ROAD SAFETY AUDIT
MAJOR HIGHWAY MEDIAN
CROSS-OVER CRASHES
I-495 Littleton
Prepared for
Massachusetts Highway Department
Prepared by
MS Transportation Systems, Inc.
Framingham, Massachusetts
December 2008
ROAD SAFETY AUDIT
MAJOR HIGHWAY MEDIAN
CROSS-OVER CRASHES
I-495 LITTLETON
December 2008
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 Littleton Road Safety Audit
TABLE OF CONTENTS
Page
INTRODUCTION
1
RSA PROCESS
3
ANALYSIS
7
SUMMARY OF RSA FINDINGS/POTENTIAL ACTIONS
10
RECOMMENDATIONS
14
APPENDIX
18
MS Transportation Systems, Inc.
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Route I-495 Littleton Road Safety Audit
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 and safety risk
could be affected. The team works to identify opportunities for enhancing safety and to
recommend specific enhancements that may be implemented to reduce median crossover crashes and improve the overall safety along the highway.
An RSA was conducted for the I-495 in Littleton as part of this overall effort. The
roadway section under study, shown in Figure 1, was essentially between Interchange
No. 29 at Route 2 and Interchange No. 31 at Route 119 a distance of approximately 3
miles. This section had experienced a fatal cross-median crash.
The purpose of this I-495 Littleton RSA was to assess current safety characteristics on
the highway section under study 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 and do not necessarily reflect the
official views of MassHighway.
MS Transportation Systems, Inc.
Page 1
Interchange
31
Interchange
30
495
Route 2A
Route 119
Littleton
Route 2
495
Interchange
29
- interchanges
N
Project Location
W
S
I-495 Road Safety Audit
Littleton, Massachusetts
MS Transportation Systems, Inc.
E
1 : 25,000
Framingham, Massachusetts
FIGURE 1
Route I-495 Littleton Road Safety Audit
RSA PROCESS
The overall procedures outlined in the Median Cross-Over RSA Guideline Report1 were
followed 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 20042007 period, detailed crash reports of cross-over crashes, and available record highway
plans were obtained and reviewed by the RSA consultant. 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 July 22, 2008 at the MassHighway District 3 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 Littleton Road Safety Audit:
Kathryn Cook, MassHighway, Traffic Intern
Edward Pomfred, MassHighway, Traffic Intern
Bonnie Polin, MassHighway
Sgt. Eugene O’Neill, Mass State Police
Robert Babb, MassHighway, District 3
Chris Hogan, MassHighway, District 3
William J. Scully, MS Transportation systems
(RSA Consultant)
•
Christine Breen, MassHighway, Design
Timothy White, FHWA
Lisa Schletzbaum, MassHighway, Safety
Management Unit
Mark Johnson, MassHighway, District 3
Eric Nascimento, MassHighway, District 3
RSA Team Meeting
The RSA team meeting took place on July 22, 2008 at the District 3 offices in Worcester.
The team included engineers, planners and a representative from the State Police
barrack that has jurisdiction of I-495 in Littleton. Represented were MassHighway
(Boston and District), the Federal Highway Administration (FHWA) as well as the State
1
MS Transportation Systems, Inc., Road Safety Audits, Median Cross-Over Crashes, Audit Guidelines,
Prepared for MassHighway, October 2007.
MS Transportation Systems, Inc.
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Route I-495 Littleton Road Safety Audit
Police. Contact information of the RSA team is in the Appendix. As stated previously,
overall characteristics and conditions of the study section were presented. A video and
pictures were reviewed and a discussion of the potential safety opportunities for
enhancement followed.
The major discussion at the RSA meeting centered on the fact that only one (1) of
twenty-eight median related crashes was reported as a cross-median crash and that the
current geometric design of the section under study appears to be more than sufficient to
1) have minimal or no cross-over events and 2) largely has a clear zone area where
errant motorists can safely recover or stop with relatively low damage crashes. The
short sections of mounds were noted as contributing to roll-over type of crashes
although noted by some team members, the mounds may have served to reduce the
chance of a cross-over event.
The most significant factors raised at the RSA team meeting were:
 High travel speeds and driver behavior in terms of following too closely and
decisions on changing lanes.
 Guardrails are terminated somewhat soon on the overpasses when roadside
slopes are still relatively steep for a greater distance than what is protected.
