
- (see Figure 8) - place southbound approx. Sta. 395+00
c
- (see Figure 8) - place southbound approx. Sta. 62+00
- interchanges
NOT TO SCALE
Potential Major Sign Placement
I-95 Road Safety Audit
Attleborough, Massachusetts
MS Transportation Systems, Inc.
Framingham, Massachusetts
FIGURE 11
I-95 Attleboro/North Attleborough Road Safety Audit
Pavement markings at the interchanges could be improved. The use of dotted extension
lines enhance motorist guidance. The current MUTCD depicts dotted lines as an option
for deceleration lanes and weave sections between on- and off-ramps. The 2009
updated MUTCD is anticipated to include dotted extension lines for acceleration lanes as
well. Examples of the markings are included in the Appendix.
Addressing the driver discomfort issue and cross-slope of the inside travel lane in the
noted southbound and northbound directions will require adjustments in future
resurfacing projects following additional engineering analysis. Resurfacing will likely be
medium to long term projects. Short term actions would include new delineator posts
along the median and/or warning (guidance) signs. A short term action would also be to
check the cross slope (superelevation).
Other safety actions suggested for I-95 include using the flexible delineator posts along
the inside edge of the highway, regrading portions of the unpaved median including
addressing the edge drop off where its significant, improved warning and control signs at
the southbound rest area and increase the level of enforcement of speeds and
inappropriate lane changing behavior.
MS Transportation Systems, Inc.
Page 27
I-95 Attleboro/North Attleborough Road Safety Audit
Appendix
•
•
•
•
•
•
MS Transportation Systems, Inc.
RSA Meeting Agenda
RSA Attendees List
Median Crash Diagram
Crash Data
Traffic Volume Data
Samples of Lane Markings
Page 28
Road Safety Audit
N. Attleborough/Attleboro – Interstate 95
Meeting Location: MassHighway District 5 Office
1000 County Street, Taunton
Thursday, May 15, 2008
10:00 AM – 12:00 PM
Type of meeting:
Cross Median – Road Safety Audit
Attendees:
Invited Participants to Comprise a Multidisciplinary Team
Please bring:
Thoughts and Enthusiasm!!
10:00 AM
Welcome and Introductions
10:15 AM
Introduction to Road Safety Audits and Cross Median Crashes
10:30 AM
Review of Site Specific Material
• Crash & Volume Summaries– provided in advance
• Existing Geometries and Conditions
• Video and Images
11:00 AM
Completion of RSA
• Identification of Safety Concerns – using RSA Prompt List as a guide
• Identification of Possible Countermeasures
12:00 PM
Adjourn for the Day – but the RSA has not ended
Instructions for Participants:
• Before attending the RSA on May 15th participants are encouraged to drive
Interstate 95 in N. Attleborough and Attleboro (Interchanges 3-6) and
complete/consider elements on the RSA Prompt List with a focus on safety factors
affecting cross median crashes.
• All participants will be actively involved in the process throughout. Participants
are encouraged to come with thoughts and ideas, but are reminded that the
synergy that develops and respect for others’ opinions are key elements to the
success of the overall RSA process.
• After the initial RSA meeting, participants will be asked to comment and respond
to the document materials to assure it is reflective of the RSA completed by the
multidisciplinary team.
ROAD SAFETY AUDIT MEETING
I-95 - Mya 15, 2008
MassHighway District 5 Offices, Attleboro/North Attleborough MA
Attendance List
Name
Agency/Dept.
Email
William Scully
MS Transportation Systems
bscullyjr@mac.com
William Travers
MHD District 5 Maint.
Bill.Travers@mhd.state.ma.us
Timothy White
FHWA
Timothy.A.White@fhwa.dot.gov
Paul Nelson
EOTP
Paul Mission
SRPEDD
pmission@srpedd.org
Bonnie Polin
MHD Safety
Bonnie.Polin@state.ma.us
Adam Rerchia
SRPEDD
arerchia@srpedd.org
Ashish Patel
MHD Design
ashish.patel@mhd.state.ma.us
Lisa Schletzbaum
MHD Safety
lisa.schletzbaum@mhd.state.ma.us
Major Arthur McLaughlin
Troop H
Trooper Daniel O'Sullivan
Troop H
daniel.osullivan@pol.state.ma.us
Robert Gregory
MHD District 5 Traffic
robert.gregory@mhd.state.ma.us
Alolade Campbell
MHD District 5
Alolade.Campbell@mhd.state.ma.us
Shundreka Givan
FHWA
Shundreka.Givan@fhwa.dot.gov
MS Transportation Systems, Inc.
