ABSTRACT：Forward collision warning (FCW) systems function by alerting drivers to upcoming hazards ahead and have been shown to help drivers respond more quickly under emergency situations. As FCW directly affects how vehicles interact longitudinally with one another, it may also influence car-following behavior such as reaction time, which has been little researched. To investigate these effects, driving data were collected from the Shanghai Naturalistic Driving Study. Five data-collecting vehicles were equipped with Mobileye® systems, which included an FCW function with headway display and warning system. Participants drove the vehicles for two months, with the Mobileye® system activated the second month only. From the 161,055 km of naturalistic driving data collected from 60 drivers, 3,000 car-following events were selected, and the effects of FCW on car-following headway and reaction time, and on the parameter values of the Gazis-Herman-Rothery (GHR) model were examined. Results showed that (1) drivers tended to maintain shorter headway with FCW enabled, while the proportion of time in short headways did not increase; (2) FCW reduced car-following reaction time when the lead vehicle was accelerating and when the relative speed between the lead and following vehicle was large; and (3) a reduction in the space headway exponent of the GHR was observed when FCW was enabled, indicating that drivers follow more closely with FCW because the system increases drivers’ sensitivity to changes in following gaps. Results of this study suggest that an FCW system with a headway monitoring function may increase traffic efficiency and stability without degrading safety.
Meixin Zhu, Xuesong Wang, Impact on Car Following Behavior of a Forward Collision Warning System with Headway Monitoring, Transportation Research Part C: Emerging Technologies, Volume 111, February 2020, Pages 226-244.