Effects on Driver Speeds of In-Lane Rumble Strips on Approaches to ...

CONCLUSIONS
An analysis of the speed data collected at the study sites reveals small changes in mean and 85 th
percentile speed on approaches with rumble strips. In some cases the change was an increase in
speeds and at other sites the change was a decrease in speeds on the approach to the intersection.
Generally, the speed changes were less than 4 mph (6.4 km/h), with most being on the order of 1
to 2 mph (1.6 to 3.2 km/h). Statistical tests revealed that many, but not all, differences in mean
speeds at each site were statistically significant at the 95 th percent level of confidence.
An analysis was performed on a subset of five sites that had similar rumble strip installations.
The speed data were consolidated using the first rumble strip that a driver would encounter as the
common point between the five sites. For each location along the speed profile with a difference
in speed greater than 1.0 mph (1.6 km/h), which is the limit of the speed measuring equipment,
speeds were lower in the after period. The decrease in speeds ranged from 1.4 to 5.0 mph (2.3 to
8.0 km/h). The statistical test found that all differences in mean speeds were statistically
significant for the speed profile.
ACKNOWLEDGEMENTS
The research described in this paper was performed by the Texas Transportation Institute as part
of a research project sponsored by the Texas Department of Transportation (Project Number 0-
4278: Safety Measures for Rural Intersections). The contents of this paper reflect the views of
the authors, who are responsible for the facts and accuracy of the data presented herein. The
contents do not necessarily reflect the official views or policies of the Texas Department of
Transportation.
REFERENCES
1 Walton, S., and E. Meyer. “The Effect of Rumble Strip Configuration on Sound and
Vibration Levels.” ITE Journal, December 2002. pp. 28-32.
2 Zaidel, D., A.S. Hakkert, and R. Barkan. “Rumble Strips and Paint Stripes at a Rural
Intersection.” Transportation Research Record 1069, Transportation Research Board,
National Research Council, Washington D.C., September 1986. pp. 7-13.
3 Harwood, D.W. “Use of Rumble Strips to Enhance Safety.” Synthesis of Highway Practice
191, National Cooperative Highway Research Program, National Academy Press,
Washington, D.C., 1993.