ROAD SAFETY AUDIT
Interchange of Routes 9 and 20
Town of Northborough
November, 2012
Prepared for:
Massachusetts Department of Transportation
Prepared by:
Howard/Stein-Hudson Associates
38 Chauncy Street
Boston, MA 02111
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Table of Contents Background ................................................................................................................................. 2
Project Data................................................................................................................................. 4
Project Location Description ..................................................................................................... 4
Road Safety Audit Observations ...............................................................................................9
Ramp #1. Route 20 on-ramp to Route 9 westbound ......................................................... 10
Ramp #2. Route 9 westbound off-ramp to Route 20 westbound....................................... 13
Ramp #3. Route 9 westbound off-ramp to Route 20 eastbound ........................................ 15
Ramp #4. Route 9 eastbound off-ramp to Route 20 eastbound......................................... 17
Ramp #5. Route 20 on-ramp to Route 9 eastbound........................................................... 19
Ramp #6. Route 9 eastbound off-ramp to Route 20 westbound........................................ 22
Area-Wide Observations ................................................................................................................... 23
Potential Safety Enhancements ...............................................................................................26
List of Appendices
Appendix A. Appendix B. Appendix C. Appendix D. RSA Meeting Agenda RSA Audit Team Contact List Detailed Crash Data Additional Information List of Figures
Figure 1. Figure 2. Locus Map.............................................................................................................................. 3
Interchange of Routes 9 and 20 .............................................................................................. 7
List of Tables
Table 1. Table 2. Participating Audit Team Members ....................................................................................... 4
Summary of Potential Safety Enhancements ....................................................................... 27
Page 1
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Background
The interchange of Routes 9 and 20 falls within the Top 5% of High Crash Locations within the Central
Massachusetts Regional Planning Commission (CMRPC) area. During the Road Safety Audit (RSA), the
team focused on safety issues at each of the six ramps within the interchange as well as general safety
issues along Routes 9 and 20 in the vicinity of the interchange. The study area is illustrated in Figure 1.
From October 1, 2011 to August 28, 2012, 110 crashes were reported at the interchange, plus 67
additional incidents involving less than $1,000 worth of damage; this time period is following the
completion of the recent ramp reconfiguration at the interchange, which was completed around October
2011. A review of historic crash data at the interchange reveals a substantial increase in crashes from just
8 crashes in 2009, and 15 crashes in 2010, to approximately 68 crashes in 2011. The total number of
crashes from 2011 to 2012 nearly doubled.
According to team members, the increase in crashes at the interchange is directly related to the increase in
traffic volume associated with the significant increase in new residential and commercial development in
the area. Most notably, a development of approximately 175-acres consisting of approximately 600,000
square feet of retail called Northborough Crossing, and approximately 400 units of housing called Avalon
Northborough, is located approximately 0.25 miles from the interchange and was completed in October
2011. As part of mitigation to help offset the new traffic these developments would bring, the
interchange, which had been a traditional cloverleaf, was reconfigured in an effort to reduce weaving
along Route 9. The Route 20 eastbound on-ramp to Route 9 westbound was removed and replaced with a
signalized left-turn lane on Route 20 eastbound, which provides access to the existing Route 20
westbound on-ramp to Route 9 westbound. The Route 20 westbound on-ramp to Route 9 eastbound was
also removed and replaced with a signalized left-turn lane on Route 20 westbound, which connects to the
existing Route 20 eastbound on-ramp to Route 9 eastbound. MassDOT also recently resurfaced Route 20
(MassDOT Project #606151), which was completed in October 2012.
MassDOT has determined that the Town of Northborough would be eligible to receive Highway Safety
Improvement Program (HSIP) funding for construction/implementation of safety enhancements at the
interchange if a Road Safety Audit (RSA) were conducted and the proposed design incorporates the
safety improvements identified in the RSA.
In general, the RSA is intended to identify potential safety improvements that can be evaluated and
included as part of future design efforts for reconstruction. The short-term, low-cost potential
improvements could be considered by the responsible agency for implementation prior to reconstruction,
as appropriate.
Page 2
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Figure 1.
Locus Map
RSA Study Area
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Source: Google Maps
Howard/Stein-Hudson Associates, Inc.
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Project Data
The audit team conducted an RSA at the interchange of Routes 9 and 20 on Wednesday, November 7,
2012. The RSA agenda appears in Appendix A. Table 1 lists the audit team members and their
affiliations. Appendix B provides contact information for all team members.
Prior to the RSA, in order to begin assessing possible safety issues, the team reviewed collision diagrams
and crash detail summaries for the interchange, based on crash records supplied by the Northborough
Police Department. Appendix C provides the detailed crash data for the study area. Speed regulation
data is provided in Appendix D.
Table 1. Participating Audit Team Members
Audit Team Member
Promise Otaluka
Alolade Campbell
Joe Frawley
Bill Lyver
Chief Mark Leahy
Kevin Krasnecky
Sujatha Mohanakrishnan
Dan Daniska
Dan Mason
David M. Durgin
John W. Coderre
Silpa Munukutla
Corey O’Connor
Lisa Schletzbaum
Joe SanClemente
Mike Tremblay
Agency/Affiliation
Federal Highway Administration
MassDOT District 3 Traffic
MassDOT District 3 Traffic
Northborough Police
Northborough Police
Central Massachusetts Regional Planning Commission (CMRPC)
Central Massachusetts Regional Planning Commission (CMRPC)
Central Massachusetts Regional Planning Commission (CMRPC)
Northborough DPW
Northborough Fire/EMS
Northborough Town Administrator
MassDOT
MassDOT Highway Division
MassDOT Highway Division
Howard/Stein-Hudson (HSH)
Howard/Stein-Hudson (HSH)
Project Location Description
The RSA focused on safety issues at the interchange of Routes 9 and 20 in the town of Northborough.
Route 9 is a major state highway that provides connections to I-495, I-90, and I-290. Route 20 provides
access to downtown Northborough as well as major retail and local residential uses. The interchange is
located just south of a large newly-completed retail development called Northborough Crossing, which
contains a BJ’s Wholesale Club, Dicks Sporting Goods, Wegman’s Wine, Liquor and Beer Shop, Kohls,
and other retail locations, which can be accessed from Route 20. Also north of the interchange on Route
20 is a newly completed residential development called Avalon Northborough, which consists of about
400 residential units. Econo Lodge Inn and Suites and JJ’s Sports Bar and Grill are located adjacent to
the interchange in the southwest quadrant, and are provided with access on Route 9 eastbound and on
Route 20. A large shopping center, containing a Sears Outlet, Christmas Tree Shops, and other
Page 4
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
establishments, lies approximately 0.30 miles west of the interchange, and can be accessed from Route 9
eastbound and from Route 20.
The interchange is formed by the junction of the following roadways, which are categorized according to
MassDOT Office of Transportation Planning functional classifications:
Route 9 (Belmont Street) is classified as an urban principal arterial and falls under MassDOT
jurisdiction. Route 9 generally runs in an east-west direction, originating at Copley Square in Boston as
Huntington Avenue in the east, and terminating in Pittsfield as East Street to the west. Within the study
area, Route 9 is generally two lanes in each direction and divided by a concrete barrier. The speed limit is
posted at 50 miles per hour (mph) within the study area.
Route 20 (Southwest Cutoff) is classified as an urban principal arterial and falls under MassDOT
jurisdiction. Route 20 in Massachusetts generally runs in an east-west direction, originating at Kenmore
Square in Boston as Commonwealth Avenue to the east, and runs to the New York state line in Hancock.
Within the study area, Route 20 runs in a north-south direction; with eastbound traffic traveling in a
northerly direction and westbound traffic traveling in a southerly direction. Within the audit study area,
Route 20 westbound opens up to two through lanes beginning at Shops Way. These two westbound
through lanes continue past the study area. Directly south of the audit study area, Route 20 carries two
eastbound lanes, with one lane splitting off to the Route 9 eastbound ramp. Single lane eastbound traffic
continues through north of the study area. The speed limit is posted at 45 mph near the study area.
