ROAD SAFETY AUDIT
MAJOR HIGHWAY MEDIAN
CROSS-OVER CRASHES
I-495 MIDDLEBOROUGH
Prepared for
Massachusetts Highway Department
Prepared by
MS Transportation Systems, Inc.
Framingham, Massachusetts
March 2009
ROAD SAFETY AUDIT
MAJOR HIGHWAY MEDIAN
CROSS-OVER CRASHES
I-495 MIDDLEBOROUGH
FINAL REPORT
March 2009
Prepared for
Massachusetts Highway Department
Prepared by
MS Transportation Systems, Inc.
Consulting Engineers and Planners
300 Howard Street, P.O. Box 967
Framingham, Massachusetts 01701
Tel: (508) 620-2832 Fax: (508) 620-6897
www.mstransportationsystemsinc.com
I-495 Middleborough Road Safety Audit
TABLE OF CONTENTS
Page
INTRODUCTION
1
RSA PROCESS
3
ANALYSIS
8
SUMMARY OF RSA FINDINGS/POTENTIAL ACTIONS
12
RECOMMENDATIONS
19
APPENDIX
24
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INTRODUCTION
Lane departure crashes are one of the primary fatal crash types in Massachusetts. The
Commonwealth exceeds the national average for 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 (MHD) 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.
An RSA was conducted for the I-495 in Middleborough as part of this overall effort. The
roadway section under study, shown in Figure 1, was essentially between Interchange
No. 6 and a point approximately 1.5 miles south of Interchange No. 3. This section had
experienced a number of median related crashes that included several reported crossover incidents. In November 2006, a quick action project consisting of installing a 4-rope
Brifen cable median barrier system on a portion of the road section in the vicinity of
Interchange No. 3 in each direction for a total length of approximately 4,500 feet.
The purpose of this I-495 Middleborough RSA was to review current safety
characteristics on the highway section under study, identify potential risk factors and to
recommend a set of actions to enhance the safe operation of the highway section under
study.
Recommendations contained in this report reflect the overall consent of the RSA team
but do not necessarily reflect the official opinions or views of MassHighway.
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Middleborough
Bedford Street
44
495
Interchange
6
44
Interchange
5
28
Interchange
4
18
105
79
Interchange
3
495
Route 28
N
Project Location
W
S
I-495 Road Safety Audit
Middleborough, Massachusetts
MS Transportation Systems, Inc.
E
1 : 25,000
Framingham, Massachusetts
FIGURE 1
I-495 Middleborough Road Safety Audit
RSA PROCESS
In conducting the RSA, the overall procedures outlined in the Median Cross-Over RSA
Guideline Report1 with some modifications given the characteristics of the facility being
reviewed. The process included identifying RSA team members; conducting field visits;
holding a RSA team meeting and then completing an assessment of the data and
findings from the field visits and meetings to render recommended actions for
MassHighway to consider. Data including recent traffic volume data, summary crash
records for the 2004-2007 period, detailed crash reports of cross-over crashes, and
available record highway plans were obtained and reviewed by the RSA consultant. In
addition, maintenance records related to the cable barrier since late 2006 were provided
by the Department. Field visits were conducted by the RSA team members. A video
recording of the sections under study was taken by the RSA Consultant. The site visits
were completed prior to the RSA team meeting that was held on April 18, 2008 at the
MassHighway District 5 offices. At that meeting, the RSA consultant provided a brief
overview of the RSA purpose, a summary of the roadway section’s characteristics and
results of the review to date. The RSA team provided input and discussed the key items
noted in the field and that were listed on the RSA Median Cross-Over Prompt List.
Issues and concerns were noted. Following the RSA meeting, the RSA consultant
compiled the information, completed the analysis and circulated the draft report.
•
RSA Team
The following were members of the I-495 Middleborough Road Safety Audit:
Donald Pettey, MassHighway District 5
Neil Boudreau, State Traffic Engineer
Daniel Mulkern, State Police Troop D
Thomas Broderick, MHD Deputy Chief
Engineer for Safety & Mobility
Hardy Patel, MassHighway Highway Design
•
Timothy Kochan, MassHighway District 5
Robert Gregory, MassHighway District Traffic
Alolade Campbell, MassHighway District 5
James Hadfield, SRPEDD
Lisa Schletzbaum, MassHighway Boston
William J. Scully, MS Transportation Systems
(RSA Consultant)
RSA Team Meeting
The RSA team meeting took place on April 18, 2008 at the District 5 offices in Taunton.
The team included engineers, planners and a representative from the State Police
barrack that has jurisdiction of I-495 in Middleborough providing a range of perspectives
1
MS Transportation Systems, Inc., Road Safety Audits, Median Cross-Over Crashes, Audit Guidelines, Prepared for
MassHighway, October 2007.
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and expertise. A list of the team members at the meeting with contact information is
included in the Appendix. As stated previously, overall characteristics and conditions of
the study section were presented. A video and still photographs were reviewed by the
RSA team and a discussion of the potential safety opportunities for enhancement
followed. The key items resulting from that meeting included the following:
 The median is narrow, relatively level and very crossable.
 The overall alignment of the roadway is fairly straight and level with a few
exceptions.
 Volumes in the corridor and its surrounding area are projected to increase
significantly and with that, added concern for safety along this particular
roadway.
There were other items also raised by RSA members at the meeting. Included were that
the acceleration-deceleration lanes were perceived to be shorter than desirable. Also,
there are periodically long ramp queues during peak hours, predominantly noted as
occurring at the Route 44 (Exit 6) northbound exit ramp. While queues have not been
regularly observed to reach the mainline, motorists exiting the highway cannot see long
queues on the ramp due to the geometry and vegetation.
Staff from the RPA had noted that it appeared the section (or a portion of it) was
designated as a “low salt” zone but signs were missing. This was later checked and it
was verified that the entire study section is a “low salt use” zone. Lastly, a comment was
made as to the corridor section perceived as especially dark and that lighting, possibly
focused at the interchanges, could be considered in the evaluation.
It was also noted at the meeting that a roadway rehabilitation project was just beginning
along the entire section under study. The rehabilitation project is to include a minor
widening of the inside shoulder to accommodate a rumble strip, embedded reflective
markers along the travel lane line, adjustments to drainage and resurfacing. The project
is expected to be completed later in 2009 or early 2010.
•
Analysis Procedures
As previously indicated, the RSA analysis generally followed the procedure described in
the previously referenced Guideline with some variations and also took into
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consideration the methods published by the Federal Highway Administration2 and those
included in training materials3. The basic tasks included:
•
Obtaining and reviewing crash and other traffic characteristic data and
available record plans.
•
Conducting site reconnaissance and collecting a current record of condition
via photos and video,
•
Identifying opportunities for enhancement, and
•
Identifying and evaluating 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 FHWA 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
Source: FHWA RSA Training Workshop
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.