In addition, it was noted that there was limited guidance or information in delineating the
median location for motorists.
•
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
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.
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.
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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Route I-495 Littleton Road Safety Audit
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
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
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.
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Route I-495 Littleton Road Safety Audit
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 on or before July 22, 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 information. The RSA field audits took place by team members prior to the
RSA team meeting. Unfortunately, much of study section was under reconstruction at
the time of the field visits. The reconstruction project includes resurfacing and new
pavement markings. The road section near Interchange No. 30 and 31 had previously
been resurfaced. In addition to noting the reconstruction section, the field audits
identified the following:
ƒ
Three (3) travel lanes per direction are provided.
ƒ
Speed limits are posted at 65 miles per hour (mph).
ƒ
The section of road just south of Interchange No. 29 to approximately
3,000 feet north of the interchange was under reconstruction.
ƒ
The section of road that appears “finished” (north of Route 2) had a
relatively narrow inside shoulder (1-2 feet) without a rumble strip or
reflector posts along the median.
ƒ
The geometry of the highway results in a generally comfortable ride.
ƒ
The median is fairly level and open along much of the section under study
but fairly wide providing a sizeable recovery zone.
ƒ
It was noted that the guardrail on the overpass at Route 2 seems to end
abruptly in areas that the roadside slope still appears steep.
MS Transportation Systems, Inc.
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Route I-495 Littleton Road Safety Audit
ANALYSIS
In completing the RSA of I-495 in Littleton, findings were compiled from the field audits,
the review of the data, and input provided by team members. The following paragraphs
summarize the results from each of the key components of the assessment.
The section of I-495 under study is approximately 3 miles in length with three (3) lanes
per direction separated by a median. The section includes three interchanges: No. 29 at
Route 2, No. 30 at Route 110/2A and No, 31 at Route 119. There is one mile separation
between the Route 2 and Route 110 interchanges. There is a 2 mile distance between
Interchange Nos. 30 and 31. Currently, the road section near Route 2 is being
reconstructed. The project includes new pavement, markings and possibly related items
such as reflectors. The rehabilitation project is progressing and is expected to be
completed by Spring 2009.
I-495 bridges over Route 2 creating a vertical curve in combination with a slight
horizontal curve at the interchange. Speeds are posted at 65 miles per hour. The
section of highway in the area of the two interchanges north of Route 2 shows an inside
shoulder of approximately 1-2 feet in width and no rumble strip or imbedded reflectors in
place at the time of this analysis. In addition, this section of I-495 does not have the
reflective delineator posts installed alongside the median.
Figure 2 – View of the median from the northbound direction.
MS Transportation Systems, Inc.
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Route I-495 Littleton Road Safety Audit
Once north of the Route 2 interchange, there is a long straight section in the northbound
direction before entering a large radius curve on the approach to the Route 119 exit.
For the most part, the median is open and fairly flat. Exceptions are in the vicinity of
bridge columns where short sections of guardrail have been installed. The width of the
median (measured from presumed edge line to edge line) was between 92 and 95 feet.
Figure 3 Tangent section in northbound direction.
Based on the recent MassHighway traffic counts, the roadway carries on average
110,000 to 117,000 vehicles per day in the study section. Figures 4 and 5 illustrate the
directional volume over the course of the day for the sections north and south of Route
2. As can be seen in the diagrams, daily volumes exceed 110,000 south of Route 2
while are greater than 117,000 north of Route 2. While there are two distinct peak hours
(AM and PM commuter periods), there is little difference in volumes by direction. Peak
hour – peak direction volumes are between 4,500 and 5,000 vehicles.
Data available as part of the MassHighway crash records system indicated that between
2004 and 2007, there were 28 reported crashes related to the median. Of the 28, only
one crash (3.5%) was identified as a cross-median crash. The one cross-median crash
resulted in a fatality. In most crashes, the cited driver contributing cause for the crash
was non-reported. Other reasons, where cited, were either driving too fast or failing to
stay in proper lane. Weather could have been a contributing factor in six (21%) crashes
with wet road surface. Approximately half of the crashes resulted in property damage
only.
MS Transportation Systems, Inc.
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Route I-495 Littleton Road Safety Audit
Figure 4. I-495 Hourly Traffic Volumes South of Route 2
Figure 5. I-495 Hourly Traffic Volumes North of Route 2
MS Transportation Systems, Inc.