The RSA team focused on the following six ramp locations within the interchange (see Figure 2):
1.
2.
3.
4.
5.
6.
Route 20 on-ramp to Route 9 westbound (located on the northwest quadrant of the interchange);
Route 9 westbound off-ramp to Route 20 westbound (northwest quadrant);
Route 9 westbound off-ramp to Route 20 eastbound (northeast quadrant);
Route 9 eastbound off-ramp to Route 20 eastbound (southeast quadrant);
Route 20 on-ramp to Route 9 eastbound (southeast quadrant); and
Route 9 eastbound off-ramp to Route 20 westbound (southwest quadrant).
The RSA team also discussed general safety issues within and around the interchange. The six ramp
locations are described below.
Ramp #1: Route 20 on-ramp to Route 9 westbound (northwest quadrant) is a one-lane ramp that begins
on Route 20, approximately 650 feet north of the Route 9 bridge over Route 20, and connects to Route 9
westbound approximately 700 feet west of the bridge. The ramp provides access to Route 9 westbound
from both directions on Route 20. Vehicles traveling on Route 20 eastbound are provided with a
dedicated left-turn lane and signal to access the ramp. Vehicles traveling on Route 20 westbound may
travel freely onto the ramp. The on-ramp intersects Route 9 westbound at an acute angle and operates
under stop sign control. An acceleration lane onto Route 9 is not provided.
Ramp #2: Route 9 westbound off-ramp to Route 20 westbound (northwest quadrant) is a one-lane ramp
that begins on Route 9 westbound, just west of the Route 9 bridge over Route 20, and connects to Route
Page 5
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
20 westbound, just north of the bridge. Vehicles traveling on Route 9 westbound may travel freely onto
the ramp. The ramp intersects Route 20 at an acute angle and operates under stop sign control.
Page 6
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Figure 2. Interchange of Route
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Source: Google Maps
Howard/Stein-Hudson Associates, Inc.
X
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Ramp #3: Route 9 westbound off-ramp to Route 20 eastbound (northeast quadrant) is a one-lane ramp
that begins on Route 9 westbound, east of the Route 9 bridge over Route 20, and connects to Route 20
eastbound approximately 650 feet north of Route 9. The ramp intersects Route 20 directly across from the
Route 20 on-ramp to Route 9 westbound. Vehicles traveling westbound on Route 9 may travel freely onto
the ramp; a deceleration lane of approximately 300 feet is provided. The ramp intersects Route 20 at an
acute angle and is controlled by a signal, where right turns on red are permitted.
Ramp #4: Route 9 eastbound off-ramp to Route 20 eastbound (southeast quadrant) is a one-lane ramp
that begins on Route 9 eastbound, just east of the bridge over Route 20, and connects to Route 20
eastbound just south of the bridge. Vehicles traveling on Route 9 eastbound may freely enter the ramp;
however, there is no deceleration lane approaching the ramp. The ramp intersects with Route 20 at
eastbound at an acute angle and is stop-controlled.
Ramp #5: Route 20 on-ramp to Route 9 eastbound (southeast quadrant) is a straight ramp that begins
on Route 20, approximately 900 feet south of the Route 9 bridge over Route 20, and connects to Route 9
eastbound, approximately 700 feet east of the bridge. Vehicles traveling on Route 20 eastbound may
freely enter the ramp. Vehicles traveling westbound on Route 20 access the ramp using a signalized leftturn lane.
Ramp #6: Route 9 eastbound off-ramp to Route 20 westbound (southwest quadrant) is a one-lane ramp
that begins on Route 9 eastbound, approximately 700 feet west of the Route 9 bridge over Route 20, and
connects to Route 20 westbound, approximately 550 feet south of the interchange. Vehicles entering the
ramp from Route 9 eastbound may freely enter the ramp; a deceleration lane is provided in advance of the
off-ramp that also accommodates vehicles accessing the retail uses west of the ramp. The ramp intersects
Route 20 at an acute angle and operates under stop-control.
Page 8
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Road Safety Audit Observations
Based on field observations on Wednesday, November 7, the RSA team determined that the interchange
of Routes 9 and Route 20 has the following issues that affect safety:







Constrained ramp geometry;
Motorist confusion;
Confusing and/or hard to see signage;
Queuing and driver frustration;
Limited visibility of signal indications;
Lack of acceleration/deceleration lanes; and
High travel speeds.
The following sections describe in more detail the safety issues and potential enhancements determined
during the RSA. Several of these issues require further study and engineering judgment to determine the
feasibility of implementing enhancements to address them.
Page 9
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Ramp #1. Route 20 on-ramp to Route 9 westbound
Observations:
Of the 110 crashes that were reported within the interchange between October 1, 2011 and
August 28, 2012, 65 (59%) occurred on the Route 20 ramp to Route 9 westbound.
Of the 65 crashes, 59 occurred at the end of the ramp at its intersection with Route 9, including 58
(98%) rear-end crashes and one (2%) single-vehicle crash involving a motorist who swerved in
order to avoid a rear-end collision but struck a stop sign instead. These crashes were generally a
result of driver inattention, following too closely, or other improper actions.
The remaining six of the 65 crashes at this ramp (9%), occurred at the entrance to the on-ramp,
including three angle-type crashes (50%), two single-vehicle crashes (33%), and one rear-end
crash (17%). One of the two single-vehicle crashes involved a dump truck that forgot to lower
the back bed and struck the overhead mast arm, knocking it down, and eliminating the video
detection at the signal. The other single-vehicle crash involved a motorist who struck a deer just
north of the entrance to the ramp.
The following details the observations with respect to ramp geometry, travel speeds, and signal
indications:
Ramp Geometry and Travel Speeds
The Route 20 on-ramp intersects Route 9 westbound at an acute angle and operates under stop control; however, no acceleration lane onto Route 9 westbound is provided. Meanwhile, motorists traveling along Route 9 westbound generally travel well in excess of the posted speed limit of 50 mph, making it extremely difficult for motorists to accelerate from a complete stop to 50 mph or greater in order to merge with Route 9 traffic. As a result motorists often “roll through” the
stop sign so that they can more easily get up
The Route 20 on-ramp to Route 9 westbound
to speed with traffic on Route 9. RSA team
is stop controlled, making it difficult for
motorists to merge onto Route 9 westbound.
members commented that the word “STOP”
was recently painted at the stop bar, which
seems to have reduced the number of
motorists that roll through; however, those familiar with the intersection still typically roll
through.
Since the ramp intersects Route 9 at an acute angle, motorists either at or approaching the stop
line must then look over their left shoulder to see on-coming traffic to judge if they have an
Page 10
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
adequate gap in the passing traffic stream; however, the sight line of oncoming traffic on Route 9
is partially limited by the presence of a group of trees and other vegetation just east of the ramp.
RSA team members commented that motorists often begin looking towards oncoming traffic as
soon as possible to begin looking for an acceptable gap in traffic, and do not anticipate stopped
vehicles ahead of them on the ramp.
Signage
The ramp’s approach to Route 9 westbound operates under stop-control and is provided with two
stop signs, one on each side of the ramp. An RSA team member noted that the stop sign on lefthand side of the ramp is posted mounted on the same post as a guide sign for Route 9 westbound.
Another team member commented that this guide sign seemed unnecessary.
The District recently installed Stop Ahead
(W3-1) warning signs in September, 2012.
Thus, before these signs were installed,
crashes may have occurred because
motorists unfamiliar with the area may not
have expected that they needed to stop
and/or that there may have been queuing as
they approached Route 9.
Signal Indications
Of the six crashes reported at the entrance
to the ramp at Route 20, one involved a
dump truck traveling along Route 20
westbound that forgot to lower its bed and
struck the overhead mast arm, knocking it
down, and eliminated the video detection at
the signal. As a result of this crash, a
temporary signal indication and post were
placed on the southern corner of the Route
20 on-ramp to Route 9 west, adjacent to
Route 20 for Route 20 westbound for Route
20 westbound; however, video detection is
currently not provided and the signal is
operating on maximum recall settings.
