Vehicle Kinematics and Deceleration Rates of Four Staged SUV Rollovers

The purpose of this study was to characterize the kinematics of four Chevrolet Tracker rollover tests and to determine their average and intermediate deceleration rates while traveling on concrete and dirt. Single vehicle rollover tests were performed using four 2001 Chevrolet Trackers fitted with six degree of freedom kinematic sensors. Tests were conducted using a rollover test device (RTD) in accordance with SAE J2114. The test dolly was modified (resting height of the vehicle wheels was raised) between tests 1, 2, and 3. The RTD was accelerated to 15.6 m/s (35 mph) and then decelerated rapidly by an energy absorbing crash cushion (EA) to cause the vehicle to launch and roll. The vehicles initially rolled on a smooth concrete surface and continued into loose dirt.

This paper adds to the body of work identifying phases of constant deceleration during staged RTD tests and compares these phases to the overall deceleration rate. Across all tests, the average deceleration rate from launch to rest was 0.32g (range 0.31g to 0.36g). On concrete, the average deceleration rate was 0.23g (range 0.20g to 0.25g), and on dirt the average deceleration rate was 0.56g (range 0.37g to 0.66g). The dolly modifications minimized the interaction between the vehicle and the EA that caused vehicle 1 to yaw. These modifications changed the vehicle roll kinematics and initial roll rates, but did not affect the deceleration rates.