±
I-95 Interchange Median Crashes
VA R
D
UE
U LE
N
AV E
DR Y
LAN
LLY
BO
1
§
¦
¨
NC
IS
KE
LANDRY AVENUE
I
SM
FR A
95
TH
RE
ST
NORTH
ATTLEBOROUGH
ET
Crash IDs
between 5-13
2
ST
JOHN L DIET
EL
M
3
4
RE
ET
AR D
SCH BO ULEV
"
)5
Crash IDs
between 14-29
R
NO
TH
UE
EN
AV
£
¤
152
30
MOUN T HOPE
STRE ET
ST REET
NORTH MA IN
31
ATTLEBORO
"
)4
32
§
¦
¨
295
HOLD
E
Legend
Type of Median Crash 2004-2007 *
N S TR
EET
Major Roads
Cross Median, Non-Fatal Crash
Interstate
Median, Fatal Crash
Principal Arterial
Median, Non-Fatal Crash
Minor Arterial
Municipal Boundary
Collector
Local
S
WE
T
TS
E
RE
T
* 2007 crash file has not yet been closed.
0
0.2
0.4
0.6
0.8
Miles
MASSACHUSETTS HIGHWAY SAFETY DIVISION
CRASH SUMMARY
I-95
ROADWAY:
NO.
CITY:
1/1/2004
STUDY PERIOD:
CRASH NUMBER
TO
12/31/2007
TRAVEL
LIGHT
WEATHER
ROAD
REASON FOR
LANES
CONDITION
CONDITION
SURFACE
RUNNING OFF ROAD LEFT
ATTLEBORO AND NORTH ATTLEBOROUGH
LOCATION:
BETWEEN EXITS #4 AND #6
VEHICLE
MEDIAN OR CROSS
DRIVER CONTRIBUTING
CRASH
MOVEMENT
MEDIAN CRASHES
CAUSE
SEVERITY
1
2046535
NB
Dark - Not Lighted
Clear
Dry
Lost control of vehicle and overturned
Travel Lane to Trees in the Median
Median
Failure to keep in proper lane
2
1931024
NB
Dark - Not Lighted
Clear
Dry
Vehicle struck another parked vehicle in the breakdown lane
Travel Lane to Median
Median
Inattention
Non-Fatal Injury
3
1881627
SB
Dark - Not Lighted
Clear
Dry
Vehicle strike another vehicle in the rear, spun out and overturned
Travel Lane to Median
Median
Exceeded Speed Limit and Alcohol
Non-Fatal Injury
4
1881747
SB
Daylight
Clear
Dry
Vehicle right rear tire blew out and overturned
Travel Lane to Median
Median
No Improper Driving
Property Damage Only
5
1758154
SB
Daylight
Clear
Dry
Lost control of vehicle and traveled off the road
Travel Lane to Trees in the Median
Median
Failure to keep in proper lane
Property Damage Only
6
1900739
SB
Dark - Not Lighted
Clear
Dry
Lost control of vehicle and overturned
Travel Lane to Median
Median
Failure to keep in proper lane
Non-Fatal Injury
7
1904197
SB
Dark - Not Lighted
Clear
Dry
Vehicle changed lanes to an already occupied lane and strike the side of another vehicle
Travel Lane to Trees in the Median
Median
Failure to keep in proper lane
Property Damage Only
8
1930524
SB
Daylight
Clear
Dry
Vehicles distracted due to box truck stuck in the median
Travel Lane to Median
Median
Distracted
Property Damage Only
9
1954971
SB
Daylight
Clear
Dry
Vehicle load shifted and caused vehicle to overturn
Travel Lane to Median
Median
No Improper Driving
Non-Fatal Injury
10
1986779
SB
Dark - Not Lighted
Cloudy
Dry
Lost control of vehicle and struck guardrail
Travel Lane to Median Guardrail to Middle Median
Median
Failure to keep in proper lane
Non-Fatal Injury
Non-Fatal Injury
Non-Fatal Injury
11
2046325
SB
Daylight
Clear
Dry
Lost control of vehicle and swerved off the road
S/B Travel Lanes to N/B Travel Lanes
Cross Median
Swerving in roadway
12
2046719
SB
Daylight
Rain
Dry
Vehicle changed lanes to an already occupied lane and strike the left side of another vehicle
Travel Lane to Median
Median
Failure to keep in proper lane
Property Damage Only
13
2156432
SB
Daylight
Cloudy
Dry
Vehicle changed lanes to an already occupied lane and overcorrected
S/B Travel Lanes to N/B Travel Lanes
Cross Median
Over-correcting/Over-steering
Property Damage Only
14
1758241
SB
Dark - Not Lighted
Clear
Dry
Fallen asleep and vehicle drifted into median and overturned
Travel Lane to Median
Median
Fatigued/Asleep
Property Damage Only
15
1809506
NB
Daylight
Clear
Dry
Vehicle intentionally forced another vehicle into the guardrail
Travel Lane to Median Guardrail
Median