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Route I-495 Littleton 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
Littleton area were identified. In essence, the RSA team determined that only a few
factors or issues of concern exist at this time 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
“Open” roadside slopes >6:1 near Route 2 overpass
D
Open Median
C
Narrow inside shoulder without rumble strip
C
High travel speeds and driver behavior
D
Short accel/decel lanes marked
C
Limited motorists guidance of median location
C
Although the section of I-495 under study experienced significantly high traffic volumes
(>100,000 ADT), the RSA team felt the drive through the section was essentially a
“comfortable” drive without any substantive difficulties due to the overall geometry.
While there is an open median, it is wide and as evident by the low percentage of crossover crashes, appears to be sufficient in “retaining” errant motorists that enter the
median. Thus, the open median in this section currently presents a relatively low level
risk for cross-over events although the cross-median crash that did occur during the data
period resulted in a fatality. Based on infrequent occurrence yet potentially severe
result, the open median issue was rated a ‘C’.
High travel speeds and driver behavior in terms of lane changing decisions and
“following too closely” appears to be the predominant factor in this section based on
team discussions and observations. While the cross-median occurrence is low in this
section, there is a high frequency of median related crashes. A risk rating of ‘D’ was
assigned to this factor.
MS Transportation Systems, Inc.
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Route I-495 Littleton Road Safety Audit
One item identified as contributing to a higher risk to safety was the extent of guardrail
provided in the area of the Route 2 overpass. The sections of rail do not appear to
extend far enough to adequately cover areas where the roadside slope is steeper than
6:1. A risk rating of ‘D’ was assigned to this factor primarily due to the potential severity
of the crash that is possible if an entry occurred in areas of steep slope. Other factors
noted include the narrow width of the inside shoulder and the lack of a rumble strip. The
ongoing rehabilitation project may ultimately address these items but confirmation is
needed.
The final two areas relate to markings and guidance through the acceleration and
deceleration lanes as well as indicating the location of the median. In general, there is a
low level of markings provided. A reason for this low level treatment may be due to
minimal shoulder width carried through the interchange. The section is also under
rehabilitation at the present time and final markings may not have been installed yet.
This could be checked in greater detail prior to future installation or maintenance actions.
Once the issues were identified and ratings assigned, suggested actions intended to
reduce the number of and consequences resulting from median related crashes and
other types of crashes as well were evaluated. The following paragraphs include a
discussion pertaining to the issues and the potential actions to consider for implement.
Given that this RSA is focused on cross-median events, the initial action evaluated was
the potential installation of a median barrier.
•
Consideration of a Median Barrier
One of the more significant actions that could be considered is to install median barriers
in the current “open” areas. Although the RSA team concluded that the open median
section did not pose a high risk at this time, the section was evaluated in terms of the
median barrier warrants. 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.
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
MS Transportation Systems, Inc.
 History of cross-median crashes
 High risk of catastrophic event
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Route I-495 Littleton Road Safety Audit
These items have been reviewed relative to the I-495 section under study. Figure 6
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 92-95 feet and a volume of over 100,000
vehicles on an average day, the intersection of the two criteria falls to the right of the
chart where a barrier can be “optional”.
In addition to the chart and related warrant criteria, which is a guideline, further
consideration was given to the following:
ƒ
ƒ
A small proportion of the median entries (28) over the four (4) year crash
period was experienced.
The road geometry is adequate and results in generally a comfortable drive.
Consequently, based on the analysis of the data, the field drive-thru and discussion of
the conditions by the RSA team members, it was concluded that a median barrier is not
warranted on this section of I-495 at this time.
4
American Association of State Highway and Transportation Officials, Roadside Design Guide,
Washington, D.C., 2002, Chapter 6 Update 2006.
MS Transportation Systems, Inc.
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median width 95-100 feet
volume > 100,000 ADT
80
AVERAGE DAILY TRAFFIC
(thousands)
70
BARRIER
RECOMMENDED
60
BARRIER
CONSIDERED
50
40
30
BARRIER
OPTIONAL
20
10
0
0
10
20
30
40
50
60
70
MEDIAN WIDTH
(feet)
Analysis of Median Barrier Warrant
I-495 Road Safety Audit
Littleton, Massachusetts
MS Transportation Systems, Inc.
