Effects of lead vehicle speed and separation distance on driver car-following behavior

A car-following experiment was conducted to investigate the effects of lead vehicle speed and separation distance on driver car-following behavior. Furthermore, the influence of a driver support system with haptic gas pedal feedback was investigated as well. The experiment was set up such that system identification techniques could be applied using a quasi-linear multi-loop car-following model. It was assumed that car-following is a compensatory task in which errors in relative velocity and relative distance are minimized. Results of the experiment show that drivers mainly use relative velocity for their control task. Low crossover frequencies and high phase margins indicate that car-following is a relatively simple and robust task, which is difficult to improve on when drivers can make full use of visual feedback.