Effects of different alarm timings for forward collision warning system on driver's response to true and missed alarms

Abstract

Alarm timing for a forward collision warning system may play an important role in system effectiveness. It is necessary to determine appropriate alarm timing by considering driver's response to not only true alarms but also missed alarms in order to cope with both increased system effectiveness and decreased over-reliance on the system. By using a driving simulator, two kinds of alarm timing were compared to investigate braking behaviour toward alarms and how drivers respond to missed alarms regarding different alarm timings:(1)an alarm was given based on ordinary braking behaviour for the individual; alarm timing T,(2)an alarm was given by using an particular alarm trigger logic (Stopping Distance Algorithm)as a common timing for all drivers; alarm timing S. Alarm timing S was earlier than alarm timing Tin this study. The results showed that compared to alarm timing T, alarm timing S induced earlier braking behaviour independent on degree to which an imminent collision was critical. However, effects of a missed alarm on braking behaviour may be mitigated by alarm timing T, compared to alarm timing S. Moreover, it is possible that effect of missed alarm on driver's trust may vary according to alarm timings and the number of experience of missed alarms.