Experimental Evidence on Car-Following Behavior

This paper aims to assess follow-the-leader dynamics from recorded trajectories. A parsimonious method is proposed to study car-following (CF) behavior without any specific assumption on the CF rule. Since most of CF model assume that drivers react to a front stimulus with a time lag T(r), the method is based on this single property. The method analyzes the difference in position of a vehicle at time t with its follower at time t+T(r): histograms of such measurements shed light on congested driving behavior. This method is performed on I-80 Next-Generation Simulation (NGSim) dataset and reveals important features about CF behavior in congestion. The method clearly shows that most of vehicles (74% of the studied sample) follow their leader with a uniform time and space lag along the experimental site. It also shows that 8% of drivers change their CF behavior along the experimental site. Finally, difference in position does not explain follow-the-leader dynamics of the remaining 18% of vehicles.