Several previous research efforts have demonstrated that
rumble strips reduce single vehicle run-off-road crashes which are the target
crashes for that treatment. However, recent research by Wu et al. (2014)
indicates that shoulder rumble strip installation has no effect on reducing the
probability of the most severe crashes. These researchers examined the effect
of rumble strip presence on fatal and major injury crashes of all types (i.e., target
plus non-target). A similar trend is found in the freeway predictive method in
Chapter 18 of the Highway Safety Manual. When shoulder rumble strips are present,
this method predicts a significant reduction in fatal-and-injury crash
frequency as a group, but it also predicts a shift in the severity distribution
such that there is a slight increase in fatal and major injury crash frequency.
Based on these recent findings, the following questions are
being asked, “Have the previous studies
overlooked the secondary influence of rumble strips on the non-target crash
types”? Is it possible that rumble strip installation increases the frequency
of the most severe non-target crashes to the extent that it offsets the
well-documented reduction in severe target crash frequency”? Research is needed
to examine these questions.
Research by Torbic et al. (2009) indicates that
shoulder rumble strip effectiveness varies by facility type (i.e., freeway,
multilane highway, two-lane highway) and by area type (i.e., rural, urban);
possibly reflecting an indirect effect of speed or roadway lighting presence on
rumble strip performance. This same
research also indicates that rumble strip effect may vary among states;
possibly reflecting an indirect effect of rumble strip design (i.e.,
milled/rolled and offset from traveled way) on rumble strip performance. The findings from other recent research
suggest that shoulder rumble strip effect may vary by alignment location (i.e.,
curve vs. tangent). It is possible that
the recent research findings regarding target-vs-non-target-crashes might be
explained by the characteristics of the sites studied and the associated
differences in rumble strip design. A
research project is needed to identify the factors that influence rumble strip
safety effect to ensure that agencies are informed of rumble strip designs that
are most effective at improving overall safety.
The objectives of this research are to (1) quantify the effect
of shoulder rumble strip presence on both target and non-target crashes at each
individual severity level (i.e., fatal, incapacitating injury,
non-incapacitating injury, possible injury, and property damage only) and (2)
develop models for predicting rumble strip effect as a function of site
characteristics such as (but not limited to) facility type, area type, rumble
strip design, and alignment location. As
a minimum, this research should address freeway facilities given that this
facility type has the highest VMT and, thereby, the most potential to benefit
from the research results. However, other facility types should also be
investigated if possible. The research plan to accomplish these objectives will
likely need to include the following activities:
· Identify alternative shoulder rumble strip
designs used throughout the U.S.
· Evaluate the impact of shoulder rumble strip
presence on target and non-target crashes at each severity level; examine
whether the magnitude of the effect is influenced by facility type, area type,
rumble strip design, and alignment location
· Develop models for predicting rumble strip
effect on crash frequency and severity as a function of influential site
characteristics; the models may be represented as crash modification functions
· Recommend best practice for installation of shoulder
· Document the proposed predictive models in a
format suitable for incorporation in the next edition of the Highway Safety Manual
· Wu, F., E. Donnell, and J. Aguero-Valverde. “Relating Crash Frequency and Severity: Evaluating the Effectiveness of Shoulder Rumble Strips on Reducing Fatal and Major Injury Crashes.” Accident Analysis and Prevention, Vol. 67, 2014, pp. 86-95.
· FHWA Technical Advisory T 5040.39: Shoulder and Edge Line Rumble Strips, November 7, 2011.
· Torbic, D.J. et al, NCHRP Report 641: Guidance for the Design and Application of Shoulder and Centerline Rumble Strips. National Cooperative Highway Research Program 2009.
· 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.
· Perrillo, Kerry, The Effectiveness and Use of Continuous Shoulder Rumble Strips, Federal Highway Administration, New York, 1998.
· Hickey, John J. Jr., Shoulder Rumble Strip Effectiveness, Drift-Off-Road Accident Reductions on the Pennsylvania Turnpike, Transportation Research Record 1573, 1997.
· 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.
· Carlson, Paul J. et al, Evaluation of Wet-Weather and Contrast Pavement Marking Applications: Final Report, Texas Transportation Institute, 2007.
· Potts, Ingrid B.et al, Benefit-Cost Evaluation of MoDOT's Total Striping and Delineation Program, Midwest Research Institute, 2008.
· Moeur, Richard C., Rumble Strip Gap Study, Final Report, Arizona DOT, 1999.
· USDOT, Policy Statement on Bicycle and Pedestrian Accommodation Regulations and Recommendations, 2010.
· Elefteriadou, L., et al, Bicycle-Friendly Shoulder Rumble Strips, Pennsylvania Transportation Institute, 2000.
· American Association of State Highway and Transportation Officials (AASHTO), Guide for the Development of Bicycle Facilities, Washington, DC, 1999.