On-scene Determination of Driver Crash Causation and Avoidance Maneuvers in Rear-end Collisions

Rear-end collisions are one of the most frequent crash types in the U.S. Pre-Collision System (PCS) have been developed to mitigate the frequency and severity of rear-end collisions. The potential effectiveness of these systems, however, depends on the driver’s state and their attempted avoidance maneuvers. This study utilized the National Motor Vehicle Crash Causation Survey (NMVCCS), a unique nationally representative dataset focused on crash causation, to quantify contributing factors in rear-end collisions and the avoidance maneuvers attempted by drivers of the striking vehicle. For a case to be included in NMVCSS, the crash site had to be visited by an investigator prior to the scene being cleared. Rear-end collisions were more likely to involve a driver that was following too closely, inattentive, distracted by a non-driving activity, focusing on external factors, exhibiting inadequate surveillance, and making false assumptions of other drivers’ actions compared to other frontal collisions. Compared to other frontal collisions, rear-end collisions were more likely to have occurred on roadways with traffic flow restrictions, speed limits at highway speeds, multiple lanes, and relation to a junction (e.g. intersections, on-ramps, merging zones). In 72% of rear-end collision the driver attempted an avoidance maneuver. Of those drivers attempting an avoidance maneuver, 67% only applied the brakes, 27% applied the brakes with steering, and 6% only steered. Conversing and non-driving activities were found to be significant factors indicating the lack of an avoidance maneuver in rear-end collisions. In all rear-end collisions, Forward Collision Warning and Pre-Crash Brake Assist could be potentially effective in 84% of crashes, while Autonomous Braking could be effective in 90% of crashes.