SAFETY STUDY
Runaway Truck Ramp
Route 2 (Taconic Trail) at Route 7 (Cold Spring Road)
Town of Williamstown
December 18, 2012
Prepared For:
MassDOT Highway Division
Prepared By:
BETA Group, Inc.
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.
Table of Contents
Background .................................................................................................................................1
Project Team ...............................................................................................................................1
Existing Conditions.....................................................................................................................2
Observations................................................................................................................................6
Potential Safety Enhancements .................................................................................................8
Summary of Recommendations...............................................................................................11
List of Appendices
Appendix A.
Appendix B.
Project Team
FHWA Technical Advisory
List of Figures
Figure 1.
Figure 2.
Location Map ......................................................................................................................... 3
Location Detail ....................................................................................................................... 4
List of Tables
Table 1.
Table 2.
Table 3.
Participating Team Members ................................................................................................. 1
Estimated Time Frame and Costs Breakdown ....................................................................... 8
Potential Safety Enhancement Summary ............................................................................. 12
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.
Background
MassDOT Highway Division District 1 was asked by the Town of Williamstown to evaluate the existing
runaway truck ramp at the intersection of Route 2 (Taconic Trail) and Route 7 (Cold Spring Road) in
Williamstown following a fatal crash in June of 2011 in which a tractor trailer commercial vehicle
bypassed the truck ramp and crossed the intersection, collided with large concrete block barriers, and
eventually came to rest in a wooded area east of the roadway. MassDOT assembled the team described
below to study the details of the fatal crash, conduct a review of the geometric and other related features
of the area, identify safety issues and contributing factors, and identify both short and long term safety
improvements that can be implemented related to the truck ramp and truck operations both at the
intersection and along the Route 2 downgrade approaching Route 7.
Project Team
A safety study of the existing runaway truck ramp at the intersection of Route 2 (Taconic Trail) and Route
7 (Cold Spring Road) in Williamstown was held on November 5, 2012 at the Williamstown Town Hall.
As indicated in Table 1, the project team assembled consisted of representatives from State, Regional and
Local agencies and included a cross-section of engineering, planning, safety, enforcement and emergency
response expertise. The team included police personnel familiar with truck operations and truck crashes,
as well as a truck driver familiar with the area.
Table 1. Participating Team Members
Audit Team Member
Agency/Affiliation
Bonnie Polin
MassDOT Highway Division – Safety Section
Lisa Schletzbaum
MassDOT Highway Division – Safety Section
Doug Plachcinski
Berkshire Regional Planning Commission (BRPC)
Mark Moore
MassDOT Highway Division – District 1
Kevin Chiang
MassDOT Highway Division – District 1
Pat Tierney
MassDOT Highway Division – District 1
Jonathan Bates
Massachusetts State Police
Kyle Johnson
Williamstown Police Chief
Dave McKearney
Massachusetts State Police
Joel Cooper
Filkins Transportation (Truck Driver)
Bob McCarthy Jr.
Abutter
Craig Pedercini
Williamstown Fire Chief
Tim Kaiser
Williamstown DPW Director
Greg Lucas
BETA Group, Inc.
Page 1
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.
Existing Conditions
The intersection of Route 2 (Taconic
Trail) and Route 7 (Cold Spring
Road), shown in Figure 1, is located in
Williamstown, approximately 2 miles
south of the town center. Route 2
extends eastward from Troy, NY and
the northern Albany, NY suburbs
through mountainous terrain to an
unsignalized T-intersection with
Route 7. Route 2 follows the Route 7
alignment north to the center of
Williamstown, and then returns to an
east-west alignment all the way to
Boston. Route 2 is known for its hilly
terrain and scenic views in the western
part of the state. Route 7 crosses the
Route 2 at Route 7
state in a north-south alignment,
providing access to the MassPike and Pittsfield to the south, and Bennington, VT to the north. Both routes
are functionally classified as a Rural Minor Arterial, and both are important regional routes.
Route 2 eastbound features a downhill grade for the entirety of its length from the New York state line to
Route 7, a distance of approximately 4 miles. The top of the hill is across the state line in New York,
although all hill warning signage in both New York and
Massachusetts is maintained by MassDOT. W7-1 Hill
warning signs have supplemental plaques alerting drivers of
the seven percent grade, a 30 mph advisory speed limit, and
a TRUCKS USE LOWER GEAR message, as seen at right.
The roadway has frequent horizontal curves in conjunction
with the downhill grade, and is signed for 30 mph for trucks
and 35 mph for all other vehicles. It was noted by team
members that a “flat spot” exists approximately halfway
down the hill, which may give eastbound drivers a false
sense of security that they have finished traversing the
steepest part of the grade.
Route 2 intersects Route 7 (Cold Spring Road) from the west. Both intersecting roadways provide a single
travel lane in each direction in the vicinity of the intersection. The single eastbound travel lane widens at
the intersection to two marked lanes for a length of approximately 100 feet, providing separation for left
and right turning vehicles. The left turn to Route 7 northbound is under STOP control, while the right turn
lane is under yield control. The two lanes are separated by a small, triangular concrete island. The
eastbound and westbound lanes on the Route 2 leg are separated by a concrete and grass median
approximately 120 feet in length.
Page 2
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RUNAWAY
TRUCK RAMP
LEGEND
STUDY AREA
Route 2 Runaway
Truck Ramp
Safety Study
Williamstown, MA
Figure 1
Location Map
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.
Route 7 southbound has access to Route 2 westbound via a right turn lane under yield control, separated
by a triangular concrete and grass island. The A-Frame Bakery is located on the east side of Route 7 at the
intersection, and has concrete blocks along its frontage and along the back edge of its parking area,
assumedly to deter runaway vehicles that may cross the intersection. A currently closed former restaurant
site is located on the northwest corner of the intersection with driveway access on Route 7 at the
beginning of the southbound right turn lane. Lane configurations, islands and adjacent access points can
be seen in Figure 2.
Figure 2.
Location Detail
A runaway truck ramp was constructed at the intersection in 2002 to allow an opportunity for runaway
vehicles to safely depart the roadway. The ramp features a paved entry area leading to a gravel arrester
bed, which is intended to slow the forward progress of a runaway vehicle. The gravel bed is 25 feet in
width and approximately 725 feet in length. A stainless steel cable net is provided at the end of the ramp
to provide an additional means to capture an errant vehicle. It was noted that the effectiveness of the
gravel is diminished in the winter under freezing conditions. The ramp is known to have been used by
errant tractor trailers, and vehicle tracks were apparent on the day of the study, although team members
suggested that it may have been a smaller truck rather than a tractor trailer. It was mentioned by
MassDOT that the ramp is known to have been used effectively soon after completion. A rumble strip is
provided along the roadway edge line to alert drivers that may unintentionally cross into the paved entry
area for the ramp.
Page 4
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.
The specific crash considered for this study occurred on Wednesday, June 29th 2011 at approximately
8:20 AM. The crash report notes that the weather on June 29th was warm, with overcast skies and no
chance of precipitation. The vehicle was a typical tractor trailer with a driver and a single passenger. The
driver bypassed the runaway truck ramp, continued through the STOP-controlled intersection, through the
concrete barriers and across the grassy area beyond the barriers. The vehicle ultimately came to a stop
after crossing a stream and striking an uphill treed area. The vehicle suffered extensive damage, with its
cargo strewn about the landscape. The driver was unrestrained and suffered fatal injuries as a result of the
crash. The passenger was restrained by a seat belt and suffered non-life threatening injuries. An
evaluation of the vehicle following the crash revealed defects in the vehicle braking system. The driver
had been licensed to drive commercial vehicles in Massachusetts since 2006, although it is unknown if he
was familiar with the area as he is from eastern Massachusetts.
Page 5
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.
Observations
Following a brief discussion of the purpose of the study and the details of the crash, the project team was
asked to discuss safety issues and other factors related to the Route 2 approach, the intersection, and the
existing runaway truck ramp. In general, the existing ramp was designed according to standards but other
surrounding roadway conditions may create potential safety issues that reduce its effectiveness. Issues are
categorized into general topics as follows:

