Behavioral Adaptation to Adaptive Cruise Control

Abstract

The ability of adaptive cruise control (ACC) to induce behavioral adaptation in drivers was assessed in a test-track environment. Eighteen experienced drivers performed a secondary, in-vehicle number search task while following a confederate lead vehicle. The three counterbalanced conditions were: No ACC (self-maintained average headway of 2 s), ACC-Short (headway of 1.4 s) and ACC-Long (headway of 2.4 s). Results indicate that ACC can induce behavioral adaptation in potentially safety-critical ways. Participants were able to correctly identify significantly more stock price quotes per minute when using ACC than when they drove unaided. At the same time, participants reacted more slowly to a safety-relevant brake light detection task when they used ACC, and responded within a safe time margin 33% less often. This effect was particularly pronounced in those scoring high on a sensation-seeking scale. ACC use was associated with impaired lane-keeping performance, an effect that was also more evident in high sensation-seekers. During a simulated failure of the ACC system, participants waited until the vehicle-to-vehicle headway was 0.6 s before they intervened; those with an external locus of control took longer to react than those with an internal locus of control. Finally, participants' trust in ACC increased following exposure, and was not affected by the failure of the ACC system. Results are consistent with similar research conducted on lane departure warning systems.