Investigating driver uncertainty about lane change decisions

Abstract

Driver uncertainty in lane change maneuvers can induce long reaction times and lead to dangerous crashes. However, drivers’ uncertainty about their lane change decisions has not yet been targeted by researchers or vehicle manufacturers. This paper aims to investigate driver uncertainty by evaluating the variables distance gap, time-to-collision (TTC), and closing velocity between the vehicle changing lines and an oncoming vehicle. A driving simulator study was conducted with 29 participants who had to decide if, in a given traffic situation triggered by an acoustic signal, a lane change to the left would be safe. Participants’ reaction times, subjective certainty scores, and lane change decisions were recorded as indicators of driver uncertainty. The results show that the factors distance gap, TTC, and closing velocity significantly affect driver uncertainty. The analyses polynomial regression, polynomial ordinal regression, and repeated measure logistic regression were used to separately predict driver uncertainty in terms of reaction time, subjective certainty scores, and lane change decisions. The results show that all three factors are necessary for predicting driver uncertainty. The distance gap results in the strongest influence on driver uncertainty, followed by the TTC, and lastly the closing velocity. In addition, reaction times and subjective certainty scores were found to be significantly negatively correlated with each other.