Visibility – The horizontal curvature of
the roadway, vegetation, a guardrail and
utility poles all may create obstructions
that prevent a driver from being able to
see the entry to the ramp. An emergency
easement was granted by the Town
following the fatal crash, and MassDOT
District 1 cleared trees and brush to
improve visibility in 2011.

Horizontal Curvature and Load Shifting –
In addition to its effect on visibility, the
horizontal curvature of the roadway may
impact the likelihood of a driver using
Visibility approaching ramp
the ramp. The truck entrance is near the
end of a reverse curve, requiring a driver to turn to the right immediately after navigating a turn to the
left. Team members familiar with the operations of fully loaded trucks indicated that the effect of load
shifting is felt by the driver, especially in a vehicle travelling at excessive speed. A driver who has
just shifted back to the right after a turn to the left may be hesitant to turn further to the right to enter
the truck ramp, fearing that the resultant load shift would overturn the vehicle. This threat, whether
real or perceived, may impact the likelihood that a driver would enter the runaway truck ramp.

Signage – Signage for the truck ramp and for the
grade was discussed as it relates to driver behavior on
the Route 2 downhill grade. Advance warning signs
meeting Manual on Uniform Traffic Control Devices
(MUTCD) guidelines are provided for the truck ramp
at 1 mile, ½ mile and at the ramp entry. It was noted
that an additional sign was added recently at the ramp
entry to further designate the ramp entry location. As
previously mentioned, W7-1 Hill signs are provided
at the top of the grade. Truck speed limit signs are
Signage approaching Route 7
provided intermittently along the downhill grade, and
the 30 mph truck speed limit signs are in fact larger than the 35 mph vehicle speed limit signs. All
signs within one mile of the ramp appear to be in good condition, although the reflectivity of the signs
at night is unknown.
Page 6
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.

Driver Behavior – Driver behavior and experience was discussed as an overall factor that can impact
a driver’s reaction to the other potential safety issues discussed above. An inexperienced driver may
travel down the hill at a greater speed than one more experienced with traversing steep grades, which
would then create a greater need for brakes at the bottom of the hill and a higher likelihood of brake
overheating or failure. An inexperienced driver may also fail to use the proper gear at the top of the
hill and attempt to downshift when already traveling at a high speed, which will not effectively reduce
the speed of the truck under those conditions. Finally, the effect of load shifting may be more of a
deterrent for an inexperienced driver of an out of control vehicle considering entry into the runaway
truck ramp. The downhill entry to the ramp may also look daunting to a driver, concerned about the
ramp’s potential effectiveness. A runaway truck at a high rate of speed provides the driver very little
decision time to consider entry into the ramp, and an inexperienced driver is less likely to be able to
make that decision and more likely to exhibit panic under those conditions. It was noted by a local
resident that trucks often stop at the bottom of the hill to cool their brakes, and that he has observed
brakes smoking or even on fire following the stress of braking on the Route 2 downgrade. It is
assumed that these trucks had adequate brakes to stop at the intersection at Route 7.