Visibility of the temporary signal for Route 20
westbound is blocked by signage.
Three of the crashes were angle-type
crashes involving vehicles turning left from
Route 20 eastbound onto the on-ramp with vehicles traveling on Route 20 westbound. At least
two of the three angle-type crashes were attributed to a motorist running a red light. RSA team
members commented that these crashes were likely the result of the video detection not working
Page 11
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
as it was reported that some motorists had become confused/frustrated with the lack of detection
and were running red lights.
RSA team members noted that the temporary signal indication for Route 20 westbound, on a
nonstandard pole, was blocked from view by guide and warning signage as of the date of the
RSA. Limited visibility of the Route 20 westbound signal indication may have contributed to the
rear-end crash involving two westbound vehicles. A new mast arm was installed in November,
2012, shortly after the RSA was completed; however, a team member noted that detection still is
not functioning properly.
Potential Enhancements:
1. Consider the appropriateness of replacing existing stop signs (R1-1) at the end of the
ramp with oversized signage and add retroreflective tape on sign posts to improve their
visibility.
2. Consider the appropriateness of providing speed advisory signage (W13-3) at the
entrance to the ramp to reduce speeds on the ramp.
3. Consider the appropriateness of trimming, or removing, the group of trees located just
east of the ramp approach so that vehicles traveling on the ramp can see oncoming traffic
traveling along Route 9 westbound.
4. Remove guide sign for Route 9 located at the end of the ramp on the left-hand side and
relocate the existing stop sign to a separate post.
5. Consider the feasibility of adding an acceleration lane on Route 9 westbound to facilitate
a safe merge from the ramp; replace signage as appropriate.
6. Verify that video detection gets replaced and functions properly.
Page 12
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Ramp #2. Route 9 westbound off-ramp to Route 20 westbound
Observations:
Of the 110 crashes reported at the interchange, 14 (or 13%) occurred along the Route 9
westbound off-ramp to Route 20 westbound. All of the crashes were rear-end crashes and
occurred at the ramp’s intersection with Route 20 westbound. Three of the crashes resulted in
personal injury.
The following details the observations with respect to ramp geometry and signage.
Ramp Geometry
At the beginning of the ramp on Route 9, no deceleration lane is currently provided. Thus,
motorists entering the ramp must decelerate from 50 mph or more within the travel lane onto a
ramp with a tight radius. Team members observed that vehicles, that were continuing westbound
on Route 9, generally drive aggressively as motorists attempt to slow down to turn onto the ramp.
Once on the ramp, the small radius makes it difficult for
motorists to slow down and to perceive and react to the
approaching queue stopped at the stop line at Route 20.
Furthermore, sight lines on the ramp are limited due to
the presence of trees and other vegetation on the inside
of the curve, which makes it difficult for motorists to see
cars queued at the stop line. One of the reported crashes
at this location occurred when a motorist noticed a fastmoving car approaching from behind – the motorist then
attempted to pull away, but hit the car ahead in the
queue. Team members commented that the queue often
backs up to Route 9.
The Route 9 westbound off-ramp
intersects Route 20 westbound at
an acute angle.
At the end of the ramp, the ramp approach intersects Route 20 westbound at an acute angle,
making it difficult for motorists to see oncoming traffic over their left shoulder, while watching
out for the vehicle in front of them. One of the reported crashes occurred when the first vehicle
stopped at the stop line moved forward, then stopped quickly, causing a rear-end collision with a
second vehicle.
Signage
Two stop signs are currently located at the end of the ramp at its intersection with Route 20
westbound. During field observations, it was noted that one of these stop signs was tilted as if it
had been hit. RSA team members also noted that there are no ramp speed advisory or chevron
signs on the ramp to warn motorists. The District recently installed Stop Ahead (W3-1) warning
signage in September, 2012.
Page 13
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Potential Enhancements:
1. Consider the feasibility and safety benefits of softening the radius of the off-ramp and
creating a T-intersection at the end of the off-ramp at Route 20 westbound to improve
sight lines.
2. Consider the appropriateness of adding signalization to the ramp at its intersection with
Route 20 if a signal is warranted at the location, while considering impacts to the ramp’s
capacity. Also consider queue detection to prevent vehicle backup onto Route 9.
3. Maintain, and/or remove, trees/vegetation on the inside radius of the ramp so that
approaching vehicles can see vehicles queuing at the ramp’s stop line at Route 20.
4. Consider providing additional ramp speed advisory signage (W13-3), and/or chevrons, at
the entrance to the ramp to warn motorists to reduce speeds on the ramp.
5. Consider replacing existing advanced “Stop Ahead” (W3-1) sign along the ramp with one
equipped with flashing lights to improve visibility, to further encourage caution when
approaching Route 20.
Page 14
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Ramp #3. Route 9 westbound off-ramp to Route 20 eastbound
Observations:
Six (5%) of the 110 reported crashes that occurred at the interchange of Routes 9 and 20 occurred
at the Route 9 westbound off-ramp to Route 20 eastbound. All of these crashes were rear-end
crashes and occurred at the ramp’s intersection with Route 20 eastbound; one crash resulted in
personal injury.
The following details the observations with respect to ramp geometry, signal indications, and
signage.
Ramp Geometry
The horizontal and vertical curvature of the ramp
combined with the tree line on the inside of the curve limits sight lines for motorists approaching the back of the queue stopped at the end of the ramp. The downhill slope on the ramp also encourages faster speeds as vehicle approach the stop line. The ramp then intersects Route 20 eastbound at an
acute angle and operates under signal control, where
right turns on red are permitted. An RSA team
member commented that site lines west of the stop line
Vehicles queued on Route 9
along Route 20 are limited due to the presence of
westbound off-ramp at Route 20
overgrown vegetation on the south side of the
tb
d
roadway. The acute intersection angle, combined with
the sight distance limitations, makes it difficult for motorists to see oncoming traffic when
attempting to turn right on red.
Signal Indications
At the intersection with Route 20 eastbound, the ramp is provided with two overhead signal
indications on a mast arm. Right-turns on red are permitted; however, RSA team members noted
that vehicles often stop past the stop line in order to see oncoming traffic on Route 20 due to the
sight distance limitations west of the ramp. As a result these motorists have difficultly seeing the
overhead indications. One of the reported crashes involved a vehicle that was delayed at a green
light and was rear-ended by a motorist who assumed that the vehicle had passed through the
signal.
Signage
RSA team members noted that there are no speed advisory signs on the ramp to warn motorists.
Page 15
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Potential Enhancements:
1. Consider the appropriateness and safety benefits of providing a supplemental signal
indication at the end of the ramp to improve visibility of the signal indications for
vehicles either stopped at, or approaching, the stop line.
2. Consider the feasibility of repositioning or reorienting existing signal heads so that they
are more visible to motorists at or ahead of the stop line.
3. Consider providing additional ramp speed advisory signage (W13-3) at the entrance to
the ramp to reduce speeds on the ramp.
4. Consider the appropriateness of providing advanced “Signal Ahead” (W3-3) signage on
the ramp.
5. Consider trimming overgrown vegetation along the south side of Route 20 to improve
sightlines for vehicles attempting to make a right turn on red at the ramp stop line.
6. Consider trimming overgrown vegetation along the north side of the ramp to improve the
visibility of the signal indications and the back of the traffic queue.
Page 16
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Ramp #4. Route 9 eastbound off-ramp to Route 20 eastbound
Observations:
Five (5%) of the 110 crashes that occurred at the interchange of Routes 9 and 20 between October
1, 2011 and August 28, 2012 occurred at the Route 9 eastbound off-ramp to Route 20 eastbound.
All of these crashes were rear-end crashes and occurred at the end of the ramp at its intersection
with Route 20 eastbound.
