Towards an understanding of adaptive cruise control

Adaptive cruise control (ACC provides assistance to the driver in the task of longitudinal control of their vehicle during motorway driving. The syste m controls the accelerator, engine powertrain and vehicle brakes to maintai n a desired time-gap to the vehicle ahead. This research describes the resu lts of a detailed microscopic simulation investigation into the potential i mpacts of ACC on motorway driving. In addition to simulation, real vehicle driving profiles, obtained from instrumented vehicle experiments in three E uropean countries, have been used to compare real following behaviour with that of a simulated ACC equipped vehicle. This new approach has shown that following with an ACC system can provide considerable reductions in the var iation of acceleration compared to manual driving. This indicates a potenti al comfort gain for the driver and environmental benefits. A number of crit ical situations in which ACC does not perform well have also been identifie d. The research also highlights the limitations of microscopic simulation i n modelling the impacts of ACC because of the lack of understanding of the interaction between the driver and the ACC system relative to the traffic c onditions. (C) 2000 Elsevier Science Ltd. All rights reserved.