Rumble Strips – Rumble strips are provided along the solid white edge line in the vicinity of the truck
ramp entrance to alert vehicles that they have left the traveled way, much in the same way that rumble
strips are used along the shoulder edge line on highways. This is intended to prevent motorists from
inadvertently entering the paved area at the entrance to the truck ramp. It was suggested that this
rumble strip may also deter trucks from entering the ramp because it is counterintuitive to a typical
encounter with a rumble strip, which encourage a truck driver to shift back to the left to remain in the
traveled way.

Lighting – An overhead street light is provided at the entry to the ramp, with additional lighting
following the ramp on the Route 2 approach to Route 7. It was suggested that existing lighting does
not adequately light the ramp approach and ramp entry area.

Sun Glare – The potential for sun glare was discussed due to the east alignment of Route 2 at Route 7.
It was noted that sun glare is not a factor because the hills east of Route 7 block the early morning
sun.
Page 7
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.
Potential Safety Enhancements
Following a visit to the ramp location, team members were asked to recommend potential improvements
to address the safety issues identified and increase the overall safety of the Route 2 approach and the
runaway truck ramp. Specific recommendations are discussed in detail in this section and summarized in
Table 3. Each improvement considered has been categorized as short-term, mid-term or long-term based
on the definitions shown in Table 2. Additionally, a cost category has been assigned to each improvement
based on the parameters set forth in Table 2.
Table 2. Estimated Time Frame and Costs Breakdown
Time Frame
Short-term
<1 year
Costs
Low
Mid-term
1–3 years
Medium
Long-term
>3 years
High
<$10,000
$10,000–$50,000
>$50,000

Clear brush along and behind the existing guardrail before the truck ramp. Since clearing in 2011, low
brush has grown along the guardrail which may obstruct visibility of the ramp entrance area. This
brush should be cleared as a short-term, low cost improvement and continued maintenance should be
prioritized as a mid-term and long-term consideration.

Realign Route 2. Two realignment alternatives were discussed and are detailed herein. Both
alternatives are long-term, high cost improvements.
o Fill the wooded, sloped area on the south side of the roadway immediately prior to the truck
ramp entrance. This would flatten the existing horizontal curve to the right, and would lessen
or eliminate the effect of load shifting due to the existing reverse curve. This would require a
legislative act to allow
earthwork and tree removal in
an area designated as parkland.
This realignment option would
impact the intersection of
Route 2 and Old Farm Road,
and would also require
reconfiguration and
reconstruction of the existing
truck ramp, since the ramp
alignment must remain tangent
to the horizontal curve. This
realignment option would also
require extending an existing
culvert under Route 7.
Page 8
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.
o Cut the wooded, sloped area on the north side of the roadway at the beginning of the reverse
curve. This would flatten the existing horizontal curve to the left, which would also lessen or
eliminate the effect of load shifting due to the existing reverse curve. This would require land
taking, extensive slope work, and would impact the intersections at Old Farm Road and
Torrey Woods Road. Modification of this curve may also involve “chasing” curve point and
tangent changes into the existing curve to the right.

Reconfigure the ramp. This is a high-cost, long term improvement that focuses more directly on ramp
modifications rather than roadway modifications discussed above. It was suggested that the stainless
steel webbing system can be upgraded so that the ramp length can be shortened, which would allow
for a longer paved entry area and perhaps make entry to the ramp less formidable for the driver of a
runaway truck. Reconfiguration of the ramp may require slight modification of the horizontal curve
adjacent to the current entrance to the ramp.

Relocate the two utility poles in the line of sight at the entrance to the truck ramp. Two utility poles
on the south side of the roadway are within the line of sight for a driver approaching the ramp. These
poles should be reset so that they do not create a potential visibility obstruction. This is a mid-term,
high cost improvement.

Remove rumble strips along the roadway edge and provide post mounted red delineators along both
sides of the paved ramp entry area. This recommendation was developed by the project team
following the meeting, and supports the notion that rumble strips intended to deter non-trucks from
entering the ramp will also deter trucks from entering the ramp. FHWA guidance on rumble strips,
included in the Appendix, states that rumble strips are designed primarily to assist drowsy or other
inattentive drivers who may unintentionally drift over the edge line. Red delineators will provide the
visual delineation to drivers of the truck ramp off the traveled way without potentially deterring
trucks from entering the ramp. Red is recommended instead of yellow or white because it more
obviously delineates the edge of the ramp to a runaway vehicle. Post mounted delineators should
follow MassDOT standards for delineation for guardrail termini. This is a mid-term, medium cost
improvement.

Upgrade lighting at the truck ramp entrance. It was noted that existing lighting begins at the entrance
to the ramp and continues to the intersection at Route 7. Additional lighting should be added so that
the area before the ramp is lighted. This is a mid-term, high cost improvement that should be
considered in conjunction with utility pole relocation. Existing lights are cobra-head style lights
mounted on existing utility poles.

Consider overhead signage at the truck ramp entrance. Existing signage at the ramp entrance is
located in advance of the ramp on the right side of the road and on the left side of the ramp at the end
of the paved ramp entrance. An overhead sign with a downward facing arrow would more clearly
alert drivers as to the location of the ramp entrance. The overhead sign could incorporate flashing
beacons and downward-facing flood lighting. This is a mid-term, medium cost improvement.