2
3
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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TABLE 2
SEVERITY RATING
Typical Crashes Expected
(per audit item)
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
Expected Crash Severity
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
Source: FHWA RSA Training Workshop
TABLE 3
CRASH RISK ASSESSMENT
Frequency
Rating
Frequent
Occasional
Infrequent
Rare
Severity Rating
Low
Moderate
High
Extreme
C
B
A
A
D
C
B
A
E
D
C
B
F
E
D
C
Source: FHWA RSA Training Workshop
Crash Risk Ratings:
A: minimal risk level
B: low risk level
C: moderate risk level
•
D: significant risk level
E: high risk level
F: extreme risk level
RSA Field Audit
Field audits were conducted by the RSA team members between on or before April 18,
2008. In general, the field visits included “drive-throughs” in each direction of the study
section noting physical conditions and the “feel” of the driver. The Prompt List
developed as part of the RSA process was used as a guide. The prompt list is included
in the appendix for background. The field audits showed the following:
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There are two travel lanes per direction in the section under study.
For the most part, the highway consists of long straight segments with a
relatively level vertical alignment except for overpasses such as at
Interchange No. 4 (Route 105).
The southern end of the study section in the vicinity of Interchange No. 3
has cable barrier (4 rope) installed approximately 8 to 10 feet from the
northbound pavement edge.
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I-495 Middleborough Road Safety Audit
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Except for the one existing run of cable median barrier, the median is
open, slightly depressed. It appears relatively narrow – 50 feet or less.
Parking areas (“stay awake”) are located in each direction south of
Interchange No. 4; two small ones exist on the southbound side within
close proximity of each other resulting in multiple diverge-merge points.
The inside shoulder is narrow (i.e. 1-2 feet in width).
Rumble strips do not exist (expected to be installed during current
construction project).
Spacing of interchange Nos. 5 and 6 in the southbound direction is very
short distance (i.e. ∼300 feet).
Speeds were posted at 65 miles per hour.
Edge drop-off was noted in some locations (excepted to be addressed in
current construction project).
There are no reflectors imbedded in the pavement for lane or edge
markings.
Lack of “Low Salt Area” signs exist on the corridor and it is suspected to
be a low salt zone (this was later confirmed).
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I-495 Middleborough Road Safety Audit
ANALYSIS
In completing the RSA of I-495 in Middleborough, findings were compiled from the field
audits, the review of the data input provided by team members. The following sections
summarize the results from each of the key components of the assessment.
The section of I-495 under study is approximately 8 to 9 miles in length with two lanes
per direction separated by a median. A portion (approx. 4 miles) of the study section of
the corridor beginning approximately 2,200 feet south of Interchange No. 3 to
Interchange No. 2 has a heavily vegetated median with thrie-beam guardrail installed
along both sides of the median within a few feet of the paved surface. From the point
where the thrie-beam guardrail ends south of Interchange No. 3 to approximately 2,200
feet north of Interchange No. 3 (a distance of 4,400 feet), a 4-rope Brifen system with
socketed posts was installed in the median approximately 8 to 10 feet off the northbound
edge of pavement and approximately 11 feet off the edge line. This cable barrier was
installed in November 2006. The cost for installing the Brifen high tension cable system
on I-495 including the end treatments and socketed posts was $170,000. Posts for this
installation were set at approximately 10 foot spacing. Between November 2006 and
April 2008 (16 months) when the barrier was in place, there were only 4 recorded hits.
From the northern end of the cable barrier to the treed median just north of Interchange
No. 6, the median is open for the most part and fairly flat. Exceptions are in the vicinity
of bridge columns where short section of rail has been installed.
Figure 2 - Brifen barrier system installed south of Interchange No. 3
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Based on the MassHighway permanent count station data (Station No. 725), the
roadway carries on average approximately 55,000 vehicles per day while during the
summer the volume exceeds 75,000 vehicles per day. Within the study section there are
4 interchanges. As illustrated in Figure 6, the spacing between Interchange Nos. 5 and
6 in the southbound direction is relatively short (∼300 feet). The spacing in the
northbound direction is approximately 2,600 feet from the on-ramp to the off-ramp.
Spacing between the other interchanges is at least one mile.
The existing unpaved median section ranges in width but is close to 45-50 feet along
much of its length. The median is open, grassed with slopes away from the pavement at
what appears to be flatter than 6:1 for the most part. A closed drainage system is
located in approximately the center of the median with paved waterways periodically
located at the pavement edge connecting to the center ditch or catch basin.
It should be noted that a rehabilitation project has been underway since the Spring 2008
for the particular section under study. In addition to resurfacing, the inside shoulder will
be widened slightly and a rumble strip installed. The unpaved portion of the median will
be regraded so edge drop-offs are expected to be eliminated. The rehabilitation project
is progressing and is expected to be substantially complete in 2009.
Figure 3 - I-495 section between Interchange Nos. 3 and 4 –
No Barriers and Relatively Flat Median
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Data available as part of the MassHighway crash records system indicated that between
2004 and 2007, there were 79 reported crashes related to the median. Of the 79, 20
percent or 16 were identified as cross-median crashes. The 16 cross-median crashes
resulted in personal injuries in 69% of the crashes. There were two fatal crashes that
were reported. These were classified as median related but not cross-median crashes.
In most crashes, the cited cause for the cross-median crashes were either the driver
“swerving” or failing to stay in proper lane. There were a number of crashes related to
“falling asleep or fatigue” (23%) as well as weather related (17%) resulting in wet road
surface. Eleven of the sixteen (69%) cross-median crashes were initiated in the
southbound direction.
Conditions that were noted in the crash reports varied. A number of the crashes
occurred in the area between Interchange Nos. 4 and 5. There were no predominant
factors or causes for the crashes. Included were inattention or equipment problems in
addition to the previously noted causes.
Figure 4 - Parking “stay awake” area exist in northbound and
southbound sections south of Interchange No. 4
As shown in Figure 6 is the section between the Interchange No. 6 southbound on-ramp
and Interchange No. 5 southbound off-ramp. There is approximately 300 feet of weave
distance in this section with fairly high traffic movements in this area.
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Figure 5 - Northbound curve at Interchange No. 5 off-ramp and on-ramp
Figure 6 - Southbound weave section between Interchange Nos. 6 and 5.
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I-495 Middleborough 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-495 in the
Middleborough 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
Median is “open” from north of Interchange No. 3 (Route 28)
to just north of Interchange No. 6 (Route 44) with 6:1 slopes
or flatter and considered as easily crossable
F
Narrow inside shoulder without rumble strip (to be installed
as part of rehab project)
E
Short accel/decel lanes marked
D
Multiple parking area access/egress points
B
Close spacing of Interchange Nos. 5 & 6
D
Peak period ramp queuing – Interchange Nos. 5 & 6
B
Noticeable edge drop-offs – could affect recovery (regrading
is expected to occur as part of rehab project)
C
Dark route perception
C
Curve in northbound direction at Interchange No. 5
C
Low salt area - not signed
B
Given the high volume, the high number of median entries and judged as easily
crossable, the “open” median factor was assigned a high risk factor – ‘F’. 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 median and enter the opposing
direction of flow. The median is relatively narrow and fairly flat in addition to being
devoid of any obstruction (i.e. vegetation) that may prevent a crossing.
