Forward collision warning systems that alert drivers when a rear-end crash is imminent, and automatic emergency braking systems that apply the brakes when drivers do not intervene, are effective countermeasures to prevent rear-end crashes. This study examined the effectiveness of forward collision alert (a forward collision warning system) and front automatic braking (an automatic emergency braking system) on rear-end striking crashes among vehicles from an original equipment manufacturer (OEM). Crash and exposure data from a variety of U.S. states were also used in this study to develop a regression model to understand the effectiveness of the technologies in reducing the crashes with various severity levels.
The study utilized vehicles from a total of 27 different vehicle makes with model years ranging between 2013 to 2015 that each offered front automatic braking with forward collision alert or forward collision alert alone as optional features. Forward collision alert can use a camera, radar, or both types of sensors to detect leading vehicles. Vehicles that use radar or both camera- and radar-sensing for the forward collision alert system are also equipped with both front automatic braking and adaptive cruise control systems. The presence of any other optional collision avoidance features was controlled for in the analyses. Police-reported crash data from 2012 to 2016 that included Vehicle Identification Numbers (VIN) were obtained from 23 states for the study. A Poisson regression was used to compare involvement rates in rear-end striking crashes of all severities, with any injuries, and with injuries in other vehicles (third-party injuries) between vehicles with front automatic braking and forward collision alert, with forward collision alert alone, and with the same vehicle models where the optional systems were not purchased, controlling for other factors that may contribute to crash risk.