Verify distance of the overall downhill grade shown on W7-1 Hill signs at the top of the grade. The
distance of the downhill grade should be verified to ensure that signage displays the appropriate
information. This is a short-term, low cost improvement.
Page 9
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.

Construct an additional runaway truck ramp halfway down the downhill grade. This recommendation
was developed when considering whether a driver would be more likely to enter a truck ramp which
slopes uphill. Team members noted a runaway truck ramp on Route 57 in Sandisfield which has an
uphill alignment, and then considered if a location further up the hill could accommodate an uphill
sloping runaway truck ramp. It was noted that this would not be effective for trucks where the stress
of braking creates a failure beyond the location of this intermediate ramp, and that the intermediate
ramp cannot serve as a replacement for the existing ramp. This is a long-term, high cost improvement.
Truck Ramp on Route 57 in Sandisfield

Provide additional signage at the “flat spot” with flashing beacons. Additional W7-1 Hill signs should
be provided in this area with a supplemental plaque noting the remaining distance to confirm that
drivers have not finished traversing the downhill grade when they reach this point. Flashing beacons
attached to the sign will further alert drivers. This is a short-term, medium cost improvement.

Construct a roadside brake check area at the “flat spot”. It was suggested that in addition to advance
signage, the shoulder could be widened to allow trucks to pull off and test or rest brakes. Additional
signage in advance of this area would alert drivers to the upcoming grade and allow a driver that
might have concerns over braking to stop and rest the brakes before traversing the remainder of the
hill. This is a mid-term, medium cost improvement.

Consider reducing the advisory truck speed from 30 mph to 25 mph. This would require study to
determine if a reduction in the advisory speed is appropriate. This is a short-term, low cost
improvement.

Replace all hill, grade and runaway truck ramp signage with diamond grade high intensity yellow
sheeting. It was suggested by audit participants that existing signage is adequate; however, reflectivity
at night is unknown. Replacing all signs with high intensity signs will increase visibility and
awareness of the signs under all lighting conditions. This is a short-term, low cost improvement.
Page 10
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.

Install radar enhanced speed limit signs. Feedback signs showing a driver’s actual speed may alert
drivers that they are traveling at an excessive speed at a point before brake failure can potentially
occur. This is a short-term, medium cost improvement.

Coordinate with GPS manufacturers to inform drivers of the potential hazard. It was noted that this
can be done through a special GPS service marketed for truck drivers, but that few drivers choose to
purchase this service because of the cost difference over traditional consumer GPS units. This
improvement is not recommended due to its limited effectiveness.