At the beginning of the ramp, no deceleration lane is provided along Route 9 eastbound. Thus, vehicles entering the ramp must slow down from 50 mph or more on the ramp, which has a tight turning
radius. The ramp’s tight radius and downhill slope combined with vegetation on the inside of the radius makes it difficult for vehicles on the ramp to see oncoming traffic on Route 20. Furthermore, the ramp is also on a downgrade towards Route 20, potentially making it difficult to stop on a slippery
road surface. According to the crash data, two of the five rear-end crashes occurred on wet pavement.
There is no acceleration lane on Route
20 eastbound due to a bridge abutment.
The ramp then intersects Route 20 eastbound at an acute angle and operates under stop sign
control; no acceleration lane for vehicles to safely merge onto Route 20. Once at the stop line, or
as they approach, motorists must then look over their left shoulder in order to find an acceptable
gap in traffic, all while watching for vehicles in front of them in the queue. During the field visit,
team members observed vehicle queues that extended nearly up to Route 9 and that some
motorists did not stop at the stop sign. Queuing conditions on the ramp may contribute to driver
inattention and the occurrence of rear-end crashes
at this approach; four of the five rear-end crashes
reported were attributed to driver inattention.
Meanwhile on Route 20 eastbound, there is only
one travel lane in the vicinity of the ramp, due to a Route 9 bridge abutment. Team members commented that the heavy traffic conditions in one travel lane combined with the lack of an acceleration lane makes it difficult for motorists waiting at the stop line to find an acceptable gap when turning onto Route 20.
Long queues entering Route 20 eastbound from Route 9 eastbound.
Page 17
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Potential Enhancements:
1. Consider the feasibility of softening the radius of the off-ramp to create a T-intersection
between the Route 9 eastbound off-ramp to Route 20 eastbound, which would make it
easier for vehicles to merge onto Route 20 and make it easier for queued vehicles to see
to approaching vehicles.
2. Consider providing additional ramp speed advisory signage (W13-3) and chevrons along
the ramp to warn motorist and reduce speeds on the ramp.
3. Consider the appropriateness of providing advanced “Stop Ahead” (W3-1) signage on the
ramp.
4. As part of long-term planning efforts with bridge reconstruction, consider adding an
acceleration lane along Route 20 eastbound.
Page 18
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Ramp #5. Route 20 on-ramp to Route 9 eastbound
Observations:
Nine crashes were reported on the Route 20 on-ramp to Route 9 eastbound between October 1, 2011 and August 28, 2012. Eight (89%) of these crashes were rear-end crashes, and one (11%) was a single-vehicle crash. Vehicles traveling along Route 20 eastbound are provided with a dedicated lane leading to the on-ramp. As part of the recent resurfacing of Route 20, new guide signage and pavement markings are provided along Route 20
eastbound, including pavement markings Route 20 eastbound traffic may enter the onwithin the on-ramp indicating “TO 9 EAST”. ramp to Route 9 eastbound without slowing
Vehicles entering the ramp from Route 20 down.
westbound are provided with a dedicated, signalized left-turn lane that accesses a separate ramp that intersects with the Route 20 eastbound on-ramp to Route 9 eastbound. The Route 20 eastbound and westbound ramps are each provided with separate lanes, designated
by a dashed white lane line, for a short distance, before eventually merging into one lane.
However, team members noted that the markings may still be in a temporary condition, which
may add to confusion among motorists about how many lanes there are in the merge area. The
speed limit on Route 20 is 50 mph, and vehicles entering the ramp from Route 20 eastbound
generally do not slow as they are provided with an acceleration lane on Route 9. During the
audit, team member members noted that vehicles making the left-turn onto the ramp generally
stop if they see a vehicle approach on the ramp from Route 20 eastbound since they are typically
driving at a high rate of speed.
Of the nine crashes reported on the ramp between October 1, 2011 and August 28, 2012, four
involved rear-end crashes between vehicles entering the ramp from Route 20 westbound, two
involved rear-end crashes between two vehicles entering from Route 20 eastbound, and one
involved a rear-end crash where a vehicle entering from Route 20 westbound was rear-ended by a
vehicle entering from Route 20 eastbound. At least two of the rear-end crashes involving two
vehicles entering from Route 20 westbound occurred because one vehicle slowed or stopped
suddenly to yield to traffic entering from Route 20 eastbound. Both crashes involving two
vehicles entering from Route 20 eastbound involved vehicles slowing or stopping to yield to
vehicles entering from Route 20 westbound; one of these crashes resulted in personal injury.
Team members commented that the number of crashes during 2011/2012 at this ramp location
may be partially attributed to confusion before/during the recent resurfacing and may not reflect
the improvements to signage pavement markings.
Page 19
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Route 20 westbound currently has no signal control south of the Route 9 bridge, including the
Route 9 eastbound off-ramp to Route 20 westbound, which is not signal-controlled despite its
proximity to a traffic signal that controls entrance to the Route 20 on-ramp to Route 9 eastbound.
Lastly, a team member commented that Route 20 westbound is provided with a signalized leftturn lane, while the Route 20 westbound through lanes are uncontrolled movements; as such
motorists traveling through along Route 20 westbound may be confused by a red signal indication
intended for the left-turn lane. A team member noted that it may be confusing for motorists that
Route 9 eastbound ramp to Route 20 westbound is stop-controlled when it is in such close
proximity to a signalized intersection.
Page 20
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Potential Enhancements:
1. Consider the safety benefits re-striping the existing dashed white lane line to a solid white
lane line to reinforce that traffic from Route 20 eastbound and Route 20 westbound may
travel in two separate lanes for a short distance. Consider the use of recessed pavement
markings for increased visibility.
2. Consider the appropriateness and safety benefits of implementing geometric changes to
force a deliberate right-turn from Route 20 eastbound onto the ramp to decrease speeds
on the ramp if pavement marking improvements do not reduce the number of crashes on
the ramp.
3. Evaluate the intersection control for all approaches and consider modifications to reduce
potential driver confusion.
Page 21
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Ramp #6. Route 9 eastbound off-ramp to Route 20 westbound
Observations:
No crashes were reported on the Route 9 off-ramp
to Route 20 westbound; however, RSA team
members observed skid marks on the recently
resurfaced ramp just upstream of the stop line at Route 20. Since the ramp is stop-controlled, and sightlines appear to be adequate, the skid marks may indicate that motorists may be entering the ramp at a high rate of speed, and that travel speeds on the ramp may be high. Along Route 9 eastbound, a wide outside travel lane is provided of the off-ramp that appears wide enough to provide a separate deceleration line; however, clear pavement markings are not provided delineating the deceleration lane Skid marks were observed on the ramp,
which was recently resurfaced.
Potential Enhancements:
1. Consider the appropriateness of providing additional ramp speed advisory signage (W13-3)
and chevrons along the ramp to warn motorist and reduce speeds on the ramp.
2. Consider the feasibility of using pavement markings to delineate the deceleration lane to
clarify lane use for motorists.
Page 22
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Area-Wide Observations
Observations:
In addition to observations at the individual ramps, the RSA team also identified general safety
issues within and around the vicinity of the interchange.
The following details the observations with respect to drainage, lighting, signage, weather, and
long-term planning.
Drainage
RSA team members noted that Route 20 can become flooded in the vicinity of the Route 9
overpass. It was suggested that leaves and other debris build up in the catch basins, clogging
them. An RSA team member noted that flooding is sometimes so severe that vehicles stall in the
roadway.
Lighting
RSA team members suggested that the new interchange configuration can be confusing to
motorists who are unfamiliar with the interchange, and that confusion is amplified when it is dark
outside. Three of the 13 crashes that occurred on the Route 20 mainline between October 1, 2011
and August 28, 2012 occurred after dark, including one vehicle that struck a deer.
Signage
The RSA team noted that the interchange can be confusing to motorists unfamiliar with the area, and that there are more of these motorists than ever due to the new developments that have been built over the last three years. RSA team members noted several instances of signage that was unnecessary, redundant, or not visible to motorists. One crash occurred when a motorist traveling on Route 20 westbound stopped suddenly because he was looking for the entrance to the on-ramp to Route 9 that he had already passed. The guide sign for the entrance to the Route 9 eastbound ramp the motorist was likely looking for is located very Guide signage on Route 20 is not visible
close to the underpass under Route 9, and is not visible until motorists are under the underpass.
until the motorist is already in the underpass. The same problem occurs along route 20, where the visibility of
the guide sign for Route 9 westbound is blocked by the bridge abutment. RSA team members also stated that lane use along Route 20 is unclear as there is limited lane use
signage to indicate lane use. Finally, a team member commented that some motorists unfamiliar
with the area may be misled by out-of-date maps and GPS devices.
