This report describes the results of studies on the use and effectiveness of rumble strips, including a survey of Minnesota county engineers and a simulation conducted at the University of Minnesota Human Factors Laboratory. Sixty-eight of 87 counties responded to the survey. Of the 68 respondents, 56 install in-lane rumble strips. The survey also asked respondents to describe the guidelines that they used to designate areas for rumble strip installation. As part of the simulation study, test subjects drove in a simulator through a designed experiment to measure the effectiveness of in-lane rumble strips. The results of this study showed different braking patterns between intersections with in-lane rumble strips and those without rumble strips. Those with rumble strips braked earlier and harder. The report recommends that shoulder rumble strips be used in areas with high rates of run-off road crashes. Before-and-after studies have shown conclusively that shoulder rumble strips have reduced run-off road crashes by 20% to 72%. It also recommends a follow-up study on in-lane rumble strips involving drivers that are sleep deprived, under the influence of alcohol, or driving in poor conditions. (Author/publisher)
Samenvatting