Re-route trucks regionally from New York and Vermont. This potential consideration was discussed,
but is not recommended because of the coordination level involved. This improvement would also not
prevent inexperienced drivers without the knowledge of established truck routes from following
Route 2.
Summary of Recommendations
Table 3 summarizes potential recommendations discussed by the project team. The recommendations are
categorized based on the potential safety payoff, as well as by time frame and cost. The safety payoff is a
qualitative judgment of the effectiveness of the potential safety improvements. The cost is based on the
parameters set forth in Table 2. Long-term recommendations could be considered after short- and midterm recommendations have been evaluated.
Page 11
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.
Table 3. Potential Safety Enhancement Summary
Safety
Payoff
Responsibility
Time
Frame
Cost
Clear brush along and behind the existing guardrail before the truck ramp.
High
MassDOT
Short-term
Low
Realign Route 2. Further study may be required to determine if the options
discussed in the report are feasible and which one is preferred.
High
MassDOT
Long-term
High
Reconfigure the ramp by shortening the ramp, upgrading the stainless
steel webbing, adding a longer paved entry area and potentially modifying
the roadway curve.
High
MassDOT
Long-term
High
Visibility
Relocate the two utility poles in the line of sight at the entrance to the truck
ramp.
High
MassDOT
Mid-term
High
Rumble Strips
Remove rumble strips along the roadway edge and provide post mounted
red delineators along both sides of the paved entry to the truck ramp. Post
mounted delineators should follow MassDOT standards for delineation for
guardrail termini.
Medium
MassDOT
Mid-term
Medium
Lighting
Upgrade lighting at the truck ramp entrance. This should be considered in
conjunction with utility pole relocation.
Medium
MassDOT
Mid-term
High
Signage, Lighting
Consider overhead signage at the truck ramp entrance. The overhead sign
could incorporate flashing beacons and downward-facing flood lighting
Medium
MassDOT
Mid-term
Medium
Signage
Verify distance of the overall downhill grade shown on W7-1 Hill signs at
the top of the grade.
Medium
MassDOT
Short-term
Low
Driver Behavior
Construct an additional runaway truck ramp halfway down the downhill
grade.
Medium
MassDOT
Long-term
High
Signage, Driver Behavior
Provide additional signage at the “flat spot” with flashing beacons.
Medium
MassDOT
Short-term
Medium
Driver Behavior
Construct a roadside brake check area at the “flat spot”.
Medium
MassDOT
Mid-term
Medium
Driver Behavior
Consider reducing the truck advisory speed from 30 mph to 25 mph.
Medium
MassDOT
Short-term
Low
Signage
Replace all hill, grade and runaway truck ramp signage with diamond
grade high intensity yellow sheeting.
Medium
MassDOT
Short-term
Low
Signage
Install radar enhanced speed limit signs.
Medium
MassDOT
Short-term
Medium
Safety Issue
Safety Enhancement
Visibility
Visibility, Horizontal
Curvature and Load
Shifting
Visibility, Horizontal
Curvature and Load
Shifting
Page 12
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.
Appendix A. Project Team
Safety Study—Runaway Truck Ramp on Route 2 at Route 7—Williamstown, MA
Prepared by BETA Group, Inc.
Appendix B. FHWA Technical Advisory
Federal Highway Administration
TECHNICAL ADVISORY
SHOULDER AND EDGE LINE RUMBLE STRIPS
T 5040.39, Revision 1
November 7, 2011
1. P
URPOSE: To transmit updated information and guidelines for the design and installation of
shoulder and edge line rumble strips on appropriate segments of paved roads in the United
States. This information applies to a wide range of projects including new construction,
reconstruction, resurfacing, and safety improvements. Highway professionals should consider
the needs of all road users, existing roadway conditions, the scope of the project, and the
surrounding environment when applying this information and guidance.
2. C
ANCELLATION: This Technical Advisory supersedes the information contained in T 5040.35,
Roadway Shoulder Rumble Strips, dated December 20, 2001 and T5040.39, Shoulder and Edge
Line Rumble Strips dated April 22, 2011.
3. DEFINITIONS: A shoulder rumble strip is a longitudinal safety feature installed on a paved
roadway shoulder near the outside edge of the travel lane. It is made of a series of milled or
raised elements intended to alert inattentive drivers (through vibration and sound) that their
vehicles have left the travel lane. An edge line rumble strip is a special type of shoulder rumble
strip placed directly at the edge of the travel lane with the edge line pavement marking placed
through the line of rumble strips. It is sometimes referred to as an edge line rumble stripe. (See
Figure 1)
4. BACKGROUND: One of the Federal Highway Administration's primary safety goals is to reduce
the number and severity of roadway departure crashes. These consist of run-off-road (including
cross median) crashes and cross center line crashes on undivided roads. Safety improvements
proposed to address this goal include initiatives to keep vehicles on the roadway, to improve the
likelihood of a safe recovery after a roadway departure, and to reduce the severity of those
crashes that do occur. Shoulder or edge line rumble strips are one of the proven
countermeasures that reduce the risks of run-off-road crashes.
a. The target driver: Rumble strips are placed as a countermeasure for driver error, rather
than roadway deficiencies. They are designed primarily to assist distracted, drowsy, or
otherwise inattentive drivers who may unintentionally drift over the edge line. For this set
of drivers, the audible and vibratory warning produced by rumble strips greatly improves
the opportunity for a safe recovery. In a study of 1,800 run-off-road freeway crashes, one
state found that drift-off-road crashes (due to inattentive driving) resulted in death or
serious injury at a rate three to five times higher than other categories of run-off-road
crashes. Where drivers don’t safely recover, the warning created by rumble strips often
improves driver reaction, thereby reducing crash severity.
b. Early rumble strip development: Pavement surface textures and treatments to provide
audible and vibratory warning to drivers have been in use for over 50 years as a means
to alert drivers leaving the travel lane. Rolled-in strips on asphalt shoulders and formed-in
strips on concrete shoulders were two of the earlier designs used in installing shoulder
rumble strips by a number of states. A major limitation was that they had to be installed
with new pavement. There were also difficulties in consistently obtaining the desired
shape. In the 1980s, the Pennsylvania Turnpike Commission developed a milled-in
rumble strip design that could be installed on existing pavement. A series of trials led to
a preferred design of ½ inch deep and 7 inches by 16 inches, producing tire vibration and
noise with much greater alerting capacity than the rolled-in installation. Specified
dimensions could also be produced more consistently. Subsequently, many other states
began to use this milled-in design because of its effectiveness and ease of installation.
1
c. Recent history: In the 1990s, several state transportation agencies and toll road
authorities installed the milled-in shoulder rumble design pioneered in Pennsylvania,
mostly on rural freeways and expressways. In recent years, many agencies have
