Evaluation of Safety Effects of Driver Assistance Systems Through Traffic Simulation

Road safety is a major concern in all countries, and large efforts are constantly dedicated to create safer traffic environments. Today increasing attention is turned toward active safety improving countermeasures that improve road safety by reducing accident risks. Such active countermeasures include advanced driver assistance systems (ADAS). To ensure that these new applications result in real safety improvements, a priori estimations of safety effects are needed. This paper considers estimation of the safety effects of ADAS through traffic simulation. Requirements imposed on a traffic simulation model to be used for ADAS evaluation are presented, and a car-following model to be used in simulations that include ADAS-equipped vehicles is proposed. ADAS have an impact on traffic through the functionalities of ADAS and through changes in driver behavior for ADAS-equipped vehicles. Driver behavior for ADAS-equipped vehicles has usually not been considered in previous simulation studies, including those for ADAS-equipped vehicles. Simulation runs of rural road traffic that used the proposed car-following model did, however, indicate that behavioral changes caused by the ADAS were important factors for the safety impact. Modeling of the behavior of drivers in ADAS-equipped vehicles is therefore essential for reliable conclusions on the road safety effects of ADAS.