Investigation of Speeding and Centerline Encroachment by Motorcycle Riders on a 2-lane Rural Road

Abstract

Motorcycle riders are considered as one of the most vulnerable road users group worldwide. This is supported by numerous statistics which reveal that despite the reduction of vehicular fatalities over the last 15 years, the lesser improvement is observed in motorcycle fatal accidents compared to the other road users, either vulnerable or not. Speed and lane departure have been documented as significant contributory factors which precipitate the occurrence of motorcycle accidents. Many researchers attempted to identify and analyze the reasons behind this fact by conducting naturalistic riding studies using instrumented motorcycles and a relatively small number of volunteers. The recent development of multifunctional GPS devices of high positional and speed accuracy has assisted in this direction by allowing the planning of field measurements in a cost and time-effective manner. A similar practice has been adopted to the present study which aims to record and process the recorded data of a mid-scale naturalistic riding study in a two-lane rural road segment in an effort to investigate whether the motorcycle riders follow the posted speed limits. Apart from the investigation of the traveling speed, the high accuracy of the recorded positional data permitted us to compare the trajectory of the riders with the one that is determined by the theoretical model. The latter assumes that the road users travel along the midline of the travel lane and hence the curvature of the horizontal alignment coincides with the actual trajectories. The findings of the paper reveal that the riders do not comply with the posted speed limits to a large extent and follow a trajectory different from the theoretical one. Both findings pose a great risk to motorcycle riders’ safety, which strengthening is the main contribution of the present paper.