Lane Utilization Analysis of Drivers to Examine Safety on a Two-Lane Road with Horizontal Curve and Longitudinal Slope

Abstract

Horizontal curves are one of the road sections with a high potential for accidents at high speeds. In such a section of road, vehicles may be subjected to high centrifugal forces due to the horizontal curve and the high vertical downhill slope. Thus, vehicles often tend to drift out of their lane. In this case, the lane utilisation level of drivers within the small radius curve can vary and the lane keeping level may become. Low lane keeping by vehicles leads to traffic accidents caused by vehicles colliding sideways. This study quantitatively investigates the lane selection and utilization behaviour of drivers where such a problem is observed. Software has been developed to determine the lateral wheel positions (right-left) and the gravity centre positions of the vehicles on the lanes where there is both a small horizontal curve with a small radius and a vertical downhill slope. A total of 279 (84.5%) vehicles were observed to have different levels of lane keeping discipline. In addition, a total of 51 (15.5%) vehicles had no lane keeping discipline. It was also found that cars and vans in light vehicle status use Lane-1 more often in order to be less exposed to the skidding effect in the horizontal curve. It has been observed that the lane keeping of many vehicles moves away from the ideal situation due to the centrifugal force effect caused by the horizontal curve, and as a result they continue their movements by using both lanes.