Effect of request-to-intervene timing during automated driving at nighttime on driving behavior

Abstract

In this research, we investigated the effect of allowance time on driver behavior when the Request-To-Intervene (RTI) at nighttime driving. We also analyzed driver behavior at RTI using the concepts of Situation Awareness (SA) and the behavioral analysis description method. The experiment was performed using a driving simulator, and a RTI occurs when the subjects was driving using level 3 of automated driving at night. After that, the subjects operate the steering wheel to avoid obstacles. As a result of the experiment, the lighting area of the driving beam was limited at night, so the obstacles moved out of the lighting area when Time-To-Collision (TTC) exceeded 7 seconds. Therefore, the driver was unable to responds to RTI driving behavior because no obstacles were detected. On the other hand, it was found that if TTC is shorter than 5 seconds, there is a high possibility of inducing a sudden operation the driver, and there is not enough time to confirm driving safety, so we think this driving condition is not suitable for RTI timing. Therefore, we think 7 seconds is enough for RTI timing at night. If this timing is secured, safety operation to avoid the collision to the obstacle is possible.