In addition to the median character, the condition of the roadway at the time of the audit
included a narrow inside paved shoulder, no rumble strip and no lane delineators (i.e.
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reflective markers). The ongoing construction project will improve the shoulder and
include the installation of the rumble strips in both the inside and outside shoulders and
embedded reflectors in the lane line.
It was noted by the RSA team that the route is noticeably dark during non-daylight
periods and combined with the low level of motorist guidance via markings and signs,
there is an increased risk particularly in the vicinity of the interchanges and locations
where vehicle merging occurs such as the parking/rest areas. The existing cable barrier
posts include reflectors. While lighting was suggested as an option, it was also noted by
RSA team members that it is a maintenance concern and cost issue as well. Installation
costs aside, maintenance costs for tower system are approximately $2,000 per unit.
There was not a consensus of the RSA team on the lighting issue.
Improving markings on the acceleration/deceleration lanes including lengthening the
markings is an alternative. Signage is another option. The need for greater motorist
caution and awareness was particularly noted in the vicinity of Interchange Nos. 4, 5 and
6. These could involve improved notice of merging traffic, considering YIELD signs on
the entrance ramps and information relative to the potential vehicle queuing on exit
ramps.
Finally, much of the road section under study is a LOW SALT AREA and signs are not in
place.
Suggested actions identified are intended to reduce the injuries and fatalities resulting
from cross-median crashes and those related to other types of crashes as well. Given
the objective of this specific RSA program is focused on cross-median crashes and
safety risk, the initial action considered was whether a median barrier should be
installed. Later in the report, additional actions to consider in enhancing safety
conditions and addressing the noted factors are outlined.
•
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 without a barrier are
worse than if the barrier were in place.
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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
 Narrow median
 History of cross-median crashes
 High risk of catastrophic event
These items have been reviewed relative to the I-495 section under study. Figure 7
presents a review of the corridor in relation to the median warrant criteria presented in
the AASHTO RDG4. As can be seen in the diagram, with the median (as measured from
edge line to edge line) is approximately 47-52 feet and a volume of over 50,000 vehicles
on an average day, the intersection of the two items is in the area of the chart where a
barrier can be “considered”. With this highway being a major route to the Cape, summer
flows exceed 75,000 vehicles per day.
In addition to the chart and related warrant criteria, which is a guideline, further
consideration was given to the following:
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The high volume presents a likelihood of greater number of errant vehicles
entering the median,
A fairly high number of median entries (80) over the three (3) year period and
the median appears to be very crossable. Twenty percent (20%) of the
median crashes were classified as “cross-median”.
The route was perceived as “dark” with a high late night high percent (44%)
of report crashes (the nature of travel by tourists and day trippers add to late
night traveling).
Weather conditions also appear to have an effect (possibly in combination
with the dark, late night driving) in the median and cross-median crashes.
Consequently, based on the analysis of the data, the field drive-thru and discussion of
the conditions by the RSA team members, it was suggested that a median barrier, while
impacting maintenance costs along the corridor, be installed in the sections of this route
that are currently open. The selection of the barrier is discussed in greater detail in the
next section followed by the complete set of I-495 RSA recommendations.
4
American Association of State Highway and Transportation Officials, Roadside Design Guide,
Washington, D.C., 2002, Chapter 6 Update 2006.
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80
Summer
Daily
Volume
AVERAGE DAILY TRAFFIC
(thousands)
70
BARRIER
RECOMMENDED
60
BARRIER
CONSIDERED
50
Average
Traffic
Volume
40
BARRIER
OPTIONAL
30
20
10
0
0
10
20
30
40
50
MEDIAN WIDTH
(feet)
Ref: AASHTO Roadside Design Guide, Chapter 6 Update, 2006
60
70
intersection of volume
with median width
Median Barrier Warrant Analysis
I-495 Road Safety Audit
Middleborough, Massachusetts
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Framingham, Massachusetts
Figure 7
I-495 Middleborough Road Safety Audit
A. Barrier Selection
Once a decision is made to install a barrier, the type must be determined. There are a
number of barrier types that can be considered in addressing the median cross-over
crashes. These include the following:
♦
♦
♦
♦
Weak post W-Beam
Box Beam
Generic Low Tension Cable
High Tension Cable Barrier
♦ Strong post W-Beam
♦ Thrie Beam
♦ Concrete (Jersey)
In deciding on the type of barrier, there are a number of criteria suggested in the
AASHTO Roadside Design Guide5. These criteria used in selecting a barrier type are
included in Table 5.
Criteria
TABLE 5
CRITERIA FOR BARRIER SELECTION
Comments
1. Performance Capability
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 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.
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 highperformance 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.
5
American Association of State Highway and Transportation Officials, Roadside Design Guide, Washington,
D.C., 2002, Chapter 6 Update 2006.
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Based on extensive research and trials over the past five years, the high tension cable
barrier system has become more prominent in the U.S. The cable (flexible) barrier has
its advantages from a cost and aesthetic perspective, 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.
In addition to the cable barrier systems, the alternative types of guardrail were reviewed
for potential application on this route. 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 somewhat similar though
the thrie-beam has a higher cost. 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 or areas with limited median widths available. As a
result of this review, it was determined that the median barrier options that are valid for
consideration for I-495 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:
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Barrier hits per mile
Frequency of hits
Cost recovery
Cable downtime
Repair effect on traffic
Maintaining tension with cable system
Mowing median
Final selection of the barrier type should be based on the costs, physical condition of the
median, the ability to maintain a recovery zone, likely maintenance or repair
requirements, and compatibility with future planned pavement 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.
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This barrier type can be installed on slopes of 6:1 or flatter with little constraint on
placement. There are certain systems (Brifen and Gibraltor 4 rope) that have been
approved for slopes as steep as 4:1 as of this writing. The existing cable is the Brifen 4rope system and appears to be installed sufficiently away from the paved surface so as
to maintain a clear zone and to minimize the number of cable ‘hits’.
3 Cable CASS System on Route 213
4 – Rope Brifen System on I-495
Guardrail
The guardrail could be placed in the median where slopes are 10:1 or flatter 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. It may be possible to install a single line of double faced barrier a greater
distance from the pavement edge in this specific project area.
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. The W-beam rail is a lower cost option compared to the thrie-beam, however,
there is slightly greater deflection with the W-beam.
TABLE 6
COMPARISON PER MILE COSTS
Cable vs. Guardrail
Costs/Mile
Cable
W-beam
Thrie beam
MS Transportation Systems, Inc.
$144,000
$171,000
$213,000
Page 18
I-495 Middleborough 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. These actions are intended to eliminate the
chance of cross-median crashes as well as reduce the severity of all crashes and
improve the overall safety condition of this section of I-495 in Middleborough. 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 recommendation is to install a cable barrier in the median locations where it is
currently “open”. In total, approximately 6.5 miles of barrier would be installed. While
ongoing research would indicate a desire to have the barrier located where a deflection
of up to 16 feet can be accommodated without encroaching into an opposing travel lane,
the existing cable barrier system is located approximately 8 to 10 feet off the pavement
edge. The performance of the existing cable barrier and its placement appears at this
time to be satisfactory with a relatively low number of hits and no deflections into the
travel way. With the current rehabilitation project, the inside shoulder will be widened by
approximately 2 feet in order to accommodate a rumble strip. While field confirmation
will be needed, it is thought that the existing barrier could remain in its current location at
this time. If the actual distance between the barrier and the travel lane ends up less than
11-12 feet, then relocating the barrier may be a more prudent option. This can be
monitored in the future and if its placement becomes an issue as illustrated by the
frequency of “hits” or its deflection, it could be relocated.
