In an effort to reduce lane-departure crashes, in 2008 the Michigan Department of Transportation (MDOT) began a three-year statewide non-freeway rumble strip installation initiative. This initiative called for the installation of milled centerline rumble strips on all rural non-freeway highways with a posted speed limit of 55 mph and a paved roadway width greater than 20 ft and shoulder rumble strips on roadways with paved shoulders that were at least 6 ft wide. Approximately 5,400 miles of non-freeway roadways were ultimately included in this rumble strip installation initiative. As this initiative was believed to be the largest of its kind in the United States at the time, it was important for MDOT to evaluate the impacts associated with the rumble strip installations to provide guidance for future implementation both within Michigan and other states. The objectives of this study included : Identification and analysis of 'Before' traffic crashes ; Assessment of impact of rumble strips on driver behavior, bicyclist safety, roadside noise, and short-term pavement performance. Several field data collection efforts were undertaken in order to accomplish the objectives. Based on the results of the evaluation, it is concluded that rumble strips on high-speed non-freeway highways improves driver performance on most highways and traffic scenarios. Vehicles produced higher levels of roadside noise when traveling over the rumble strips compared to normal passbys. The rumble strip noise typically did not exceed the roadside noise level produced by tractor trailer trucks traveling on normal highways. Finally, centerline rumble strips did not contribute to short-term transverse cracking are in asphalt pavements. Three years of 'Before' crash data were analyzed to identify the target crashes that is expected to be alleviated by the installation of centerline rumble strips on MDOT’s high-speed trunkline (non-freeway) system. (Author/publisher)
Samenvatting