Page 23
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Weather
RSA team members noted that the time period
that the crash data was taken (October 1, 2011
through August 28, 2012) had few instances of
snow; however, due to a mild winter in
2011/2012, it is not known how safe the
interchange with the new configuration will
operate in snow weather conditions or when ice
is on the road. Two of the 110 crashes reported in
the time frame occurred when snow was on the
roadway.
A vehicle that appears to have slid off the
road in snowy conditions just after the
Just after the RSA was completed, a team
RSA.
member noted that a motorist appeared to have
lost control of his vehicle on a snow-covered
surface, running over the curb, and hitting a guide sign, at the Route 20 westbound off-ramp to
Route 9 eastbound.
Long-Term Planning
In an effort to reduce weaving along Route 9, and to accommodate expected increases in traffic
volumes in the area, two of the ramps at the interchange were removed and traffic signals were
installed along Route 20. Team members noted that the existing Route 9 bridge and abutments
limit the capacity along Route 20 and the ability to perform any widening of Route 9 within the
interchange, restricting the ability to add deceleration lanes for traffic utilizing the two remaining
loop ramps.
Potential Enhancements:
1. Remove debris from all drainage structures along Route 20, where possible, to help
minimize flooding on Route 20.
2. Consider the safety benefits of adding additional lighting along Route 9 and Route 20
within the study area, particularly at ramp intersections and major commercial driveways,
while considering the costs of power and maintenance.
3. Relocate guide signage along Route 20 eastbound for Route 9 westbound that is currently
blocked by the bridge abutment so that it is more visible.
4. Relocate guide signage along Route 20 westbound for Route 9 eastbound that is currently
blocked by the bridge abutment so that it is more visible.
5. Reevaluate all guide signage in the vicinity of the interchange and remove unnecessary
signage, relocate difficult-to-see signage to more visible areas, and consider the use of
overhead guide/lane use signage where feasible.
Page 24
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
6. Monitor safety conditions at the interchange during snow/ice conditions for impact to
future redesign efforts.
7. As part of long-term planning considerations, reevaluate interchange configuration,
geometry, and traffic control. Consider the safety benefits of widening Route 9 and Route
20 to accommodate geometric changes such as the addition of acceleration and
deceleration lanes, etc.
Page 25
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Potential Safety Enhancements
Based on its observations and discussions, the RSA team identified the issues and possible enhancements
that could improve safety at the interchange of Route 9 and 20 in Northborough. Many of the
enhancements identified during the RSA may require further design work or consideration to determine
the feasibility of making some of the improvements.
Short-term enhancements include:

Trim overgrown vegetation;

Maintain drainage structures;

Improve pavement markings; and

Improve signage.
To enhance the safety of the intersection, the long-term enhancements are to:

Improve interchange geometry;

Improve queuing/operating conditions;

Improve guide and wayfinding signage; and

Improve lane use markings.
Table 2 summarizes these safety issues, possible enhancements, estimated safety payoff, time frame, cost,
and responsibility. Safety payoff estimates are based on engineering judgment and are categorized as
low, medium, and high. The time frame is categorized as short-term (<1 year), mid-term (1 to 3 years), or
long-term (typically >3 years). Long-term improvements are typically considered to be substantial
improvements with an expected time frame for implementation greater than 3 years. The costs are
categorized as low (<$10,000), medium ($10,000 to $50,000), or high (>$50,000). It is the responsibility
of MassDOT to ensure that the designer incorporates the relevant safety enhancements identified as part
of this RSA. The RSA is intended to identify potential safety improvements that can be evaluated and
included as part of the design process for the reconstruction. The short-term low-cost potential
improvements could be considered by the responsible agency for implementation prior to reconstruction.
Page 26
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Table 2. Summary of Potential Safety Enhancements
Location
Safety Enhancement
Consider the appropriateness of replacing existing stop
signs (R1-1) at the end of the ramp with oversized signage
and add retroreflective tape on sign posts to improve their
visibility.
Safety
Payoff
Low
Consider the appropriateness of providing speed advisory
signage (W13-3) at the entrance to the ramp to reduce
Low
Ramp #1:
speeds on the ramp.
Route 20 onConsider the appropriateness of trimming, or removing, the
ramp to
group of trees located just east of the ramp approach so
Route 9
Low
that vehicles traveling on the ramp can see oncoming traffic
westbound
traveling along Route 9 westbound
Remove guide sign for Route 9 located at the end of the
ramp on the left-hand side and relocate the existing stop
Low
sign to a separate post.
Consider the feasibility of adding an acceleration lane on
Route 9 westbound to facilitate a safe merge from the
ramp; replace signage as appropriate.
High
Time
Frame
Cost
Responsibility
Shortterm
Medium MassDOT
Shortterm
High
MassDOT
Shortterm
Low
MassDOT
Shortterm
Low
MassDOT
Longterm
High
MassDOT
Page 27
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Table 2. Summary of Potential Safety Enhancements (Continued)
Location
Ramp #2:
Route 9
westbound
off-ramp to
Route 20
westbound
Safety Enhancement
Consider the feasibility and safety benefits of softening the
radius of the off-ramp and creating a T-intersection at the
end of the off-ramp at Route 20 westbound to improve sight
lines.
Consider the appropriateness of adding signalization to the
ramp at its intersection with Route 20 if a signal is
warranted at the location, while considering impacts to the
ramp’s capacity. Also consider queue detection to prevent
vehicle backup onto Route 9.
Maintain, and/or remove, trees/vegetation on the inside
radius of the ramp so that approaching vehicles can see
vehicles queuing at the ramp’s stop line at Route 20.
Consider providing additional ramp speed advisory signage
(W13-3), and/or chevrons, at the entrance to the ramp to
warn motorists to reduce speeds on the ramp.
Consider replacing existing advanced “Stop Ahead” (W3-1)
sign along the ramp, with one equipped with flashing lights
to improve visibility, to further encourage caution when
approaching Route 20.
Safety
Payoff
Time
Frame
Cost
Responsibility
High
Longterm
High
MassDOT
High
Longterm
High
MassDOT
Low
Shortterm
Low
MassDOT
Low
Shortterm
Low
MassDOT
Low
Shortterm
Medium MassDOT
Page 28
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Table 2. Summary of Potential Safety Enhancements (Continued)
Location
Safety Enhancement
Safety
Payoff
Time
Frame
Consider the appropriateness and safety benefits of
providing a supplemental signal indication at the end of the
MidMedium
ramp to improve visibility of the signal indication for
term
vehicles either stopped at, or approaching, the stop line.
Ramp #3:
Route 9
westbound
off-ramp to
Route 20
eastbound
Consider the feasibility of repositioning or reorienting
existing signal heads so that they are more visible to
motorists at or ahead of the stop line.
Consider providing additional ramp speed advisory signage
(W13-3) at the entrance to the ramp to reduce speeds on
the ramp.
Consider the appropriateness of providing advanced
“Signal Ahead” (W3-3) signage on the ramp.
Consider trimming overgrown vegetation along the south
side of Route 20 to improve sightlines for vehicles
attempting to make a right turn on red at the ramp stop line.
Consider trimming overgrown vegetation along the north
side of the ramp to improve the visibility of the signal
indications and the back of the traffic queue.
