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