It is suggested that the new cable barrier location, however, be placed approximately in
the center of the median which would allow for a balanced amount of recovery zone in
each direction as well as provide a greater distance to meet the estimated maximum
deflections of the barrier from both direction of a “hit”. Based on the assumed unit cost
of $144,000 per mile, the estimated implementation cost for extending the cable barrier
is $936,000. There would be additional costs incurred if the existing barrier needs to be
relocated.
Several short term actions are recommended as well as including short term signage
and delineation improvements are included in the recommendation. Several of them
such as the widening of the inside shoulder, installing a rumble strip and addressing
edge drop-offs through filling and smoothing the grade are being completed as part of
the current rehabilitation project.
MS Transportation Systems, Inc.
Page 19
I-495 Middleborough Road Safety Audit
Risk Factor
Median is “open” from north of
Interchange No. 3 (Route 28) to
just north of Interchange No. 6
(Route 44) with 6:1 slopes or
flatter and considered as easily
crossable
TABLE 7
SUMMARY OF RECOMMENDATIONS
Risk
Recommended
Rating
Action
F
ƒ Install new cable barrier north of
the existing barrier for
approximately 6.5 miles
Estimated Cost
Estimated
Timeframe
ƒ Short to
medium
term
$936,000
Narrow inside shoulder without
rumble strip
E
ƒ Widen shoulder
ƒ Install rumble strip
n/a1
n/a1
Short accel/decel lanes marked
D
ƒ Improve markings
$1,0002
ƒ short term
Multiple parking area
access/egress points
B
ƒ Install supplemental warning
signs (3)
ƒ Install entrance ramp YIELD
signs (3)
ƒ Consider closing one of parking
areas in southbound direction
$1,500
ƒ short term
ƒ short term
Close spacing of Interchange
Nos. 5 & 6
D
To be determined
(TBD)
ƒ medium
term
$30,000
ƒ short term
$1,500
ƒ short term
$5,000
TBD
ƒ short term
ƒ long term
n/a1
ƒ short term
Would be
approximately 1-2%
of future paving
project cost
ƒ long term
$10,3003
See above
ƒ short term
ƒ short term
TBD
ƒ long term
B
ƒ Install warning signs (B) see
Figure 8
ƒ Queue detectors and electronic
signs
Noticeable edge drop-offs –
could affect recovery
C
ƒ Regrade off pavement area
ƒ Add angled safety edge
C
$1,000
ƒ Install overhead warning signs
(A) see Figs. 8 & 9
ƒ Install YIELD signs (4) on
entrance ramps
Peak period ramp queuing –
Interchange Nos. 5 & 6 and
“merging traffic”
Dark route – rural character
ƒ currently
being
addressed
in on-going
construction
ƒ Add flexible, reflective delineator
posts
ƒ Improve markings at
interchanges
ƒ Consider lighting at major
interchanges
Curve in northbound direction
at Interchange No. 5
C
ƒ Install flexible delineator posts
(assume 2,500 feet)
$1,5003
ƒ short term
Low salt area - not signed
B
ƒ Install new signs (assume 6)
$3,000
ƒ short term
1
2
3
4
included in ongoing rehabilitation project
example of modified marking plans depicted in Appendix could be incorporated as part of future marking maintenance operation.
Depending on timing of barrier installation, posts may or may not be needed or desired.
Field measurements of acceleration in lane lengths should be done to verify inadequate distance prior to installation.
MS Transportation Systems, Inc.
Page 20
I-495 Middleborough Road Safety Audit
Examples of additional motorist information and warning signs and the possible
placement to be considered for application are shown in Figures 8 and 9. The RAMP
EXPECT OFF – BACKUPS AT EXIT 6 (B) sign should be placed approximately ½ mile
prior to the Exit 6 NB off-ramp. The two warning signs (A) of merging traffic would be
installed approximately 1,000 feet prior to Exit 6 in the southbound direction and ¾ of a
mile prior to Exit 5 in the northbound direction.
While the RSA team members agreed that the parking (rest) areas were beneficial, the
two areas in the southbound direction are closely spaced with the first one just south of
Interchange No. 4. Eliminating one of the areas (preferably the northernmost one to
increase spacing between the interchange and rest area) would reduce the numbers of
diverge-merge points in this short length. It is recommended that one of the southbound
rest areas be closed. Also, the exits from the parking areas should have YIELD signs
installed.
The factors surrounding the interchanges (i.e. spacing between No. 5 and 6, delineation
of acceleration-deceleration lanes, ramp queuing) can be addressed through signage
and improved markings. Examples of markings are included in the Appendix. It was
noted that the level of markings may be the result of inadequate outside shoulder width
maintained though the interchange. On-ramps without adequate acceleration lane
lengths should also have YIELD signs installed. The adequacy of the acceleration lanes
should be field verified as the accuracy of the available plans was limited.
At minimum, this should be reviewed in detail and the extent to which the delineation of
both acceleration and deceleration lanes can be enhanced. If the shoulder width is
inhibiting better delineation, then long term modifications should be considered as part of
future rehabilitation/reconstruction projects.
MS Transportation Systems, Inc.
Page 21
MERGING
TRAFFIC
XXXX FEET
SIGN A (example)
EXPECT OFFRAMP BACKUPS
AT EXIT 6
SIGN B
Note 1: Sign A in the southbound direction will be installed on a full
span truss structure 1,000 feet prior to Exit 6 along with relocating
the Exit 6 guide sign. In the northbound direction, it would be a
cantilever overhead structure 3/4 mile prior to Exit 5.
Note 2: Sign B will be roadside structure.
CONCEPTUAL ONLY NOT TO SCALE
Potential Sign Legends
I-495 Road Safety Audit
Middleborough, Massachusetts
MS Transportation Systems, Inc.
Framingham, Massachusetts
Figure 8
A
Interchange No. 6
B
Interchange No. 5
A
LEGEND
A - (see Figure 8)
B - (see Figure 8)
CONCEPTUAL ONLY NOT TO SCALE
Potential Sign Placement Interchanges 5 & 6
I-495 Road Safety Audit
Middleborough, Massachusetts
MS Transportation Systems, Inc.
Framingham, Massachusetts
Figure 9
I-495 Middleborough Road Safety Audit
Appendix
•
•
•
•
•
•
•
MS Transportation Systems, Inc.
