Drivers’ reactions to connected vehicle forward collision warnings: Leveraging real-world data from the THEA CV pilot

The Tampa Hillsborough Expressway Authority Connected Vehicle Pilot Deployment (THEA CV Pilot) implemented several vehicle-to-vehicle (V2V) and vehicle to infrastructure (V2I) applications on more than 1,000 private vehicles. This paper focuses on the Forward Collision Warning (FCW) application to study factors that are associated with drivers’ reactions to FCWs and to investigate if the observed driving styles derived from the data support the participants’ stated driving styles obtained from their survey responses. A panel of participants, driving in real-world traffic conditions for over two years with retrofitted CV technology and integrated FCW application, is used. The panel consists of a treatment (Human Machine Interface (HMI) enabled) and a control (HMI disabled) group. Random parameters logit and correlated grouped random parameter logit models are estimated to reveal possible associations between stated and observed driving behavior, HMI exposure, socio-demographic factors, and the response variable (drivers’ reaction to FCW). The study found an association between one measure of driving volatility, so that with increased driving volatility (proxy for driving aggressiveness), the probability of reaction to FCW declines. The study also found that the probability of reaction for drivers who received a warning (audiovisual) via HMI increased by 9.93 % compared to those who did not receive a warning.