Method to Optimise the Position of Rumble Strips on the Hard Shoulder to Avoid Run-off-road Accidents and Unnecessary Noise Pollution

Abstract

Around one third of road deaths in Europe are the result of run-off-road accidents. The major causes are considered to be fatigue, distraction and inattention. Rumble strips are one of the appropriate available measures that help prevent run-off-road accidents. When driving on the near right side of the road, it is possible to drive over the rumble strips unintentionally. Studies have shown that one percent even drive on the emergency lane or hard shoulder. With an average daily traffic of 33,000 vehicles, this causes unnecessary additional noise pollution. The study at hand describes a method that introduces a different positioning of rumble strips as a means of reducing unintentional crossing and run-off-road accidents. Based on speed and angle of exit as well as the friction between tyre and traffic lane and an assumed reaction time, the lateral distance needed could be determined. The assumption is that the driver's reaction is a sole steering movement back onto the traffic lane, where the vehicle traverses a circular path at the maximum possible speed. At a median-speed of exit of 110km/h with a median-angle of exit of 5.5° from real accidents, a lateral distance of 2.0 m would be needed on wet road surfaces. The reaction time after driving over the rumble strip was considered to be 0.5 s.