RSA Meeting Agenda
RSA Team List
Median Crash Diagram
Crash Summary Data
Traffic Volume Data
Example of AccelerationDeceleration Lane Markings
Low Salt Zone Plan
Page 24
Road Safety Audit
Middleboro – Interstate 495
Meeting Location: MassHighway District 5 Office
1000 County Street, Taunton
Friday, April 18, 2008
10:30 AM – 12:30 PM
Type of meeting:
Cross Median – Road Safety Audit
Attendees:
Invited Participants to Comprise a Multidisciplinary Team
Please bring:
Thoughts and Enthusiasm!!
10:30 AM
Welcome and Introductions
10:45 AM
Introduction to Road Safety Audits and Cross Median Crashes
11:00 AM
Review of Site Specific Material
• Crash & Volume Summaries– provided in advance
• Existing Geometries and Conditions
• Video and Images
11:30 AM
Completion of RSA
• Identification of Safety Concerns – using RSA Prompt List as a guide
• Identification of Possible Countermeasures
12:30 PM
Adjourn for the Day – but the RSA has not ended
Instructions for Participants:
• Before attending the RSA on April 18th participants are encouraged to drive
Interstate 495 in Middleboro (Interchanges 2-6) 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-495 - April 18, 2008
MassHighway District 5 Offices, Middleborough MA
Attendance List
Name
Agency/Dept.
Email
William Scully
MS Transportation Systems
bscullyjr@mac.com
Jim Hadfield
SRPEDD
jhadfield@srpedd.org
Alolade Campbell
MHD District 5
alolade.campbell.mhd.state.ma.us
Timothy Kochan
MHD District 5
timothy.kochan@mhd.state.ma.us
Daniel Mulkern
State Police Troop D
daniel.mulkern@state.ma.us
Donald Pettey
MHD District 5
donald.pettey@mhd.state.ma.us
Lisa Scheltzbaum
MHD Safety Management
lisa.schletzbaum@mhd.state.ma.us
Robert Gregory
MHD District 5 Traffic
robert.gregory@mhd.state.ma.us
Thomas Broderick
MHD Safety Management
thomas.broderick@mhd.state.ma.us
Hardy Patel
Neil Boudreau
MHD Highway Design
MHD Traffic & Safety
hasmukh.patel@mhd.state.maus
neil.boudreau@mhd.state.ma.us
MS Transportation Systems, Inc.
R
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Crash IDs
between 13-25
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I-495 Interchange Median Crashes in Middleborough
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28
29
MAI
Median, Fatal Crash
Principal Arterial
Median, Non-Fatal Crash
Minor Arterial
Median, Not Reported
Collector
Median Barrier **
Local
ST R
EE T
T RE E T
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Crash IDs
between 33-69
T
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3
32
70
71
72
75
76
77
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74
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AR
W
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** Cable median barrier installed
11/06. No further reported crossover
RO
ND section.
A
crashes in median barrier
L
H
30
EH
AM
HIGH
L
* 2007 crash file has not yet been closed.
G
HI
E
MILLER STREET
R
Interstate
0.8
RO
V
Major Roads
Cross Median, Non-Fatal Crash
T
0.4
G
W
AR
Municipal Boundary
0
T
ET
RE
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E
26
27
ST
LAKEVILLE
INC
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TR
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ID
N
HA
ST R EE T
Type of Median Crash 2004-2007 *
PR E
C
495
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VA
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BE DF O R
Legend
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78
R
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MASSACHUSETTS HIGHWAY SAFETY DIVISION
CRASH SUMMARY
ROADWAY:
I-495
STUDY PERIOD:
NO.
1/1/2004
CRASH NUMBER
TO
12/31/2007
CITY:
MIDDLEBOROUGH
LOCATION:
EXIT#3; EXIT#4; EXIT#5
TRAVEL
LIGHT
WEATHER
ROAD
REASON FOR
VEHICLE
MEDIAN OR CROSS
DRIVER CONTRIBUTING
CRASH
DIRECTION
CONDITION
CONDITION
SURFACE
RUNNING OFF ROAD LEFT
MOVEMENT
MEDIAN CRASHES
CAUSE
SEVERITY
1
1806565
NB
Daylight
Clear
Dry
Crash avoidance with vehicle entering from on-ramp
N/B Travel Lane to S/B Travel Lane
Cross Median
Failure to yield at ramp
Property Damage Only
2
2188767
NB
Daylight
Clear
Dry
Due to sun blurred vision vehicle struck right guardrail
Travel Lane to Right Guardrail to Median Guardrail
Median
Glare
Property Damage Only
3
2283012
NB
Daylight
Clear
Dry
Tailgating vehicle caused other vehicle to strike median guardrail
Travel Lane to Median Guardrail to the Right Guardrail
Median
Swerving or avoiding due to vehicle in roadway Property Damage Only
4
1928196
NB
Dark - Not Lighted
Clear
Dry
Suffered from fatigue and vehicle left tires exit into median
Travel Lane to Near Median to Right Guardrail to Near Median to Travel Lane
Median
Fatigued/Asleep
Property Damage Only
5
1975542
SB
Dark - Not Lighted
Clear
Dry
Unknown reason vehicle veered out of travel lane
Travel Lane to Median
Median
Failure to keep in proper lane
Property Damage Only
6
1889195
NB
Dark - Not Lighted
Rain
Wet
Crash avoidance with vehicle
N/B travel lane to S/B Right Guardrail
Cross Median
Failure to keep in proper lane
Property Damage Only
7
1900060
NB
Dark - Not Lighted
Clear
Dry
Distracted due to cell phone usage and vehicle overturned in the median
N/B Travel Lane to S/B Left Breakdown Lane
Median
Distracted due to cell phone
Non-Fatal Injury
8
1961268
NB
Dark - Not Lighted
Clear
Dry
Distracted due to cell phone usage and vehicle veered left off the roadway
Travel Lane to Median Crash Attenuator
Median
Distracted due to cell phone
Property Damage Only
9
2114534
NB
Dawn
Clear
Dry
Fallen asleep and vehicle run off to the median
Travel Lane to Median to Travel Lane to Median Guardrail to Right Guardrail to MMedian
Fatigued/Asleep
Property Damage Only
10
1992605
SB
Daylight
Clear
Dry
Tractor tire blew out and flying debris caused windshield to be broken
Travel Lane to Median
No Improper Driving
Property Damage Only
11
1992962
SB
Dark - Not Lighted
Clear
Dry
Vehicle left front tire blew out
S/B Travel Lane to N/B Right Guardrail
Cross Median
No Improper Driving
Property Damage Only
12
2264887
SB
Dark - Not Lighted
Clear
Dry
Lost control of vehicle and overturned
S/B Travel Lane to S/B Median to S/B Right Guardrail to N/B Right Guardrail
Cross Median
Swerving in roadway
Non-Fatal Injury
13
2133977
SB
Daylight
Snow
Ice
Lost control of vehicle on wet roadway
S/B Travel Lane to N/B Travel Lane
Cross Median
Driving too fast for condition
Non-Fatal Injury
