A Behavioral Analysis of Running Vehicles at a Lane Reduction Section due to a Roadwork Restriction on an Expressway

Abstract

In this study, the merging behaviors of vehicles due to a roadwork lane restriction and the behaviors of vehicles that were influenced by the merging vehicles at a three-lane outbound section of Chuo Expressway were analyzed based on video images framed by plural cameras. Conflicts extracted by car brake lights and by rapid changes in vehicle running trajectories as rough criteria were classified into six categories. The occurrence processes of conflicts in the six categories were analyzed in detail by estimated the running trajectories of merging vehicles and of the vehicles they influenced at every 1/30 second. As a result, high risks were estimated to be primarily caused by delays in finding lane reductions and by insufficient communication among related drivers. A Polygon Index for Conflicts (PIC) that evaluated risks by areas composed of polygons that consisted of the point of lane reduction and the positions of related vehicles at every 1/30 second as vertexes was proposed and validated.