Rollover and Near-Rollover Kinematics During Evasive Steer Maneuvers

Vehicle rollovers are complex events that can be difficult to reconstruct. The goal of this study was to explore whether different vehicle trip models could identify when during the trip phase a vehicle possesses the dynamic conditions needed to rollover. We used three sport utility vehicles (SUVs) with either absent or disabled electronic stability control to conduct six tests involving a steer-induced control loss on a large flat concrete surface. Vehicle kinematics were measured using a GPS speed sensor, tri-axial accelerometers, tri-axial angular rate sensors, and both drone- and land-based video cameras. Four vehicle trip metrics were derived and evaluated using the vehicle dynamics between steer onset and the end of the trip phase. During three tests, one or more of the vehicle’s tires lifted off the ground but the vehicle did not roll. In the other three tests, the vehicle rolled. All four metrics showed differences between the non-rollover and rollover tests, with one metric indicating that the dynamic conditions for rollover were present between 0.36 s and 0.78 s before the end of the trip phase. With further refinement, testing and validation over a wider range of vehicles and conditions, these metrics could be useful in some rollover reconstructions for identifying when sufficient dynamic conditions are present during the trip phase for rollover to occur.