14
1805987
SB
Daylight
Clear
Dry
Fallen asleep and vehicle drifted into median
Travel Lane to Near Median to Right Guardrail to Travel Lane
Median
Fatigued/Asleep
Non-Fatal Injury
15
1889198
SB
Dark - Not Lighted
Rain
Water
Vehicle hit standing water and spun into right guardrail
Travel Lane to Right Guardrail to the Median Guardrail
Median
Driving too fast for condition
Property Damage Only
16
1992917
SB
Dark - Lighted
Clear
Dry
After mechanical failure vehicle overturned in the median
Travel Lane to Far Median
Median
No Improper Driving
Property Damage Only
Median
17
2257532
SB
Daylight
Clear
Dry
Lost control of vehicle for unknown reason
S/B Travel Lane to N/B Travel Lane and back to Median
Cross Median
Swerving in roadway
Non-Fatal Injury
18
2261063
SB
Dark - Not Lighted
Clear
Dry
Vehicle swerved into travel lane and hit other vehicle
S/B Travel Lane to N/B Travel Lane
Cross Median
Failure to keep in proper lane
Non-Fatal Injury
19
2268763
SB
Daylight
Snow
Ice
Lost control of vehicle on wet roadway
Travel Lane to Median to Right Guardrail
Median
Swerving in roadway
Non-Fatal Injury
20
1815374
NB
Daylight
Clear
Dry
Crash avoidance with vehicle from suddenly slowing traffic
Travel Lane to Near Median
Median
Followed too closely
Non-Fatal Injury
21
1992949
NB
Daylight
Rain
Ice
Due to black ice driver swerved to the left
N/B Travel Lane to S/B Right Guardrail
Cross Median
Swerving due to slippery surface in overpass
Property Damage Only
22
1806106
NB
Dark - Not Lighted
Clear
Dry
Fallen asleep and vehicle drifted into median and overturned
Travel Lane to Near Median to Right Dirt Mound
Median
Fatigued/Asleep
Non-Fatal Injury
23
1992783
NB
Dark - Not Lighted
Clear
Dry
Suffered from fatigue and vehicle veered into median
Travel Lane to Near Median to Right Guardrail to Median
Median
Fatigued/Asleep
Non-Fatal Injury
24
1993235
NB
Daylight
Snow
Snow
Vehicle skidded on snow covered surface
Travel Lane to Right Guardrail to Middle Median
Median
Swerving due to slippery surface in roadway
Property Damage Only
Swerving or avoiding due to vehicle in roadway Property Damage Only
25
2068477
NB
Daylight
Clear
Dry
Crash avoidance with vehicle swerving into travel lane
Travel Lane to Median
Median
26
1878836
SB
Dark - Not Lighted
Clear
Dry
Lost control of vehicle
Travel Lane to Left Guardrail to the Right Guardrail
Median
Exceeded Speed Limit & Alcohol
27
2240531
SB
Daylight
Cloudy
Ice
Lost control of vehicle on ice roadway
N/B Travel Lane to S/B Travel Lane
Cross Median
Swerving due to slippery surface in roadway
Property Damage Only
28
2051446
NB
Dark - Not Lighted
Clear
Dry
Lost control of vehicle due to prescription medications
N/B Travel Lane to Attenuator to S/B Rest Area
Cross Median
Prescription Drugs
Non-Fatal Injury
29
1927650
SB
Dark - Not Lighted
Snow
Snow
Hitting slower moving vehicle rear tires
Travel Lane to Median
Median
Driving too fast for condition
Property Damage Only
30
1888471
SB
Dark - Not Lighted
Cloudy
Dry
Crash avoidance with unknown animal
S/B Travel Lane to N/B Right Shoulder Parking Rest Area Sign
Cross Median
Swerving or avoiding due to animal in roadway
Non-Fatal Injury
31
1884852
SB
Dark - Not Lighted
Cloudy
Dry
Distracted due to cell phone usage and vehicle veered to the left striking a mile marker sign
S/B Travel Lane to N/B Right Shoulder Tree Line
Cross Median
Distracted due to cell phone
Non-Fatal Injury
32
2015829
SB
Dark - Not Lighted
Fog, Smog, Smoke
Wet
Fallen asleep and vehicle overturned
Travel Lane to Median Guardrail to Right Guardrail
Median
Fatigued/Asleep
Non-Fatal Injury
33
1805512
SB
Daylight
Clear
Dry
Operator reached for something in the car and vehicle hit median guardrail
Travel Lane to Left Guardrail to Right Guardrail to Trees
Median
Inattention
Non-Fatal Injury
34
1806134
SB
Dawn
Clear
Dry
Fallen asleep and vehicle drifted into median and fishtailed
N/B Travel Lanes to S/B Travel Lanes
Cross Median
Fatigued/Asleep
Non-Fatal Injury
35
1927649
SB
Dark - Not Lighted
Blowing Sand, Snow
Snow
Lost control of vehicle due to low visibility
Travel Lane to Median Guardrail Buried End to Median Trees
Median
Visibility Obstructed
Property Damage Only
36
1928053
SB
Dark - Not Lighted
Clear
Dry
Crash avoidance with deer
Left Travel Lane to Trees in the Median
Median
Swerving or avoiding due to animal in roadway
Non-Fatal Injury
37
1928064
SB
Dark - Not Lighted
Clear
Dry
Fallen asleep and vehicle drifted into median
Travel Lane to Center Median
Median
Fatigued/Asleep
Property Damage Only
38
1992808
SB
Daylight
Clear
Dry
Vehicle struck a piece of metal debris and swerved into median
N/B Travel Lanes to S/B Travel Lanes
Cross Median
No Improper Driving
Non-Fatal Injury
39
1993329
SB
Dark - Not Lighted
Clear
Snow
Lost control of vehicle and overturned
Travel Lane to Median to Trees in the Median
Median
Exceeded Speed Limit
Property Damage Only
40
1993373
SB
Daylight
Clear
Ice
Vehicle skidded on ice covered surface
Travel Lane to Median
Median
Swerving due to slippery surface in roadway
Property Damage Only
41
1993376
SB
Daylight
Clear
Ice
Vehicle slowed for an accident and skidded on ice covered surface
Travel Lane to Median
Median
Followed Too Closely
Property Damage Only
42
2149183
SB
Daylight
Cloudy
Wet
Fallen asleep and vehicle drifted off the road
Right Travel Lane to Center Median
Median
Fatigued/Asleep
Property Damage Only
43
2166448
SB
Daylight
Clear
Dry
Lost control of vehicle, spun around and stroke an another vehicle
Travel Lane to Median Guardrail
Median
Failure to keep in proper lane
Non-Fatal Injury
44
2051607
SB
Dusk
Rain
Wet
Suffered from fatigue and vehicle hit median guardrail
Travel Lane to Median Guardrail
Median
Fatigued/Asleep
Property Damage Only
45
1993655
SB
Dark - Not Lighted
Clear
Dry
Vehicle changed lanes to an already occupied lane and caused another vehicle to overturn
Travel Lane to Median
Median
Operating vehicle in reckless manner
Non-Fatal Injury
46
1884918
NB
Daylight
Clear
Wet
Vehicle struck a piece of metal debris
Travel Lane to Near Median
Median
No Improper Driving
Property Damage Only
47
1925965
NB
Dark - Not Lighted
Cloudy
Dry
Fallen asleep and vehicle overturned
Travel Lane to Near Median to Median Guardrail
Median
Fatigued/Asleep
Fatal Injury
48
1927900
NB
Dark - Not Lighted
Clear
Dry
Vehicle tried to avoid deer and overturned in the median