Framingham, Massachusetts
Figure 6
Route I-495 Littleton Road Safety Audit
Recommendations
As a result of the RSA analysis and team input and although it was concluded that a
median barrier not be installed at this time based on the history of cross-median
crashes. However, should the frequency of cross-median crashes increase, then the
barrier installation should be reconsidered. A set of recommendations have been
identified and are summarized in Table 7. In general, these actions are intended to
reduce the chance of cross-median crashes as well as reduce the number and severity
of all crashes of this section of I-495 in Littleton. 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)).
TABLE 7
SUMMARY OF RECOMMENDATIONS
Risk Factor
“Open” roadside slopes
>6:1 near Route 2
overpass
Open Median
Risk
Rating
D
C
Narrow inside shoulder
without rumble strip
Recommended
Action
ƒ
extend guardrail –
total of approx. 600
feet in length
Estimated
Cost
$30,000
ƒ
Short to
medium
term
NO BARRIER
PROPOSED AT THIS
TIME
n/a
n/a
ƒ Widen shoulder
ƒ Install rumble strip
n/a1
n/a1
ƒ Could be
addressed in
on-going
construction
– need to
confirm
C
1
2
Estimated
Timeframe
High travel speeds and
driver behavior
D
ƒ Increase
enforcement levels
TBD
ƒ short term
Short accel/decel lanes
marked
C
ƒ provide consistent
and more visible
markings
$6,0002
ƒ short term
Limited motorists
guidance of median
location
C
ƒ Install flexible
delineator posts
$3,000
ƒ short term
may be included in ongoing rehabilitation project
TBD – to be determined
example of modified marking plans depicted in Appendix may be able to be incorporated as part of future marking
maintenance operation.
One factor that was noted at the Route 2 interchange is that the roadside slope in the
vicinity of the overpass is fairly steep (i.e. >6:1 slope) and the guardrail that is in place
appears to end to soon. With lane changing activity high at this interchange, extending
the guardrail would reduce the possibility of median entry crashes in this area. Figure 7
illustrates the general area of the extended guardrail. The estimated cost is $30,000.
MS Transportation Systems, Inc.
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495
ROUTE 2 EB ON-RAMP
EXTEND
GUARDRAIL 200 FEET
495
ROUTE 2 WB ON-RAMP
EXTEND
GUARDRAIL 400 FEET
Proposed Guardrail Extensions in NB
Direction at Route 2 Interchange
I-495 Road Safety Audit
Littleton, Massachusetts
MS Transportation Systems, Inc.
NOT TO SCALE
Framingham, Massachusetts
FIGURE 7
Route I-495 Littleton Road Safety Audit
Although it was decided that a median barrier is not needed at this time within section, it
was recommended that improved delineation of the median be implemented via
reflectorized, flexible posts. In addition, it was recommended that the inside shoulder be
set wide enough to accommodate a rumble strip. Ideally, the inside shoulder would be a
minimum of four (4) feet in width. The ongoing construction project is expected to
address this issue and is also expected to incorporate the rumble strips.
It is suggested that improved markings be provided at the acceleration and deceleration
lanes including the gore areas. Consistent, high visibility markings such as these shown
in Figure 8 or in the Appendix should be considered. Maintaining the minimum outside
shoulder width allowed through the interchange may be an issue without widening and
could limit the extent of markings. This can be examined in more detail when scheduling
pavement marking maintenance activities. If the acceleration lanes are confirmed to be
deficient and cannot be corrected by simply modifying the markings, then YIELD signs
should be installed on the ramps.
Lastly, travel speeds and driver behavior has been cited and observed to be a problem
on I-495 where volumes exceed 110,000 ADT. Increased enforcement levels should be
funded and provided.
MS Transportation Systems, Inc.
Page 16
OPTION A
OPTION B
Broken lane
markings for
one-half of
full-width
deceleration
lane
Channelizing
lines
Broken lane
markings for
one-half of
full-width
deceleration
lane
Channelizing
lines
Parallel acceleration lane
Potential Pavement Markings On Ramp Merge Locations
I-495 Road Safety Audit
Littleton, Massachusetts
MS Transportation Systems, Inc.
NOT TO SCALE
Framingham, Massachusetts
FIGURE 8
Route I-495 Littleton Road Safety Audit
Appendix
•
•
•
•
•
•
MS Transportation Systems, Inc.