Cost
Responsibility
Medium MassDOT
Low
Shortterm
Low
MassDOT
Low
Shortterm
Low
MassDOT
Low
Shortterm
Low
MassDOT
Low
Shortterm
Low
MassDOT
Low
Shortterm
Low
MassDOT
Page 29
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Table 2. Summary of Potential Safety Enhancements (Continued)
Location
Safety Enhancement
Consider the feasibility of softening the radius of the offramp to create a T-intersection between the Route 9
eastbound off-ramp to Route 20 eastbound, which would
Ramp #4:
make it easier for vehicles to merge onto Route 20 and
Route 9
make it easier for queued vehicles to see to approaching
eastbound
vehicles.
off-ramp to
Consider providing additional ramp speed advisory signage
Route 20
(W13-3) and chevrons along the ramp to warn motorists
eastbound
and reduce speeds on the ramp.
Consider the appropriateness of providing advanced “Stop
Ahead” (W3-1) signage on the ramp.
Consider the safety benefits re-striping the existing dashed
white lane line to a solid white lane line to reinforce that
traffic from Route 20 eastbound and Route 20 westbound
may travel in two separate lanes for a short distance.
Ramp #5:
Route 20 on- Consider the use of recessed pavement markings for
increased visibility.
ramp to
Route 9
Consider the appropriateness and safety benefits of
eastbound
implementing geometric changes to force a deliberate rightturn from Route 20 eastbound onto the ramp to decrease
speeds on the ramp if pavement marking improvements do
not reduce the number of crashes on the ramp.
Consider the appropriateness of providing additional ramp
speed advisory signage (W13-3) and chevrons along the
Ramp #6:
ramp to warn motorist and reduce speeds on the ramp.
Route 9
Add control improvements at the ramp’s intersection with
eastbound
Route 20.
off-ramp to
Route 20
Consider the feasibility of using pavement markings to
westbound
delineate the deceleration lane to clarify lane use for
motorists.
Safety
Payoff
Time
Frame
Cost
Responsibility
High
Longterm
High
MassDOT
Low
Shortterm
Low
MassDOT
Low
Shortterm
Low
MassDOT
Medium
Shortterm
Low
MassDOT
High
Longterm
High
MassDOT
Low
Shortterm
Low
MassDOT
Medium
Midterm
Medium MassDOT
Low
Shortterm
Low
MassDOT
Page 30
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Table 2. Summary of Potential Safety Enhancements (Continued)
Location
Area-Wide
Safety Enhancement
Safety
Payoff
Time
Frame
Cost
Responsibility
Remove debris from all drainage structures along Route
20, where possible, to help minimize flooding on Route 20.
Low
Shortterm
Low
MassDOT
Consider the safety benefits of adding additional lighting
along Route 9 and Route 20 within the study area,
particularly at ramp intersections and major commercial
driveways.
Medium
Longterm
High
MassDOT
Relocate guide signage along Route 20 eastbound for
Route 9 westbound that is currently blocked by the bridge
abutment so that it is more visible.
Low
Shortterm
Low
MassDOT
Medium
Shortterm
Low
MassDOT
Low
Longterm
Medium MassDOT
Relocate guide signage along Route 20 westbound for
Route 9 eastbound that is currently blocked by the bridge
abutment so that it is more visible.
Reevaluate all guide signage in the vicinity of the
interchange and remove unnecessary signage, relocate
difficult-to-see signage to more visible areas, and consider
the use of overhead guide/lane use signage where
feasible.
Monitor safety conditions at the interchange during
snow/ice conditions for impact to future redesign efforts.
Low
Longterm
Low
MassDOT/Central
Massachusetts
Regional
Planning
Commission
(CMRPC)
Page 31
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Table 2. Summary of Potential Safety Enhancements (Continued)
Location
Safety Enhancement
Area-Wide
As part of long-term planning considerations, reevaluate
interchange configuration, geometry, and all traffic control.
Consider the safety benefits of widening Route 9 to
accommodate geometric changes such as the addition of
acceleration and deceleration lanes, etc.
Safety
Payoff
High
Time
Frame
LongTerm
Cost
High
Responsibility
MassDOT/
Central
Massachusetts
Regional
Planning
Commission
(CMRPC)
Page 32
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Appendix A. RSA Meeting Agenda Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Appendix B. RSA Audit Team Contact List Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Appendix C. Detailed Crash Data 1
2
3
4
Crash
Date
m/d/y
8/28/12
8/27/12
8/25/12
8/25/12
5
6
7
8
9
10
11
12
Crash Data Summary Table
Intersection of Belmont St. (Rt. 9) and Southwest Cutoff Rt. 20; Northborough, MA
10/1/2011 - 8/28/2012
Weather
Light Condition
Condition Road Surface Driver Contributing Code
Ages
Type
Type
Type
Type
D1
D2
Daylight
Clear
Dry
Other improper action
44
57
Daylight
Clear
Dry
Inattention
48
28
Daylight
Clear
Dry
Other improper action
56
39
Dusk
Clear
Dry
Inattention
64
18
Tuesday
Monday
Saturday
Saturday
2:17 PM
2:55 PM
3:23 PM
7:10 PM
Manner of Collision
Type
Rear-end
Rear-end
Rear-end
Rear-end
8/24/12
Friday
11:17 AM
Rear-end
Daylight
Clear
Dry
Other improper action
31
31
8/21/12
8/9/12
8/8/12
8/8/12
8/5/12
8/3/12
8/3/12
Tuesday
Thursday
Wednesday
Wednesday
Sunday
Friday
Friday
10:11 AM
1:11 PM
1:02 PM
1:28 PM
11:46 AM
3:41 PM
12:19 PM
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Daylight
Daylight
Daylight
Daylight
Daylight
Daylight
Daylight
Clear
Clear
Clear
Clear
Clear
Clear
Clear
Dry
Dry
Dry
Dry
Dry
Dry
Dry
Other improper action
Other improper action
Other improper action
Other improper action
Other improper action
Followed too closely
Inattention
55
23
67
75
36
36
24
29
71
23
19
32
49
48
13 7/30/12
Monday
6:33 PM
Angle
Daylight
Clear
Dry
Distracted
18
74
14 7/27/12
15 7/27/12
16 7/25/12
Friday
Friday
Wednesday
9:55 AM
8:02 AM
4:35 PM
Rear-end
Rear-end
Head on
Daylight
Daylight
Daylight
Cloudy
Cloudy
Clear
Dry
Dry
Dry
25
67
49
50
23
29
17 7/20/12
18 7/19/12
Friday
Thursday
11:15 PM
8:26 PM
Rear-end
Rear-end
Dark - lighted roadway Clear
Dusk
Clear
Inattention
Inattention
Failed to yield to right of way
Disregarded traffic signs,
signals, road markings
Inattention
52
42
41
26
#
Crash Day
Time of Day
Dry
Dry
19
20
21
22
23
24
25
7/19/12
7/17/12
7/16/12
7/13/12
7/11/12
7/11/12
7/9/12
Thursday
Tuesday
Monday
Friday
Wednesday
Wednesday
Monday
3:30 PM
4:50 PM
5:34 PM
9:32 PM
7:36 PM
5:10 PM
7:04 PM
Single Vehicle Crash
Rear-end
Rear-end
Single Vehicle Crash
Rear-end
Rear-end
Rear-end
Daylight
Daylight
Daylight
Dark - lighted roadway
Daylight
Daylight
Daylight
Clear
Clear
Clear
Clear
Clear
Clear
Clear
Dry
Dry
Dry
Dry
Dry
Dry
Dry
26
27
28
29
7/7/12
7/6/12
7/2/12
6/25/12
Saturday
Friday
Monday
Monday
6:10 PM
3:57 PM
6:56 PM
9:27 PM
Rear-end
Rear-end
Rear-end
Rear-end
Daylight
Daylight
Daylight
Dark - lighted roadway
Clear
Clear
Cloudy
Cloudy
Dry
Dry
Dry
Wet
30 6/19/12
Tuesday
6:49 PM
Rear-end
Daylight
Clear
Dry
Friday
Tuesday
Thursday
Sunday
Friday
Wednesday
4:06 PM
11:44 AM
7:24 AM
11:47 AM
8:43 PM
1:39 PM
Angle
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Daylight
Daylight
Daylight
Daylight
Dark - lighted roadway
Daylight
Clear
Clear
Clear
Clear
Cloudy
Clear
Saturday
Saturday
11:12 AM
2:25 PM
Angle
Rear-end
Daylight
Daylight
Tuesday
Tuesday
Friday
Thursday
Monday
Sunday
Saturday
Thursday
Tuesday
Saturday
Wednesday
Tuesday
10:47 PM
1:38 PM
6:59 PM
12:52 AM
8:30 PM
7:21 PM
8:52 AM
7:02 PM
2:23 PM
12:22 AM
8:39 PM
7:42 PM
Single Vehicle Crash
Rear-end
Rear-end
Single Vehicle Crash
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Single Vehicle Crash
Rear-end
Rear-end
Dark - lighted roadway
Daylight
Dusk
Dark - lighted roadway
Dark - lighted roadway
Daylight
Daylight
Daylight
Daylight
Dark - lighted roadway
Dark - lighted roadway
Dark - lighted roadway
31
32
33
34
35
36
6/15/12
6/12/12
6/7/12
6/3/12
6/1/12
5/30/12
37 5/26/12
38 5/26/12
39
40
41
42
43
44
45
46
47
48
49
50
5/22/12
5/22/12
5/18/12
5/17/12
5/7/12
5/6/12
5/5/12
5/3/12
5/1/12
4/14/12
4/18/12
4/10/12
Comments
D3
Vehicle 1 began to pull forward and then stopped quickly causing Vehicle 2 to
rear-end it
Vehicle 1 delayed on green light, Vehicle 2 assumed Vehicle 1 already pulled
forward
Operator 2 was distracted while waiving to an uninvolved vehicle and
possibly failed to stop for red light
Vehicle 1 was yielding to merging traffic which caused Vehicle 2 to rear-end it
Vehicle 1 pulled to side of street thinking that an uninvolved vehicle behind
her was going to pass. In doing so Vehicle 1 struck the curbing causing 2 flat
tires.
