Driver Distraction and Reliance: Adaptive Cruise Control in the Context of Sensor Reliability and Algorithm Limits

This study investigated how system failures influenced drivers’reliance on Adaptive Cruise Control (ACC). A medium-fidelity driving simulatorwas used to evaluate the effect of driving condition (traffic, rain) and automation(manual control, ACC) on headway maintenance and brake response. Inconditions of rain, the signal continuity of the ACC sensors was degraded and inconditions of heavy traffic, the braking limits of the ACC system were exceeded.Dependent variables included response time to lead vehicle (LV) braking, numberof collisions, and both time headway (THW) and time-to-collision (TTC) atinstant of the brake response. Throughout the drive, a continuous (forced-paced)secondary task was introduced to determine how an in-vehicle task interactedwith ACC reliance. Results showed that the failure type influenced driver’sreliance on ACC with drivers relying more on ACC in traffic periods than in rainperiods. ACC appeared to offer a safety benefit when drivers were distracted withcomplex mental tasks in periods of heavy traffic.