extended the use of rumble strips to two-lane roads because a significant portion of run­
off-road crashes occur on these roads. Some agencies have also designed and installed
narrower rumble strips where roadway widths limited the use of standard designs. The
wider use of rumble strips has also led to a great number of design modification choices
to accommodate bicyclists, who are also legal road users.
d. Striping the rumble: The practice of placing the edge line pavement markings over the
rumble strip improves nighttime marking visibility, particularly in wet conditions, by better
positioning the marking optics on the back side of each rumble, compared to limiting their
normal position within the flat marking. This practice can also increase the longevity of
the markings, particularly within the rumble, due to reduced wear from tires and added
protection from plowing activity.
5. EFFECTIVENESS: Run-off-road crashes account for approximately one-third of the deaths and
serious injuries each year on the Nation's highways. Drift-off crashes, caused by drowsy,
distracted, or otherwise inattentive driving, are a subset of run-off-road crashes. This subset
contains the specific crash types that are most likely to be reduced by shoulder or edge line
rumble strips. Many researchers have studied the effect of rumble strips on the larger set of run­
off-road data because these crashes can be easily identified in crash databases. Some studies
have addressed the more specific drift-off subset by analyzing narratives in the crash reports. In
both cases, milled rumble strips are among the most cost-effective countermeasures available for
this type of crash, since they directly address driver risk factors.
a. Run-off-road injury crashes: NCHRP Report 641 documents milled shoulder and edge
rumble strips to provide statistically significant reductions in single-vehicle run-off-road
injury crashes: 10 to 24 percent on rural freeways, and 26 to 46 percent on two-lane rural
roads. Reductions were also shown on other types of roadways, but the estimates are
not as statistically reliable.
b. Drift-off-road crashes: Studies of milled freeway shoulder rumble strips in Michigan and
New York documented drift-off-road crash reductions of 38 and 79 percent.
c. Navigational aid in bad weather: Shoulder and edge line rumble strips may also serve
as an effective means of locating the travel lane during inclement weather. Fog, snow, or
blinding rain often obscure pavement markings. The vibration provided by rumble strips
can assist drivers from unintentionally leaving the roadway in these conditions. In
addition to vibration, there are potential visibility benefits. Even a light rain can seriously
reduce the retroreflective capacity of pavement markings. When the edge line marking
is placed within the rumble strip, the vertical component will often still be visible under
these adverse conditions.
d. Noise and vibration: The common milled rumble designs have been shown to be more
effective at producing both noise and vibration, as compared to earlier designs, and are
credited with higher crash reduction factors. Design, application, and construction factors
also contribute to the effectiveness of a rumble strip installation. Further information on
these factors is discussed below.
6. A
PPLICATION CONSIDERATIONS: Edge line and shoulder rumble strips have the potential to
reduce run-off-road crashes on any paved road. A summary of rumble strip practices and
policies as of 2005 is included in NCHRP Report 641.
a. Corridor vs. spot treatment: Due to the difficulty in determining where a driver will
become distracted or drowsy, it is recommended that rumble strips be installed system­
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wide or in corridors, prioritized by the frequency of the specific crash types targeted by
the treatment. Agencies may use crash predictors such as traffic volume or trip types
(e.g. shift workers, younger drivers). Crash history will often reveal high-priority corridors,
but spot installations of rumble strips based solely on crash history are not expected to be
as effective. Within a corridor application, however, there may be spots where
discontinuing the rumble strip installation may be prudent. Some of these issues are
covered under Sections 9 and 10.
b. Urban vs. rural: While rumble strips have been extensively used in rural areas where
run-off-road crash problems exist, use on urban freeways or other roadways functionally
classified as urban is also effective. Whether the roadway is classified as rural or urban,
the use of rumbles should be determined on the merit of the cross-section and
appropriate to the context. Characteristics and concerns that often limit the usefulness or
application include low speeds, noise for adjacent residences, pavement width, presence
of curb and gutter, and significant turning movements or other conflicts of both motorists
and other road users.
c. Left vs. right: On divided highways, shoulder rumble strips should be placed on the left
shoulder as well as on the right. A comprehensive Michigan study of 1,887 drift-off
freeway crashes showed that approximately an equal percentage of vehicles involved in
crashes initially drifted to the left as to the right.
d. Combination of shoulder and center line rumble strips: The practice of installing
both center line and shoulder rumble strips along the same segments of road is
becoming more common. A Missouri study of the installation of rumble strips with wider
markings during resurfacing showed the greatest reduction in serious injury crashes were
found when both center line and edge line rumble strips were installed with the wider
markings. Some studies have shown center line rumbles cause motorists to shift vehicle
position slightly toward the shoulder. Therefore, when applying shoulder and center line
rumble strips in combination, consideration should be given to total pavement width to
determine how to best accommodate and serve all road users, particularly in no passing
zones, where drivers may be reluctant to cross the center line to pass a bicyclist (see
Section 9).
7. D
ESIGN: The design of rumble strips factor into their effectiveness. The terminology used in this
technical advisory is shown in Figure 1.
a. Types: There are four basic rumble strip designs or types: milled-in, raised, rolled-in, and
formed. Research indicates milled rumble strips produce significantly more vibration and
noise inside the vehicle than rolled rumbles. The key design parameter related to
effectiveness of the rumble strips is the dimensions, which tend to be easier to control
with milled-in rather than rolled-in or formed rumbles. Profiled markings and other forms
of raised rumble strips are sometimes used in climates where plowing is not a common
occurrence. The effectiveness of raised rumble strips has not been widely studied. They
are typically very narrow and prone to wear or displacement.
b. Dimensions: Optimum dimensions for milled rumble strips depend on operating
conditions, cross-sectional characteristics, and potential road users. Two key dimensions
that have the most effect on the alerting sound and vibration of rumble strips are depth
(D) and width longitudinal to the road (C) as shown in Figure 1. Most crash studies
referenced here evaluated shoulder or edge line rumble strips of 7 inches wide (C) by 16
inches long (B) with a depth (D) of one-half inch.