Other improper action
Inattention
Failed to yield to right of way
Inattention
Inattention
Inattention
Inattention
Disregarded traffic signs,
signals, road markings
Inattention
Inattention
Inattention
63
49
54
37
51
49
40
45
43
25
27
19
43
28
37
65
30
19
28
21
22
60
26
Dry
Dry
Dry
Dry
Dry
Dry
Inattention
Disregarded traffic signs,
signals, road markings
Inattention
Inattention
Other improper action
Inattention
Other improper action
41
51
26
42
66
48
47
17
25
42
19
62
Cloudy
Clear
Dry
Dry
Made an improper turn
Other improper action
30
49
39
17
Cloudy
Rain
Clear
Clear
Clear
Clear
Cloudy
Cloudy
Rain
Clear
Clear
Clear
Wet
Wet
Dry
Dry
Dry
Dry
Dry
Wet
Wet
Dry
Dry
Dry
Inattention
Inattention
Inattention
Inattention
Inattention
Inattention
Inattention
Inattention
Inattention
No Improper Driving
Inattention
Inattention
22
35
26
38
38
63
57
33
27
36
33
32
Vehicle 1 began to pull forward and then stopped quickly due to emergency
vehicles traveling on Rt 9 causing Vehicle 2 to rear-end it
Vehicle 2 failed to stop at red light
Vehicle 1 attempted to enter parking lot by crossing double solid line &
multiple lanes of traffic
Vehicle swerved off road to avoid hitting vehicle stopped at stop sign. Ended
up hitting the stop sign on the side of road instead.
23
34
Dump truck forgot to lower back bed and struck overhanging light pole
21
80
22
57
18
Struck deer in roadway
16
72
Crash
Date
Crash Day
m/d/y
#
Time of Day
Manner of Collision
Type
Crash Data Summary Table
Intersection of Belmont St. (Rt. 9) and Southwest Cutoff Rt. 20; Northborough, MA
10/1/2011 - 8/28/2012
Weather
Light Condition
Condition Road Surface Driver Contributing Code
Ages
Type
Type
Type
Type
D1
D2
51 4/10/12
52 4/7/12
Tuesday
Saturday
7:05 PM
3:45 PM
Rear-end
Rear-end
Daylight
Daylight
Clear
Clear
Dry
Dry
Inattention
Other improper action
36
27
4/5/12
3/31/12
3/24/12
3/23/12
3/22/12
Thursday
Saturday
Saturday
Friday
Thursday
6:10 PM
1:59 PM
3:35 PM
10:46 AM
8:36 AM
Single Vehicle Crash
Rear-end
Rear-end
Rear-end
Rear-end
Daylight
Daylight
Daylight
Daylight
Daylight
Clear
Clear
Clear
Clear
Clear
Dry
Dry
Dry
Dry
Dry
62
77
69
53
54
52
35
32
48
58 3/15/12
Thursday
7:12 PM
Rear-end
Dark - lighted roadway Cloudy
Dry
Inattention
Other improper action
Other improper action
Inattention
Inattention
Disregarded traffic signs,
signals, road markings
55
16
59 3/15/12
60 3/11/12
Thursday
Sunday
3:02 PM
11:12 AM
Rear-end
Rear-end
Daylight
Daylight
Clear
Clear
Dry
Dry
Other improper action
Followed too closely
72
27
17
22
61 3/10/12
Saturday
11:14 PM
Single Vehicle Crash
Dark - lighted roadway Clear
Dry
No Improper Driving
18
62 3/9/12
63 3/9/12
64 3/4/12
Friday
Friday
Sunday
3:16 PM
3:08 PM
11:44 AM
Rear-end
Rear-end
Rear-end
Daylight
Daylight
Daylight
Clear
Cloudy
Clear
Dry
Dry
Dry
26
51
38
21
39
17
65 3/2/12
66 2/24/12
Friday
Friday
6:59 PM
4:41 PM
Rear-end
Rear-end
Dark - lighted roadway Cloudy
Daylight
Rain
Dry
Wet
64
60
unk
58
67 2/18/12
68 2/18/12
Saturday
Saturday
6:24 PM
1:45 PM
Angle
Rear-end
Dark - lighted roadway Clear
Daylight
Clear
Dry
Dry
Inattention
Other improper action
Other improper action
Disregarded traffic signs,
signals, road markings
Inattention
Failure to keep in proper lane
or running off road
Other improper action
unk
26
61
25
69 2/13/12
Monday
12:33 PM
Rear-end
Daylight
Clear
Dry
No Improper Driving
36
59
53
54
55
56
57
Comments
D3
Vehicle 1 stopped to avoid collision with uninvolved vehicle, Vehicle 2 was
not looking and rear-ended Vehicle 1
50
28
Vehicle accelerates off road and hits brick wall in driveway of #380 SW
Cutoff. Operator claims to have been cut off by an unknown vehicle.