RSA Meeting Agenda
RSA Meeting Attendees
Median Crash Diagram
Crash Summary Data
Traffic Volume Data
Example of AccelerationDeceleration Lane Markings
Page 18
Road Safety Audit
Littleton – Interstate 495
Meeting Location: MassHighway District 3 Office
403 Belmont Street, Worcester
Tuesday, July 22, 2008
11:00 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!!
11:00 AM
Welcome and Introductions
11:15 AM
Introduction to Road Safety Audits and Cross Median Crashes
11:30 AM
Review of Site Specific Material
• Crash & Volume Summaries– provided in advance
• Existing Geometries and Conditions
• Video and Images
12:00 PM
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 July 22nd, participants are encouraged to drive
Interstate 495 in Littleton from exit 29 – exit 31 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 - June 22, 2008
MassHighway District 3 Offices, Worcester MA
Attendance List
Name
Agency/Dept.
Email
Bill Scully
MS Transportation Systems, Inc.
bscullyjr@mac.com
Kathryn Cook
MHD, Traffic Intern
kathryn.cook@mhd.state.ma.us
Christine Breen
MHD, Highway Design
christine.breen@mhd.state.ma.us
Edward Pomfred
MHD, Traffic Intern
edward.pomfred@mhd.state.ma.us
Timothy White
FHWA
timothy.white@fhwa.dot.gov
Bonnie Polin
MHD
bonnie.polin@state.ma.us
Lisa Schletzbaum
MHD, Safety Management Unit
lisa.schletzbaum@mhd.state.ma.us
Sgt. Eugene O'Neill
MSP
eugene.oneill@polistate.ma.us
Robert Babb
MHD, District 3
robert.babb@mhd.state.ma.us
Mark Johnson
MHD, District 3
mark.johnson@mhd.state.ma.us
Chris Hogan
MHD, District 3
Eric Nascimento
MHD, District 3
MS Transportation Systems, Inc.
eric.nascimento@mhd.state.ma.us
Interstate 495 Median Crashes
"
)
±
31
WESTFORD
26
Crash IDs
between 14-25
)
"
15
119
14
BR
UC
E
AR
RV
A
H
D
R
O
ST
RE
ET
"
)
30
AD
KI
NG
ST
E
RE
N
KI
G
ST
E
RE
T
Crash IDs
between 10-13
)
"
T
2A
GO
LD
LITTLETON
I
SM
TH
ST
9
E
RE
T
ET
TAYLOR ST RE
§
¦
¨
495
SH
W
29
Crash IDs
between 3-8
O
OD
Type of Median
Crash 2004-2007 *
A
UE
Cross Median,
Fatal Crash
Interstate
Median, Non-Fatal Crash
Principal Arterial
)
"
OW
WT
NE
2
Y
ELE
RO
OR
TAY L
AD
E
ST R E
BOXBOROUGH
Municipal Boundary
EE T
K
BU L
1
R
E
Major Roads
VE
N
Median, Property Damage Only
TR
RS
STE
FO
E
N
Legend
HA
R
"
)
2
AK
LA
O
NR
AD
* 2007 crash file has not yet been closed.
0
0.1
0.2
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MASSACHUSETTS HIGHWAY SAFETY DIVISION
CRASH SUMMARY
ROADWAY:
I-495
STUDY PERIOD:
NO.