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Figure 1
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One study showed the variation in length transverse to the road (B) had the least effect
on noise produced in the vehicle compared to the other dimensions. The same study
indicated that a rumble acting on the driver side tires, such as a shoulder rumble strip
located on the inside (left) of a divided highway, produced more noise in the vehicle at
the critical driver position than rumbles on the right.
c. Location: Edge line rumble stripes or shoulder rumble strips with a narrow offset (A)
from the edge line have been shown to be most effective, because the driver is alerted
sooner and it provides a slightly larger recovery area after being alerted. This is
supported by research showing a statistically significant higher reduction in crashes on
rural freeways for rumble strips with narrow or no offset, as opposed to those with 9
inches or more offset. For rural two-lane roads, research on the impacts of narrowing the
offset distance is inconclusive. Most agencies also take the location of the pavement
joint into account to avoid cutting the strip across or immediately adjacent to the joint. In
superelevated sections where the shoulder slopes in the opposite direction from the
roadway, consideration should be given to placing the rumble strips on the superelevated
side so that the driver is warned prior to crossing the slope break.
d. Continuous vs. intermittent application: In the early days of rumble strip design,
rumbles were formed intermittently onto freshly poured concrete shoulders. Since that
time, the benefits of continuous rumble presence have been acknowledged and most
rumble applications today provide for continuous application of the rumble line, which
includes breaks only for pre-determined situations such as intersections, major driveways
and recurring bicycle gaps.
8. INSTALLATION: Offset should be measured from the edge of the travel lane, not from the
edge of the shoulder, the width of which may vary. Monitoring is necessary to ensure that
proper depth and center-to-center spacing is maintained throughout the length of the
installation.
a. Milled rumble strips: Most North American transportation agencies mill rumble strips
into their asphalt or concrete pavement. The milling operation can be performed at any
time, either in small quantity as part of a construction project, or in large quantity, taking
advantage of the economy of scale by installing rumble strips for long sections or a
number of corridors.
b. Raised rumble strips: Raised rumble strips using raised pavement markers or other
available products are sometimes used in climates where snow-plowing is not a common
occurrence. This can be useful where milling would create a concern with the pavement
integrity or where the paved shoulder is planned to be converted to a lane in the future.
c. Rolled-in rumble strips: Rolled-in rumble strips are installed during the compaction
phase. While the asphalt pavement is still hot, a steel drum roller fitted with protruding
steel bars rolls the pavement and provides indentations in the asphalt. This method
cannot attain common dimensions for milled rumbles and therefore produces less
vibration to alert drowsy drivers. Several construction difficulties have been reported with
the installation of rolled-in rumble strips, including insufficient compaction, inconsistent
dimensions, and difficulties installing patterns such as bicycle gaps.
d. Formed rumble strips: Rumble strips of similar shape and depth to milled designs have
been successfully formed into fresh portland cement concrete pavement. However, while
the formed rumbles can achieve the desired rumble shape, consistency concerns and the
limitation on installation during the paving operation remain.
e. Edge line rumble stripes: This application may be installed by milling over existing
pavement markings, which initially reduces the area of the marking visible to the motorist.
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Alternatively, some agencies install the rumble strip and new edge line at a small offset
from the existing edge line, to prevent nuisance contacts with the rumbles. In either
case, proper installation of an edge line rumble stripe includes the step of restoring the
pavement marking over the top of the rumble strips.
9. ACCOMMODATION OF ALL ROAD USERS: Safe accommodation of all road users should be
considered when designing and applying rumble strips. This includes passenger and commercial
vehicle drivers, bicyclists, pedestrians, and others. Flexibility is provided within this advisory to
address the needs of these users based on the existing and projected use in the specific corridor.
Bicyclists, in particular, are affected by rumble strips. Where shoulders are available and clear,
bicyclists will often choose to use them to avoid conflicts with faster moving vehicles in the travel
lane. However, as legal road users, they may also be in the travel lane. There are a number of
measures that should be considered to accommodate bicyclists.
a. Wide shoulders: Shoulders improve safety for all road users. Where existing crosssection exists or paved shoulders can be added within the scope of the project, it is
preferred to allow at least four feet beyond the rumble strips to the edge of the paved
shoulder. Designers should be familiar with the FHWA design guidance found at
http://www.fhwa.dot.gov/environment/bikeped/design.htm, which recommends states not
install rumbles on new construction and reconstruction projects where shoulders are
used by bicyclists unless this condition is met. Where guardrail, curb, or other continuous
obstructions exist, additional width may be needed to provide adequate clearance for
bicyclists (refer to current AASHTO bicycle guidance for additional information).
b. Bicycle gaps: Where any width paved shoulder exists beyond the rumble strip and
bicycles are allowed to ride, recurring short gaps should be designed in the continuous
rumble strip pattern to allow for ease of movement of bicyclists from one side of the
rumble to the other. A typical pattern is gaps of 10 to 12 feet between groups of the
milled-in elements at 40 to 60 feet.
c. Edge line rumble strips: Use edge line rumble strips or a smaller offset (A) where it will
allow additional shoulder area beyond the rumble strip that is usable to a bicyclist,
pedestrian or other road user. In determining the appropriate offset, designers should
consider truck traffic in the corridor and the proximity of residences, which may call for a
larger offset.
d. Adjusted rumble dimensions: (See Figure1) Decreased length transverse to the
roadway (B) of either edge line or shoulder rumble strips may provide additional space
usable to a bicyclist. Other minor adjustments in design dimensions, such as increased
center-to-center spacing (E), reduced depth (D), and reduced width longitudinal to the
roadway (C), have been shown to reduce impacts to bicyclists when they must be
traversed. Crash modification factors have not been developed for these adjustments, but
it is anticipated they will have a somewhat reduced effectiveness in alerting drivers, which
is considered a reasonable tradeoff for an agency attempting to balance the needs of all
road users.
10. MITIGATING ADVERSE EFFECTS: A balance between the safety of motorists, the potential