Second Travel Lane to Median
Median
Swerving or avoiding due to animal in roadway
Non-Fatal Injury
49
2239510
NB
Dark - Not Lighted
Clear
Dry
Fallen asleep and vehicle went off to the median
Travel Lane to Median Embankment to Trees in the Median
Median
Fatigued/Asleep
Property Damage Only
50
2264544
NB
Dawn
Rain
Wet
Lost control of vehicle and overturned
Travel Lane to Median Guardrail
Median
Exceeded Speed Limit
Property Damage Only
51
1902363
SB
Dark - Not Lighted
Clear
Dry
Unknown vehicle changed lanes and stroked other vehicle on the right
Second Travel Lane to Median
Median
Swerving or avoiding due to vehicle in roadway Property Damage Only
52
1992907
SB
Daylight
Clear
Dry
Distracted due to cell phone usage and vehicle went off the roadway
N/B Travel Lanes to S/B Travel Lanes
Cross Median
Distracted due to cell phone
Non-Fatal Injury
53
2188741
SB
Daylight
Clear
Dry
Crash avoidance with metal object on the roadway
Travel Lane to Median Guardrail
Median
Swerving or avoiding due to object in roadway
Property Damage Only
54
2220899
SB
Daylight
Clear
Dry
Vehicle tried to avoid tire debris on the roadway and overturned
Travel Lane to Median
Median
Swerving or avoiding due to object in roadway
Property Damage Only
55
1806609
NB
Dawn
Clear
Dry
Lost control of vehicle for unknown reason
Second Travel Lane to Median to Right Wooded Area
Median
Swerving in roadway
Property Damage Only
56
1809088
NB
Daylight
Clear
Dry
Reached for cigarettes at the drivers door side packet and vehicle struck right guardrail
Travel Lane to Right Guardrail to the Far Wooded Median
Median
Inattention
Fatal Injury
57
1887095
NB
Daylight
Clear
Dry
Vehicle changed lanes to an already occupied lane and caused another vehicle to enter median
N/B Travel Lanes to S/B Travel Lanes
Cross Median
Failure to keep in proper lane
Non-Fatal Injury
Non-Fatal Injury
MASSACHUSETTS HIGHWAY SAFETY DIVISION
CRASH SUMMARY
ROADWAY:
I-495
STUDY PERIOD:
NO.
1/1/2004
CRASH NUMBER
TO
12/31/2007
CITY:
MIDDLEBOROUGH
LOCATION:
EXIT#3; EXIT#4; EXIT#5
TRAVEL
LIGHT
WEATHER
ROAD
REASON FOR
VEHICLE
MEDIAN OR CROSS
DRIVER CONTRIBUTING
CRASH
DIRECTION
CONDITION
CONDITION
SURFACE
RUNNING OFF ROAD LEFT
MOVEMENT
MEDIAN CRASHES
CAUSE
SEVERITY
58
1887126
NB
Dark - Not Lighted
Cloudy
Dry
Suffered from fatigue and vehicle drifted to the left and overturned
Travel Lane to Median to Median Embankment
Median
Fatigued/Asleep
Property Damage Only
59
1927874
NB
Dark - Not Lighted
Clear
Dry
Fallen asleep and vehicle traveled into median
Travel Lane to Median to Trees in the Median
Median
Fatigued/Asleep
Property Damage Only
60
1992773
NB
Daylight
Clear
Dry
Lost control of vehicle
Travel Lane to Median to Trees in the Right Shoulder
Median
Swerving in roadway
Non-Fatal Injury
61
1992804
NB
Daylight
Clear
Dry
Vehicle steering problem
Travel Lane to Median to Trees in the Right Shoulder
Median
Operating defective equipment
Property Damage Only
Non-Fatal Injury
62
1993333
NB
Dark - Not Lighted
Cloudy
Ice
Vehicle skidded on ice covered surface and overturned
First travel lane to Trees in the Median
Median
Swerving due to slippery surface in roadway
63
1993340
NB
Daylight
Clear
Ice
Vehicle skidded on ice covered surface and overturned
First travel lane to Median Embankment to Trees in the Median
Median
Swerving due to slippery surface in roadway
Non-Fatal Injury
64
1993379
NB
Daylight
Blowing Sand, Snow
Ice
Vehicle skidded on ice covered surface and overturned
Travel Lane to the Wooded Median
Median
Swerving due to slippery surface in roadway
Non-Fatal Injury
65
2051288
NB
Daylight
Clear
Dry
Unknown reason vehicle veered into median and overturned in the right shoulder
Travel Lane to Median to Right Shoulder Tree Line
Median
Failure to keep in proper lane
Non-Fatal Injury
66
2160073
NB
Daylight
Sleet, Hail, Freezing Rain Ice
Vehicle skidded on ice covered surface and fishtailed
Right Travel Lane to Median Cable Safety Fence
Median
Swerving due to slippery surface in roadway
Property Damage Only
67
2220897
SB
Dark - Not Lighted
Clear
Dry
Lost control of vehicle
Travel Lane to Median Guardrail to Right Guardrail
Median
Failure to keep in proper lane
Property Damage Only
68
2101480
NB
Daylight
Cloudy
Dry
Operator get distracted and ran off road to the left
Travel Lane to Median
Median
Inattention
Property Damage Only
69
2228695
NB
Dark - Not Lighted
Clear
Dry
Vehicle tried to avoid trash barrel on the roadway and skidded into the left lane
Travel Lane to Median
Median
Swerving or avoiding due to object in roadway
Property Damage Only
70
2015815
NB
Daylight
Clear
Dry
Lost control of vehicle and overturned
Travel Lane to Median Guardrail
Median
Failure to keep in proper lane
Non-Fatal Injury
71
1899775
NB
Dark - Not Lighted
Snow
Ice
Vehicle skidded on snow covered surface
Travel Lane to Median to Trees in the Median
Median
Swerving in roadway
Property Damage Only
Non-Fatal Injury
72
1992579
SB
Daylight
Cloudy
Dry
Lost control of vehicle
Travel Lane to Median to Right Shoulder Embankment
Median
Swerving in roadway
73
2015698
SB
Daylight
Clear
Dry
Fallen asleep and vehicle ran off road to the left
Travel Lane to Trees in the Median
Median
Fatigued/Asleep
Property Damage Only
74
2236205
NB
Dark - Not Lighted
Clear
Dry
Fallen asleep and vehicle went off to the median
Travel Lane to Beginning of Median Guardrail
Median
Fatigued/Asleep
Non-Fatal Injury
Travel Lane to Median Guardrail Buried End to Median Embankment to Large Tre Median
Exceeded Speed Limit
Non-Fatal Injury
Non-Fatal Injury
75
1889267
SB
Dark - Not Lighted
Cloudy
Dry
Driver inattentive of roadway and vehicle drifted to the left
76
1900048
SB
Dawn
Clear
Dry
Operator looked down in the vehicle and veered into the median and overturned
Travel Lane to Median to Median Embankment
Median
Inattention
77
1928248
NB
Daylight
Clear
Dry
Vehicle was cut-off by unknown vehicle and overturned
Travel Lane to Median Embankment
Median
Swerving or avoiding due to vehicle in roadway Non-Fatal Injury
78
1992964
SB
Dark - Not Lighted
Clear
Dry
Suffering from fatigue and vehicle drifted to the left and overturned
Travel Lane to Median
Median
Fatigued/Asleep
Non-Fatal Injury
79
2051322
NB
Daylight
Clear
Dry
Fallen asleep and vehicle drifted into median
Travel Lane to Median Terminus in Ditch
Median
Fatigued/Asleep
Property Damage Only
LIGHT CONDITION
WEATHER CONDITION
TOTAL NO.