CITY:
1/1/2004
CRASH NUMBER
CRASH DATE AND TIME
LOCATION:
LITTLETON
TO
4/12/2008
TRAVEL
LIGHT
WEATHER
ROAD
REASON FOR
VEHICLE
MEDIAN OR CROSS
BOXBOROUGH TO WESTFORD TOWN LINES
DRIVER CONTRIBUTING
CRASH
DIRECTION
CONDITION
CONDITION
SURFACE
RUNNING OFF ROAD LEFT
MOVEMENT
MEDIAN CRASHES
CAUSE
SEVERITY
1
2180577
10/5/2006 Thu 4:55 AM
NB
Dark - not lighted
Clear
Dry
Vehicle 1 fail to stay in lane, striking the guardrail and vehicle 3 behind struck vehicle 1. Vehicle 3 veer off into median
Travel Lane to Median
Median
Failure to keep in proper lane or running off road
Non-fatal injury
2
2130302
12/7/2006 Thu 3:30 PM
NB
Daylight
Clear
Dry
Vehicle was cut off and swerved into guardrail to avoid striking the other vehicle
Travel lane to median
Median
No Improper Driving
Property Damage Only
3
2014665
2/27/2006 Mon 8:40 AM
SB
Daylight
Clear
Dry
Vehicle tried to merge into traffic from on-ramp, then got struck in the rear end and spun into median
Travel Lane to Median
Median
Not Reported
Property damage only
4
1795779
2/8/2004 Sun 11:21 AM
SB
Daylight
Clear
Dry
Vehicle 1 was struck by Vehicle 2, cause vehicle 1 struck the guardrail on the right then bounces into the median
Travel Lane to Right side Guardrail to Median
Median
Failure to keep in proper lane or running off road
Non-fatal injury
5
2066598
5/6/2006 Sat 2:15 PM
NB
Daylight
Rain
Wet
Unknown
NB Travel Lane to Median to SB travel lane
Cross Median
Not Reported
Fatal injury
6
2209071
4/4/2007 Wed 5:10 PM
SB
Daylight
Snow
Snow
Vehicle drove into median for an unknown reason
Travel lane to median
Median
Not Reported
Property Damage Only
7
2114966
7/31/2006 Mon 4:42 AM
SB
Dawn
Clear
Dry
Vehicle 1 was cut-off by Vehicle 2, lost control of vehicle and spun into median
Travel Lane to Median
Median
No Improper Driving
Property damage only
8
2311814
4/12/2008
Sat 7:23 AM
NB
Daylight
Rain
Wet
Vehicle lost control trying to pass another vehicle
Travel lane to median
Median
Not Reported
Non-Fatal Injury
9
2266284
12/16/2007 Sun 7:30 PM
NB
Dark- Unknown roadway lighting
Snow
Ice
Vehicle was struck by another vehicle and spun into median
Travel lane to median
Median
Not Reported
Property Damage Only
10
2254334
5/13/2007 Sun 4:55 AM
NB
Dusk
Not Reported
Dry
Vehicle lost control, went off the road to the left then cut across all lanes, ending in a ditch on the right side of the road
Travel lane to median to right side of road
Median
Not Reported
Property Damage Only
11
2256448
10/24/2007 Wed 12:25 PM
SB
Daylight
Cloudy
Dry
Vehicle was trying to pass another vehicle, struck the vehicle and spun into the median
Travel lane to median
Median
Not Reported
Property Damage Only
12
2298137
3/12/2008 Wed 6:40 PM
NB
Daylight
Cloudy
Wet
Vehicle swerved to avoid another vehicle and ran into embankment
Travel lane to median
Median
Not Reported
Property Damage Only
13
2282413
1/22/2008 Tue 4:05 PM
NB
Daylight
Cloudy
Dry
Vehicle was struck by another vehicle and spun into median
Travel lane to median
Median
Not Reported
Property Damage Only
14
1796022
7/16/2004 Fri 12:00 AM
NB
Dark - not lighted
Clear
Dry
Vehicle was cut-off by unknown vehicle, lost control of vehicle
Travel Lane to Median
Median
Failure to keep in proper lane or running off road
Property damage only
15
2130156
11/13/2006 Mon 5:25 PM
NB
Dark - not lighted
Rain
Wet
Vehicle was speeding, lost control of vehicle and went into embankment