adverse effects on the life of the pavement, and effects on nearby residents should be considered
when installing rumble strips.
a. Maintenance: Early concerns of accelerated pavement deterioration due to installation of
milled rumble strips have proven to be unfounded. However, common practice is to
locate the rumble strips at least a few inches from joints to reduce any potential
acceleration of pavement deterioration. While rumble strips placed on pavement in good
condition will be more cost-effective by virtue of being in place longer, shoulder
deterioration is a safety issue with or without the presence of rumble strips. Experience
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has shown that traffic flow near the rumble keeps water from accumulating in the strip.
Where there are deterioration concerns, an asphalt fog seal can be placed over milled-in
strips to reduce oxidation and moisture penetration.
Recent experience in Michigan has shown that shoulder preventative maintenance
treatments such as chip seal, ultra-thin hot mix asphalt, and micro-surface, can be
compatible with rumble strips. Chip seal on top of an existing rumble strip has been
shown to retain the basic shape of the rumble, although losing some cross-section.
However, stones from the chip seal enhance the noise and vibratory properties of the
rumble. Micro-surface and ultra-thin hot mix asphalt overlays fill in existing lines of
rumble strips, but a fresh line of rumble strips can be cut into the overlay at the same
location without significant delaminating caused by the underlying filled-in rumbles.
b. Noise to nearby residents: Citizen acceptance of a state or local agency safety
countermeasure should be taken into consideration as it can affect the long-term viability
of that strategy. Although rumble strips are not intended to be traversed except when a
driver leaves the roadway, rumble strip installations may produce noise complaints where
there are nearby residences. Particularly when issues such as numbers of large
vehicles, narrow lane widths, curves, or significant passing or turning maneuvers
combine. Mitigation may include:
i. Increasing the offset (A), particularly through curves where off-tracking is
prevalent or in corridors with high volumes of truck traffic.
ii. Removal of the rumbles in the vicinity of turn lanes or in spot locations such as a
single house along a segment of roadway. The need to discontinue the use of
rumbles in spot locations should not necessarily prevent their use along a
segment or corridor.
iii. Modifying other dimensions of the rumble strip. Note that noise measurements
outside the vehicle should be used when mitigating this issue, not passenger
compartment noise measurements that are used in studies of the effectiveness in
alerting the driver.
Some surveys have shown that informed citizens often consider the improved safety
worth the nuisance noise and that residents become accustomed to the noise fairly
quickly.
11. PUBLIC INVOLVEMENT AND OUTREACH: T
ransportation agencies should follow established
procedures to involve all road users and stakeholders (including motorist associations, bicycle
organizations, enforcement agencies and emergency responders) in developing rumble strip
implementation standards and practices. This can help establish expectations for projects with
varying scopes of work and expedite project development.
When an agency is introducing edge line or shoulder rumble strips into an area for the first time or
on a large scale, they should consider public outreach to inform the general public of the safety
goals, explain how the treatment works, present historical success, and explain mitigation
measures. Proactive newspaper articles, explanatory brochures, web-based videos, agency
websites, and a variety of other outreach efforts have been used by many state DOTs and local
agencies for this purpose. The expense of removing rumble strips can be significantly higher
than the installation cost, so careful consideration of design and application along with public
involvement and outreach often provides the most efficient use of limited funds.
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12. RECOMMENDATIONS: a. Installation: On new and reconstruction projects, four feet of paved shoulder should
extend beyond the rumble strip. Continuous, milled edge line or shoulder rumble strips
should be considered:
i. System-wide on all rural freeways and other rural highways with posted or
statutory speeds of 50 mph or greater (i.e. systemic safety projects).
ii. Along rural or urban corridors where significant numbers of run-off-road crashes
that involve any form of motorist inattention have been identified (i.e. locationspecific safety improvement projects).
iii. During any highway project with a history of run-off-road crashes or where
shoulder or edge line rumble strips were overlaid during the paving process (e.g.
reconstruction or resurfacing projects).
b. Accommodation and Mitigation: To position a rumble strip program for the best
chance of public acceptance, agencies should:
i. Consider accommodation of all road users and the potential adverse side effects
mentioned in this advisory,
ii. Collaborate with stakeholders, and
iii. Modify the design and application of rumbles to the extent the agency considers
appropriate to meet the safety goal.
c. Public Involvement and Outreach: Established public involvement procedures should
be followed to ensure road user and community needs are properly addressed. When
rumble strips are being introduced on a large scale or in a new area, public outreach
should also be considered.
13. REFERENCES: The following resources are available on shoulder and edge line rumble strips.
a. Torbic, D.J. et al., Guidance for the Design and Application of Shoulder and Centerline
Rumble Strips, National Cooperative Highway Research Program Report 641, 2009.
b. Morena, David A., The Nature and Severity of Drift-Off Road Crashes on Michigan
Freeways, and the Effectiveness of Various Shoulder Rumble Strip Designs, Presented
at the 82nd Annual Meeting of the Transportation Research Board, 2003.
c. P
errillo, Kerry, The Effectiveness and Use of Continuous Shoulder Rumble Strips,
Federal Highway Administration, New York, 1998.
d. Hickey, John J. Jr., Shoulder Rumble Strip Effectiveness, Drift-Off-Road Accident
Reductions on the Pennsylvania Turnpike, Transportation Research Record 1573, 1997.
e. Sayed, T., Impact of Rumble Strips on Collision Reduction on British Columbia Highways:
A Comprehensive Before and After Safety Study, Transportation Research Record 2148,
2010.
f. Carlson, Paul J. et al., Evaluation of Wet-Weather and Contrast Pavement Marking
Applications: Final Report, Texas Transportation Institute, 2007.
g. Potts, Ingrid B.et al., Benefit-Cost Evaluation of MoDOT’s Total Striping and Delineation
Program, Midwest Research Institute, 2008.
h. Moeur, Richard C., Rumble Strip Gap Study, Final Report, Arizona DOT, 1999.
i. USDOT, Policy Statement on Bicycle and Pedestrian Accommodation Regulations and
Recommendations, 2010.
j. Elefteriadou, L., et al., Bicycle-Friendly Shoulder Rumble Strips, Pennsylvania
Transportation Institute, 2000.
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k.
American Association of State Highway and Transportation Officials (AASHTO), Guide
for the Development of Bicycle Facilities, Washington, DC, 1999.
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