70
71
72
73
74
2/6/12
1/30/12
1/28/12
1/28/12
1/25/12
Monday
Monday
Saturday
Saturday
Wednesday
12:43 PM
7:36 AM
5:10 PM
4:11 PM
3:42 PM
Rear-end
Head on
Rear-end
Rear-end
Rear-end
Daylight
Daylight
Dusk
Daylight
Daylight
Clear
Clear
Clear
Clear
Clear
Dry
Dry
Dry
Dry
Dry
No Improper Driving
Failed to yield to right of way
Inattention
Inattention
Other improper action
63
55
39
29
64
25
20
23
17
33
75
76
77
78
79
80
81
1/25/12
1/22/12
1/22/12
1/21/12
1/14/12
1/12/12
1/12/12
Wednesday
Sunday
Sunday
Saturday
Saturday
Thursday
Thursday
12:11 PM
4:49 PM
11:05 AM
9:18 AM
3:26 PM
1:50 PM
9:50 AM
Rear-end
Rear-end
Rear-end
Single Vehicle Crash
Rear-end
Rear-end
Rear-end
Daylight
Daylight
Daylight
Daylight
Daylight
Daylight
Daylight
Clear
Cloudy
Clear
Snow
Clear
Cloudy
Snow
Dry
Wet
Wet
Snow
Dry
Wet
Snow
Other improper action
Inattention
Other improper action
No Improper Driving
Inattention
Other improper action
Other improper action
59
59
27
30
25
65
48
45
23
53
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
1/10/12
12/30/11
12/29/11
12/28/11
12/26/11
12/19/11
12/17/11
12/15/11
12/14/11
12/12/11
12/8/11
12/6/11
12/3/11
12/1/11
11/26/11
11/22/11
11/14/11
11/9/11
11/6/11
Tuesday
Friday
Thursday
Wednesday
Monday
Monday
Saturday
Thursday
Wednesday
Monday
Thursday
Tuesday
Saturday
Thursday
Saturday
Tuesday
Monday
Wednesday
Sunday
10:40 PM
1:44 PM
12:28 PM
10:04 PM
8:30 AM
6:01 PM
3:10 PM
5:41 PM
7:13 PM
5:52 PM
8:19 PM
3:22 PM
5:54 PM
2:12 PM
2:11 PM
5:36 PM
11:26 AM
2:21 PM
4:05 PM
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Dark - lighted roadway
Daylight
Daylight
Dark - lighted roadway
Daylight
Dark - lighted roadway
Daylight
Dark - lighted roadway
Dark - lighted roadway
Dark - lighted roadway
Dark - lighted roadway
Daylight
Dark - lighted roadway
Daylight
Daylight
Dark - lighted roadway
Daylight
Daylight
Dusk
Clear
Cloudy
Clear
Clear
Clear
Clear
Clear
Rain
Clear
Clear
Clear
Rain
Clear
Clear
Clear
Clear
Clear
Clear
Clear
Dry
Dry
Dry
Dry
Dry
Dry
Dry
Wet
Dry
Dry
Dry
Wet
Dry
Dry
Dry
Dry
Dry
Dry
Dry
No Improper Driving
Inattention
Other improper action
Inattention
Other improper action
Inattention
Inattention
Inattention
No Improper Driving
Inattention
Inattention
Inattention
Inattention
Inattention
Other improper action
Inattention
Other improper action
Inattention
Inattention
65
45
27
29
60
43
39
53
53
42
29
30
28
52
70
41
61
72
51
22
42
22
39
23
74
25
51
19
26
20
59
43
30
16
57
44
51
22
Vehicle 1 stopped suddenly while looking for the on-ramp to Rt 9 which he
had already passed
Operator herd a large "bang" and lost steering to vehicle causing it to strike a
large wooden sign.
Vehicle 1 stopped because of crash on the off-ramp, Vehicle 2 could not stop
in time
Hit and run crash
Vehicle 2 crossed over a painted traffic island in an attempt to enter #375 SW
Cutoff
Vehicle 1 stopped for uninvolved TT unit in front, Vehicle 2 rear-ended
Vehicle 1
Vehicle 1 and 2 were both stopped at stop sign. In an attempt to avoid being
rear-ended by an unknown, fast approaching vehicle , Vehicle 2 tries to pull
away, making contact with Vehicle 1
Operator 2 claims to have pushed in on the clutch and brakes but car moved
forward rear-ending Vehicle 1
Vehicle applied brakes, lost control of vehicle and hit median barrier
65
51
54
unk
Road conditions were slippery with snow
Vehicle 3 rear ended Vehicle 1 which then rear-ended Vehicle 2. Vehicle 3
left the scene
Vehicle 1 slowed down to merge with traffic causing Vehicle 2 to rear-end it
#
Crash
Date
Crash Day
m/d/y
Time of Day
Manner of Collision
Type
Crash Data Summary Table
Intersection of Belmont St. (Rt. 9) and Southwest Cutoff Rt. 20; Northborough, MA
10/1/2011 - 8/28/2012
Weather
Light Condition
Condition Road Surface Driver Contributing Code
Ages
Type
Type
Type
Type
D1
D2
101 10/25/11 Tuesday
102 10/22/11 Saturday
8:23 AM
2:48 PM
Sideswipe, same direction
Rear-end
Daylight
Daylight
Clear
Clear
Dry
Dry
103 10/20/11 Thursday
7:40 PM
Rear-end
Dusk
Clear
11:25 AM
1:52 PM
1:54 PM
7:00 PM
12:38 PM
10:50 AM
1:16 PM
Single Vehicle Crash
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Rear-end
Daylight
Daylight
Daylight
Dark - lighted roadway
Daylight
Daylight
Daylight
Rain
Clear
Rain
Clear
Clear
Clear
Cloudy
104
105
106
107
108
109
110
10/19/11
10/16/11
10/15/11
10/14/11
10/8/11
10/7/11
10/2/11
Wednesday
Sunday
Saturday
Friday
Saturday
Friday
Sunday
Summary based on Crash Reports obtained from the Northborough Police Department. 15 operator reports and 52 incident reports were also located at this site but were not included in investigation data.
57
40
50
63
Dry
Inattention
Inattention
Disregarded traffic signs,
signals, road markings
40
40
Wet
Dry
Wet
Dry
Dry
Dry
Wet
Over-correcting/over-steering
Inattention
Inattention
Inattention
Inattention
Inattention
Failed to yield to right of way
62
37
25
37
62
56
55
Comments
D3
Vehicle 2 side-swiped the corner of Vehicle 1's trailer which had been
disconnected from tractor unit
Operator claims that there was a mechanical failure that made the vehicle
turn to the right & hit brush on side of road
18
47
64
42
21
55
Crash Data Summary Tables and Charts
Intersection of Belmont St. (Rt. 9) and Southwest Cutoff Rt. 20; Northborough, MA
CRASH MONTH
20%
15%
15%
11%
10%
11%
11%
12%
9%
6%
5%
5%
5%
11%
5%
0%
0%
J
F
M
A
M
J
J
A
S
O
N
D
**Note data was only taken from October 2011 to August 2012
CRASH DAY OF WEEK
25%
20%
15%
10%
5%
0%
20%
18%
13%
13%
18%
13%
5%
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
CRASH TIME OF DAY
35%
40%
30%
27%
24%
20%
10%
0%
7%
7%
0%
6-10AM
10-2PM
2-6PM
6-10PM
10-2AM
2-6AM
CRASH MANNER OF COLLISION
100%
85%
80%
60%
40%
20%
8%
4%
1%
0%
2%
0%
0%
Head on
Rear to
Rear
Unknown
0%
Single
Vehicle
Crash
Rear-end
Crash Summary Data Table_10_10_12
Angle
Sideswipe, Sideswipe,
same
opposite
direction
direction
4 of 5
10/10/2012
Crash Data Summary Tables and Charts
Intersection of Belmont St. (Rt. 9) and Southwest Cutoff Rt. 20; Northborough, MA
80%
60%
40%
20%
0%
CRASH LIGHT CONDITION
73%
22%
5%
0%
Daylight
Dawn
Dusk
Dark Lighted
Roadway
0%
0%
0%
0%
Dark Roadway
not lighted
Dark unknown
roadway
lighting
Other
Unknown
CRASH WEATHER CONDITION
0%
0%
Severe
Crosswinds
0%
Unknown
0%
Fog, Smog,
Smoke
0%
Other
0%
Blowing
sand, snow
2%
Sleet, Hail,
Freezing
Rain
6%
Rain
Cloudy
15%
Snow
77%
Clear
100%
80%
60%
40%
20%
0%
CRASH ROAD SURFACE
100%
80%
60%
40%
20%
0%
85%
13%
Dry
Wet
2%
0%
Snow
Ice
0%
0%
Sand,
Water
mud, dirt, (standing,
oil, gravel moving)
0%
0%
0%
Slush
Other
Unknown
CRASH DRIVER AGES
30%
25%
16%
20%
10%
16%
18%
12%
9%
4%
0%
0%
15-20
21-29
Crash Summary Data Table_10_10_12
30-39
40-49
50-59
5 of 5
60-69
70-79
80+
10/10/2012
Road Safety Audit
Interchange of Routes 9 and 20, Northborough, MA
Prepared by Howard/Stein-Hudson Associates, Inc.
Appendix D. Additional Information