The Transport Accident Commission (TAC) SafeCar study evaluated the impact of three Intelligent Transport System technologies, alone and in combination, on driver performance: Following Distance Warning; Intelligent SpeedAdaptation; and a Seatbelt Reminder. Each test vehicle or "SafeCar" was also equipped with Daytime Running Lights and a Reverse Collision Warning system. Twenty-three fleet car drivers each drove a SafeCar for 16,500 kilometers. This article focuses on the impact on driving performance, mental workload and driver acceptability of the Following Distance Warning system. The results revealed that the Following Distance Warning system had a positive effect on drivers' following behavior, with use of the system significantly increasing mean time gap between the SafeCars and lead vehicles in several speed zones and reducing time gap variability in one speed zone.The system was rated as acceptable by the drivers and did not increase subjective mental workload. However, most drivers did report an increase in frustration when using the system, brought about by the occasional issuingof nuisance warnings. (Author/publisher)
Abstract