This study set out to examine the following diverse questions regarding cooperative adaptive cruise control (CACC) use: * Does CACC reduce driver workload relative to manual gap control? * Does CACC increase the probability of driver distraction relative to manual gap control? * Does CACC result in reduced driver arousal relative to manual gap control? * Does CACC result increase the ability to avoid a crash when exposed to an extreme breaking event? * Will drivers trust the CACC system? These questions were addressed in an experiment conducted in the Federal Highway Administration Highway Driving Simulator. A total of 49 licensed drivers were tested, with 12 or 13 participants in each of 4 groups. All of the groups drove in the third position in a five-vehicle platoon in which all of the other vehicles were equipped with simulated CACC. The groups differed as to whether the participant vehicle was equipped with CACC and the type of event at the end of the drive that disturbed the longitudinal spacing of the platoon. As assessed by the National Aeronautics and Space Administration Task Load Index, the CACC system did reduce perceived driver workload relative to driving without cruise control. CACC users appeared slightly more likely to engage in diversionary activities (e.g., listening to the car radio) than control group drivers. CACC yielded a substantial and statistically reliable reduction in the probability of a crash. No evidence was obtained to suggest that use of CACC leads to lower levels of driver arousal than manual gap control. Participants showed a great deal of trust in the CACC system. In a situation where all of the control participants used the brake to maintain a comfortable gap, only 2 of 36 CACC users overrode the system with the brake or accelerator. (Author/publisher)
Abstract