About the research
As a low-cost countermeasure to rural intersection crashes, transverse rumble strips (TRS) provide an audible and tactile warning to drivers approaching an intersection with the primary goal of decreasing crashes that result from running a stop sign. The objective of this project is to evaluate the effectiveness of different TRS patterns on stopping behavior at rural stop-controlled intersections.
Eight rural intersections in St. Louis County, Minnesota, were selected as test sites. Milled-in rumble strips were installed at the sites that varied in terms of number of panels (2 or 3) and number of rumble strips per panel (6 or 12). Speed, traffic volume, and video data were collected at each site before, 1 month after, and 9 months after TRS installation to evaluate various crash surrogate metrics. The most significant metrics affected by TRS configuration included percentage of vehicles engaging in a full/rolling stop at the intersection, change in average speeds on the approach near the intersection, percent of vehicles traveling 45 mph or more, and percent of vehicles engaging in late braking. A qualitative summary of the various metrics suggested that the 3-panel, 12-rumble strip design performed the best.
Noise analyses were also conducted to assess whether the number of rumble strips per panel (6 or 12) affected exterior and in-vehicle noise. No significant differences in exterior noise were found, and both panels produced sufficient in-vehicle noise to alert a drowsy driver. As a result, noise was not a factor in selecting one panel type over another.