Travel Lane to Median
Median
Exceeded authorized speed limit
Non-fatal injury
16
2059957
6/19/2006 Mon 9:30 AM
SB
Daylight
Clear
Dry
Vehicle was cut-off by another vehicle, lost control of vehicle and spun into median
Travel Lane to Median
Median
No Improper Driving
Property damage only
17
2211377
4/19/2007 Thu 11:04 AM
SB
Daylight
Clear
Dry
Driver had a seizure, swerved into median and overcorrected back onto road, striking another vehicle and ending up on right side of road
Travel lane to median to right side of road
Median
Not Reported
Non-Fatal Injury
18
2256451
10/23/2007 Tue 11:20 AM
SB
Daylight
Clear
Dry
Vehicle was cut off and swerved into median, striking a tree
Travel lane to median
Median
Not Reported
Non-Fatal Injury
19
2237805
4/25/2007 Wed 6:26 AM
SB
Not Reported
Not Reported
Dry
Vehicle rolled over into median for an unknown reason
Travel lane to median
Median
Not Reported
Non-Fatal Injury
20
2238120
9/22/2007 Sat 2:37 PM
NB
Daylight
Clear
Dry
Vehicle rolled over into the median avoiding a truck
Travel lane to median
Median
Not Reported
Non-Fatal Injury
21
2238521
8/7/2007 Tue 4:30 AM
NB
Dark- not lighted
Fog, Smoke, Smog
Dry
Vehicle rolled over into the median avoiding a truck
Travel lane to median
Median
Not Reported
Non-Fatal Injury
22
2220312
6/11/2007 Mon 7:23 PM
NB
Daylight
Clear
Dry
Vehicle lost control for an unknown reason and rolled over in median
Travel lane to median
Median
Not Reported
Non-Fatal Injury
23
2178870
3/16/2007 Fri 3:20 PM
NB
Daylight
Snow
Snow
Vehicle swerved to avoid another vehicle which had stopped suddenly and lost control due to slippery road conditions
Travel lane to median
Median
Not Reported
Non-Fatal Injury
24
2220299
5/28/2007 Mon 1:07 AM
NB
Dark- not lighted
Clear
Dry
Vehicle lost control for an unknown reason and rolled over in median
Travel lane to median
Median
Not Reported
Non-Fatal Injury
25
2323440
3/24/2008 Mon 5:32 PM
NB
Daylight
Clear
Dry
Vehicle swerved attempting to avoid another vehicle, struck the other vehicle and went into embankment
Travel lane to median
Median
Not Reported
Property Damage Only
26
2050445
3/27/2006 Mon 5:40 AM
SB
Dawn
Clear
Dry
Lost Control of the Vehicle and skidded onto the median
Travel Lane to Median
Median
Driving too fast for conditions
Property damage only
27*
2217556
8/7/2007 Tue 9:43 PM
NB
Dark- lighted roadway
Clear
Dry
Vehicle rolled over into the median avoiding a truck
Travel lane to median
Median
Not Reported
Non-Fatal Injury
28*
2306825
3/28/2008 Fri 6:10 AM
SB
Dawn
Sleet, hail (freezing rain or drizzle)
Snow
Vehicle lost control due to slippery road conditions and hit guardrail, entered traffic again and was struck by another vehicle
Travel lane to left side guardrail to travel lane
Median
Not Reported
Non-Fatal Injury
* Crash could not be geocoded based on reported location information
TOTAL NO.
28
100%
CLEAR
15
54%
CLOUDY
3
11%
WEATHER CONDITION
FOG, SMOKE, SMOG
RAIN
1
3
4%
11%
SNOW
2
7%
SLEET, HAIL
1
4%
NO IMPROPER DRIVING
3
11%
DUSK
CRASH SEVERITY
TYPE OF CRASH
NOT REPORTED
2
7%
DRIVER CONTRIBUTING CAUSE
PROPERTY DAMAGE
ONLY
13
46%
NON-FATAL INJURY
14
50%
FATAL INJURY
1
4%
NOT REPORTED
20
71%
FAILURE TO KEEP IN
PROPER LANE OR RUNNING
OFF ROAD
3
11%
DAYLIGHT
DARK- NOT LIGHTED
DARK- LIGHTED
LIGHT CONDITION
DARK- LIGHTING
UNKNOWN
DAWN
EXCEEDING
AUTHORIZED SPEED
LIMIT
1
4%
NOT REPORTED
16
5
1
1
3
1
1
