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This study examines through computer simulation the vehicle dynamics regime of vehicle entry into a travel lane via traversal of a vertical change in pavement elevation. A three-dimensional vehicle dynamics software package is used to model a vehicle as a six degree-of-freedom sprung mass with up to five degrees-of-freedom for each unsprung mass for each axle. The parameters of the simulator’s radial and sidewall tire force models are determined through correlation with full-scale vehicle traversal tests. The correlation parameters include vehicle speed, heading, yaw rate and lateral acceleration. The simulation is first calibrated by successfully modeling vehicle traversal of a pavement edge at shallow angles.

A commercially-available two-dimensional software program, validated to model high speed collisions, was extended to analyze rear-end collisions involving speed changes below 10 miles per hour. Simulation results were compared to the results of several series of published full-scale staged collisions. A total of 84 rear-end crash tests, involving 20 vehicles of different makes and models, were analyzed. Test conditions included free-rolling as well as braked vehicles, and in-line as well as oblique collision configurations. The analysis demonstrates that the simulation model provides accurate and reliable predictions of vehicle delta-V's for rear-end collisions, under aligned and oblique conditions, and with free-rolling and braked conditions for the foam core and piston-equipped bumper types examined.