The computer program PC-CrashTM was used to support the reconstruction of 26 documented rollover collisions involving sport utility vehicles, and the resulting angular velocity profiles were analyzed across several categories of situational conditions and domains to identify trends. The locations of peak angular velocities were plotted within the time and roll number domains.
It was found that angular acceleration periods are, on average, shorter in terms of time than the angular deceleration periods over the duration of most rollover reconstructions. Peak angular velocity was usually found to occur within the second quarter of the time span of the event, and also within the second quarter of the total number of rolls, across a range of roll surface conditions involving both onroad and off-road roll initiation and rollout.
Given the limiting conditions imposed on the selection of rollovers for inclusion in the sample set, the average peak roll rate was found to occur at approximately 42 percent of the total time duration of the event, and at approximately 35 percent of the total number of roll quarters experienced by the vehicle.
All cases were reconstructed by hand using conventional evidentiary and analytical techniques, and a PC-Crash simulation was developed for each to validate the conclusions of the reconstruction. This survey was restricted to “untripped,” frictioninduced rollovers, and most involved roll initiation at highway speed. Both on-road and off-road roll initiations were included in the survey, though documented cases of off-road roll initiation due to a furrow trip mechanism were excluded.