DAYLIGHT
DAWN
DUSK
DARK-LIGHTED
DARK-NOT LIGHTED
CLEAR
CLOUDY
RAIN
79
37
5
1
1
35
55
10
5
5
100%
47%
6%
1%
1%
44%
70%
13%
6%
6%
WEATHER CONDITION
MEDIAN OR CROSS MEDIAN
ROAD SURFACE
BLOWING SAND,
FOG, SMOG,
SLEET, HAIL,
SNOW
SMOKE
FREEZING RAIN
DRY
WET
SNOW
ICE
SNOW
WATER
MEDIAN
CROSS MEDIAN
2
1
1
57
6
4
11
1
63
16
3%
1%
1%
72%
8%
5%
14%
1%
80%
20%
SWERVING IN
SWERVING DUE TO SLIPPERY
ROADWAY
SURFACE IN ROADWAY
DRIVER CONTRIBUTING CAUSE
NO IMPROPER
EXCEEDED SPEED
FAILURE TO YIELD
FOLLOWED TOO
DRIVING TOO FAST
FAILURE TO KEEP
DRIVING
LIMIT
AT RAMP
CLOSELY
FOR CONDITION
IN PROPER LANE
5
4
1
2
3
8
1
4
7
8
6%
5%
1%
3%
4%
10%
1%
5%
9%
10%
SWERVING OR AVOIDING DUE
VISIBILITY
SWERVING OR AVOIDING
PRESCRIPTION
OPERATING DEFECTIVE
TO ANIMAL IN ROADWAY
OBSTRUCTED
DUE TO OBJECT IN ROADWAY
DRUGS
EQUIPMENT
OPERATING VEHICLE IN RECKLESS MANNER
SWERVING OR AVOIDING DUE TO VEHICLE IN ROADWAY
DRIVER CONTRIBUTING CAUSE
GLARE
VISIBILITY
INATTENTION
DISTRACTED DUE TO CELL PHONE
FATIGUED/ASLEEP
OBSTRUCTED
2
1
3
1
1
4
4
18
1
1
3%
1%
4%
1%
1%
5%
5%
23%
1%
1%
CRASH SEVERITY
PROPERTY DAMAGE
NON-FATAL
ONLY
INJURY
FATAL INJURY
41
36
2
52%
46%
3%
2007 CRASH INFORMATION ARE NOT COMPLETE
CRASH SUMMARY IS BASED ON CRASH REPORTS WITH STATE POLICE NARRATIVES
Directional Traffic Volumes along I-495, North of Route 28, Middleborough
Tuesday, September 12, 2006
2,000
1,500
Northbound Direction
Southbound Direction
1,000
500
Time of Day
PM
10
:0
0
PM
8:
00
PM
6:
00
PM
4:
00
PM
2:
00
PM
AM
12
:0
0
10
:0
0
AM
8:
00
AM
6:
00
AM
4:
00
AM
2:
00
AM
0
12
:0
0
Hourly Volume (Number of Vehicles)
2,500
I-495, Between RTE. 28 (Wareham Street) & RT 105 (Main Street) 09/12/2006
Northbound Southbound
Direction
Direction
TOTAL
Start time
12:00 AM
54
103
157
1:00 AM
53
77
130
2:00 AM
35
56
91
3:00 AM
91
65
156
4:00 AM
260
103
363
5:00 AM
942
388
1,330
6:00 AM
1,862
902
2,764
7:00 AM
2,424
1,131
3,555
8:00 AM
2,002
1,066
3,068
9:00 AM
1,536
1,022
2,558
10:00 AM
1,282
1,093
2,375
11:00 AM
1,149
1,047
2,196
12:00 PM
1,101
1,080
2,181
1:00 PM
1,204
1,124
2,328
2:00 PM
1,283
1,397
2,680
3:00 PM
1,339
1,810
3,149
4:00 PM
1,430
2,158
3,588
5:00 PM
1,201
2,181
3,382
6:00 PM
868
1,566
2,434
7:00 PM
647
1,052
1,699
8:00 PM
441
774
1,215
9:00 PM
342
575
917
10:00 PM
233
378
611
11:00 PM
118
240
358
Daily Total
21,897
21,388
43,285
Directional Traffic Volumes along I-495, Between Interchanges 4&5,
Middleborough
Tuesday, September 16, 2007
2,500
2,000
Northbound Direction
Southbound Direction
1,500
1,000
500
Time of Day
PM
10
:0
0
PM
8:
00
PM
6:
00
PM
4:
00
PM
2:
00
PM
AM
12
:0
0
10
:0
0
AM
8:
00
AM
6:
00
AM
4:
00
AM
2:
00
AM
0
12
:0
0
Hourly Volume (Number of Vehicles)
3,000
I-495, Between Interchanges 4 and 5 09/16/2006
Northbound Southbound
Direction
Direction
TOTAL
Start time
12:00 AM
54
129
183
1:00 AM
38
97
135
2:00 AM
57
47
104
3:00 AM
88
59
147
4:00 AM
295
118
413
5:00 AM
1,064
366
1,430
6:00 AM
2,029
910
2,939
7:00 AM
2,806
1,133
3,939
8:00 AM
2,315
1,100
3,415
9:00 AM
1,592
1,060
2,652
10:00 AM
1,302
1,030
2,332
11:00 AM
1,156
1,104
2,260
12:00 PM
1,183
1,028
2,211
1:00 PM
1,149
1,160
2,309
2:00 PM
1,269
1,537
2,806
3:00 PM
1,390
1,930
3,320
4:00 PM
1,439
2,389
3,828
5:00 PM
1,347
2,514
3,861
6:00 PM
946
1,709
2,655
7:00 PM
552
1,045
1,597
8:00 PM
429
804
1,233
9:00 PM
276
566
842
10:00 PM
224
372
596
11:00 PM
127
267
394
Daily Total
23,127
22,474
45,601
Example of Channelizing Line Applications for
Entrance-Exit Ramp Markings
Neutral area
Optional
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Theoretical gore point
Broken lane line markings for full length of
acceleration/deceleration lane
Channelizing
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Water
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MassHighway Low Salt Zone 2007
D5-05
0
0.1
0.2
0.3
0.4
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1 inch equals 0.8 Miles