Classifying driver´s uncertainty about the distance gap at lane changing for developing trustworthy assistance systems

Driver´s uncertainty in lane change situations could cause longer reaction times and even lead to wrong decisions, which is very dangerous for the critical driving task. We assume that reducing driver´s uncertainty with assistance systems in lane change situations can not only increase traffic safety, but also increase driver´s trust in assistance systems. In order to develop trustworthy assistance systems, this paper starts from classifying driver´s uncertainty about distance gaps and studies the impact of distance gaps on driver´s uncertainty at lane changing. In the driving simulator experiment, participants were asked to take steering or brake actions in different lane change situations. Their reaction times to an acoustic signal ordering to start changing lanes and subjective certainty scores were collected and analyzed. The results showed that with the constant closing speed of 10 km/h between the ego vehicle and rear vehicle, the brake action was more often preferred than the steering and participants were relatively certain with short reaction times at small distance gaps (<; 32m). At large distance gaps (> 44m), the steering was more often chosen than brake actions and participants were also certain with short reaction times. However, when the distance gap was in between (32m, 36m, 40m, 44m), participants were very uncertain and had relatively long reaction times.