Bicycle-friendly shoulder rumble strips

Highway shoulder rumble strips have proven to be an effective measure in reducing run-off-the-road (ROR) crashes on urban and rural freeways. ROR crashes may be reduced by as much as 20 to 50% when rumble strips are installed. As the use of shoulder rumble strips is extended to non-freeway facilities, bicyclists will encounter rumble strips more frequently in the future. Bicyclists are concerned about manoeuverability problems while traversing rumble strips because they can be very uncomfortable to ride over and may cause loss of control of the bicycle. This research was initiated to develop new rumble strip configurations that could alert inattentive/drowsy motorists and be safely and comfortably traversed by bicyclists. Thus, the objective of this project was to develop new rumble strip configurations that decrease the level of vibration experienced by bicyclists when traversing rumble strips, while at the same time, provide an adequate amount of stimuli to alert inattentive/drowsy motorists. Three primary steps were involved in the development of the new rumble strip configurations. The first step was to develop, evaluate, and rank different configurations for their potential to be "bicycle-friendly" yet, at the same time, not degrading the alerting properties for drivers in motor vehicles. A simulation model was developed and validated to evaluate various new designs. The second step was to install several of the recommended configurations that had the greatest potential to be "bicycle-friendly" and conduct field experiments to further evaluate their effectiveness. The final step was to analyse the data and rank the configurations that were installed, based on their ability to provide a comfortable and controllable ride for bicyclists and to alert inattentive/drowsy motorists. Based on the results of the bicycle testing and the motor vehicle testing, two new "bicycle-friendly" rumble patterns are recommended for implementation along non-freeway facilities.