Operating vehicle in reckless manner
Non-Fatal Injury
16
1930255
NB
Dark - Not Lighted
Clear
Dry
Vehicle was cut-off by unknown vehicle
Travel Lane to Median Jersey Barrier
Median
Swerving or avoiding due to vehicle in roadway Property Damage Only
17
1930373
NB
Dark - Not Lighted
Clear
Dry
Vehicle was cut-off by unknown vehicle
Travel Lane to Median Barrier
Median
Swerving or avoiding due to vehicle in roadway Property Damage Only
18
2046329
NB
Dark - Not Lighted
Clear
Dry
Vehicle rear ended another vehicle and traveled off to the median
Travel Lane to Median
Median
Followed too closely
Non-Fatal Injury
19
2114175
NB
Dark - Not Lighted
Clear
Dry
Vehicle hit another vehicle in right rear, lost control and struck the guardrail
Travel Lane to Median Guardrail
Median
Alcohol
Property Damage Only
20
2148916
NB
Daylight
Rain
Wet
Vehicle rear ended another vehicle and struck the guardrail
Travel Lane to Median Guardrail to Travel Lane
Median
Failure to keep in proper lane
Non-Fatal Injury
21
2167722
NB
Daylight
Snow
Ice
Lost control of vehicle in snow storm and bounced off guardrail hitting other vehicles
Travel Lane to Median Guardrail to Travel Lane
Median
Swerving due to slippery surface in roadway
Non-Fatal Injury
22
2205414
NB
Daylight
Sleet, Hail, Freezing Rain Slush
Lost control of vehicle in snowy condition , struck guardrail and spun around hitting other vehicles
Travel Lane to Median Guardrail to Travel Lane
Median
Driving too fast for condition
Non-Fatal Injury
23
1930583
SB
Daylight
Clear
Lost control of vehicle and hit concrete bridge support pillars
Travel Lane to Median Bridge Support Pillars
Median
Failure to keep in proper lane
Property Damage Only
Wet
24
2046496
SB
Daylight
Clear
Dry
Vehicle rear ended another vehicle and traveled off to the median
Travel Lane to Median
Median
Followed too closely
Non-Fatal Injury
25
2122601
SB
Daylight
Clear
Dry
Vehicle swerved into travel lane and hit another vehicle
Travel Lane to Median
Median
Failure to keep in proper lane
Property Damage Only
26
2216274
SB
Daylight
Clear
Dry
Vehicle steering locked up and caused vehicle to overturned
Travel Lane to Median
Median
Operating defective equipment
Property Damage Only
27
2216861
SB
Daylight
Clear
Dry
Vehicle rear tire blew out and overturned
Travel Lane to Median
Median
No Improper Driving
Non-Fatal Injury
28
2224615
SB
Daylight
Not Reported
Dry
Vehicle changed lanes to an already occupied lane and strike the side of another vehicle
Travel Lane to Trees in the Median
Median
Failure to keep in proper lane
Property Damage Only
29
2265154
SB
Daylight
Clear
Dry
Vehicle changed lanes to an already occupied lane and strike the left side of another vehicle
Travel Lane to Median Guardrail
Median
Failure to keep in proper lane
Non-Fatal Injury
30
1874284
SB
Daylight
Clear
Dry
Vehicle was cut-off by unknown vehicle and overturned
Travel Lane to Median
Median
Operating vehicle in reckless manner
Property Damage Only
31
1855212
NB
Daylight
Cloudy
Dry
Vehicle changed lanes to an already occupied lane and caused another vehicle to strike guardrail
Travel Lane to Right Guardrail to Median
Median
Swerving or avoiding due to vehicle in roadway Not Reported
32
2265426
SB
Daylight
Clear
Dry
Vehicle rear ended another vehicle and traveled off to the median
S/B Travel Lanes to N/B Right Guardrail
Cross Median
Exceeded Speed Limit
Non-Fatal Injury
33
1968049
NB
Daylight
Clear
Dry
Vehicle swerved into travel lane and hit other vehicle
Travel Lane to Right Guardrail to Median Guardrail to Travel Lane
Median
Failure to keep in proper lane
Property Damage Only
LIGHT CONDITION
WEATHER CONDITION
TOTAL NO.