57%
18%
4%
4%
11%
4%
4%
2007 and 2008 CRASH INFORMATION IS NOT COMPLETE
CRASH SUMMARY IS BASED ON ELECTRONIC CRASH REPORTS WITH POLICE NARRATIVES
DRIVING TOO FAST FOR CONDITIONS
1
4%
MEDIAN
27
96%
CROSS MEDIAN
1
4%
I-495, N. of RT-2 4/12/2006
Northbound Southbound
Direction
Direction
Start time
12:00 AM
452
525
1:00 AM
383
426
2:00 AM
531
434
3:00 AM
743
419
4:00 AM
1,440
614
5:00 AM
3,149
1,575
6:00 AM
4,634
3,493
7:00 AM
4,658
5,131
8:00 AM
3,120
5,082
9:00 AM
2,695
3,760
10:00 AM
2,644
2,826
11:00 AM
2,687
2,900
12:00 PM
2,801
2,785
1:00 PM
3,212
2,956
2:00 PM
4,083
3,474
3:00 PM
4,581
3,952
4:00 PM
4,852
4,449
5:00 PM
3,462
4,806
6:00 PM
2,117
2,907
7:00 PM
1,559
2,612
8:00 PM
1,290
1,741
9:00 PM
1,091
1,503
10:00 PM
848
1,106
11:00 PM
608
759
Daily Total
57,640
TOTAL
977
809
965
1,162
2,054
4,724
8,127
9,789
8,202
6,455
5,470
5,587
5,586
6,168
7,557
8,533
9,301
8,268
5,024
4,171
3,031
2,594
1,954
1,367
60,235
117,875
6,000
Northbound Direction
Southbound Direction
5,000
4,000
3,000
2,000
1,000
PM
:0
0
PM
10
PM
8:
00
PM
6:
00
PM
Time of Day
4:
00
PM
2:
00
:0
0
AM
12
:0
0
AM
10
AM
8:
00
AM
6:
00
AM
4:
00
2:
00
:0
0
AM
0
12
Hourly Volume (Number of Vehicles)
Directional Traffic Volumes along I-495, North of Route 2, Littleton
Wednesday, April 12, 2006
I-495, S. of RT-2 6/27/2007
Northbound Southbound
Direction
Direction
Start time
12:00 AM
540
513
1:00 AM
457
395
2:00 AM
474
322
3:00 AM
572
384
4:00 AM
762
529
5:00 AM
1,422
1,314
6:00 AM
2,757
2,816
7:00 AM
3,983
4,408
8:00 AM
4,192
4,157
9:00 AM
3,625
3,427
10:00 AM
3,250
2,730
11:00 AM
2,850
2,709
12:00 PM
2,808
2,904
1:00 PM
2,860
2,682
2:00 PM
3,258
3,157
3:00 PM
3,925
3,518
4:00 PM
4,227
3,986
5:00 PM
4,242
3,897
6:00 PM
3,572
3,367
7:00 PM
2,147
1,831
8:00 PM
1,669
1,705
9:00 PM
1,413
1,349
10:00 PM
1,120
934
11:00 PM
1,067
773
Daily Total
57,192
TOTAL
1,053
852
796
956
1,291
2,736
5,573
8,391
8,349
7,052
5,980
5,559
5,712
5,542
6,415
7,443
8,213
8,139
6,939
3,978
3,374
2,762
2,054
1,840
53,807
110,999
5,000
Northbound Direction
Southbound Direction
4,500
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
PM
:0
0
PM
10
PM
8:
00
PM
6:
00
PM
Time of Day
4:
00
PM
2:
00
:0
0
AM
12
:0
0
AM
10
AM
8:
00
AM
6:
00
AM
4:
00
2:
00
:0
0
AM
0
12
Hourly Volume (Number of Vehicles)
Directional Traffic Volumes along I-495, South of Route 2, Littleton
Wednesday, June 27, 2007
Examples of Channelizing Line
Applications for Exit Ramp Markings
a-Parallel
deceleration lane
b-Tapered
deceleration lane
Neutral
area
Optional
chevron
markings
Channelizing
lines
Theoretical gore
point
Channelizing
lines
Broken lane
markings for onehalf of f ull-width
deceleration lane
Optional
dotted
extension of
lane line
Legend
Direction of travel
Source: Manual on Uniform Traffic Control Devices
Potential Pavement Markings Off Ramp Diverge Locations
NOT TO SCALE
MS Transportation Systems, Inc.
Framingham, Massachusetts
Examples of Channelizing Line
Applications for Exit Ramp Markings
c-Auxiliary lane, such as at cloverleaf
interchange
Neutral area
Optional chevron
markings
Theoretical gore
point
Broken lane line markings for full
length of acceleration/deceleration
lane
Channelizing
lines
Legend
Direction of travel
Source: Manual on Uniform Traffic Control Devices
Potential Pavement Markings On/Off Ramp Merge Locations
NOT TO SCALE
MS Transportation Systems, Inc.
Framingham, Massachusetts