Evaluating the effects of the number of exit lanes on the diverging driver performance

This study investigated the driving performance of drivers exiting from the highway under various geometric deceleration lane conditions. Specifically, the effects of different deceleration lanes on the speeds, trajectories, and decelerations of diverging drivers were investigated to increase the knowledge of driver behavior while approaching a highway exit, during the lane-change maneuver, and along the deceleration lane. Thirty-one drivers took part in the experiments. Two different tapered deceleration lanes (with a single-lane exit ramp and with a two-lane exit ramp, respectively) were implemented using a driving simulator to observe how exiting drivers performed, by analyzing their speeds, decelerations, and trajectories. The main results demonstrated that, for the geometric and operating conditions investigated in this study, a single-lane exit ramp resulted in a poorer performance from the exiting drivers with regard to the operating and safe driving conditions. In fact, it was found that, when a single-lane exit ramp was available, drivers adopted lower exiting speeds and higher decelerations than those using a two-lane exit ramp. Therefore, the latter seemed to provide improved performance, by limiting the interferences of the diverging drivers with through traffic.