DAYLIGHT
DARK-NOT LIGHTED
CLEAR
CLOUDY
RAIN
SNOW
SLEET, HAIL, FREEZING RAIN
33
22
11
25
3
2
1
1
1
100%
67%
33%
76%
9%
6%
3%
3%
3%
NON-FATAL INJURY
NOT REPORTED
ROAD SURFACE
DRY
WET
CRASH SEVERITY
MEDIAN OR CROSS MEDIAN
ICE
SLUSH
MEDIAN
CROSS MEDIAN
NOT REPORTED
PROPERTY DAMAGE ONLY
29
2
1
1
30
3
16
16
1
88%
6%
3%
3%
91%
9%
48%
48%
3%
FAILURE TO KEEP IN PROPER LANE
SWERVING OR AVOIDING DUE TO VEHICLE IN ROADWAY
DRIVER CONTRIBUTING CAUSE
NO IMPROPER
EXCEEDED SPEED
EXCEEDED SPEED
DRIVING
LIMIT
LIMIT & ALCOHOL
3
1
1
9%
3%
3%
SWERVING DUE TO SLIPPERY
OPERATING VEHICLE
OVER-CORRECTING/
SURFACE IN ROADWAY
IN RECKLESS MANNER
OVER-STEERING
DRIVING TOO FAST
FOLLOWED TOO
FOR CONDITION
CLOSELY
1
1
2
12
3
1
3%
3%
6%
36%
9%
3%
ALCOHOL
ROADWAY
DRIVER CONTRIBUTING CAUSE
INATTENTION
DISTRACTED
FATIGUED/
OPERATING DEFECTIVE EQUIPMENT
ASLEEP
1
2
1
1
1
1
1
3%
6%
3%
3%
3%
3%
3%
2007 CRASH INFORMATION ARE NOT COMPLETE
CRASH SUMMARY IS BASED ON CRASH REPORTS WITH STATE POLICE NARRATIVES
SWERVING IN
Directional Traffic Volumes along I-95, North of Rte. 152, North
Attleboro
Tuesday, August, 28, 2007
Northbound Direction
6,000
5,000
4,000
3,000
2,000
1,000
AM
10
:0
0
AM
12
:0
0
PM
2:
00
PM
4:
00
PM
6:
00
PM
8:
00
PM
10
:0
0
PM
AM
8:
00
AM
6:
00
AM
4:
00
2:
00
AM
0
12
:0
0
Hourly Volume (Number of Vehicles)
Southbound Direction
Time of Day
I-95, North of RTE. 152 (Interchange 5) 08/28/2007
Northbound Southbound
Start time
Direction
Direction
TOTAL
12:00 AM
512
700
1,212
1:00 AM
402
393
795
2:00 AM
356
342
698
3:00 AM
438
261
699
4:00 AM
937
364
1,301
5:00 AM
2,627
836
3,463
6:00 AM
4,579
1,979
6,558
7:00 AM
5,167
3,055
8,222
8:00 AM
4,183
3,240
7,423
9:00 AM
3,098
2,770
5,868
10:00 AM
2,727
2,663
5,390
11:00 AM
2,630
2,453
5,083
12:00 PM
2,566
2,568
5,134
1:00 PM
2,684
2,561
5,245
2:00 PM
2,975
2,929
5,904
3:00 PM
2,988
3,710
6,698
4:00 PM
3,257
4,143
7,400
5:00 PM
3,413
4,482
7,895
6:00 PM
2,697
3,529
6,226
7:00 PM
1,899
2,450
4,349
8:00 PM
1,645
1,892
3,537
9:00 PM
1,387
1,544
2,931
10:00 PM
1,055
1,205
2,260
11:00 PM
702
995
1,697
Daily Total
54,924
51,064
105,988
a-Parallel
deceleration lane
b-Tapered
deceleration lane
Neutral area
Optional
chevron
markings
Channelizing
lines
Theoretical gore
point
Channelizing
lines
Broken lane
markings for
one-half of
full-width
deceleration
lane
Optional
dotted
extension
of lane
line
Legend
Direction of
travel
Source: MUTCD
Potential Pavement Markings Off-Ramp Deceleration Lanes
NOT TO SCALE
MS Transportation Systems, Inc.
Framingham, Massachusetts
Neutral area
Optional chevron
markings
Theoretical gore
point
Broken or dotted lane line
markings for full length of
acceleration/deceleration lane
Channelizing
lines
Legend
Direction of
travel
Source: MUTCD
Example of Channelizing Line Applications
for Entrance-Exit (Weave) Ramp Markings
NOT TO SCALE
MS Transportation Systems, Inc.
Framingham, Massachusetts