Residual or static vehicle crush profiles are routinely used to reconstruct a collision with impact models that assume an impulse exchange at peak vehicle deformation rather than at residual deformation. Here we assess the effect of using residual crush versus dynamic crush on impact speeds with a Monte Carlo analysis of the PC-Crash impact model. Random two-vehicle collisions using peak dynamic crush were first simulated to rest. Maximum vehicle engagements were then adjusted to simulate a corresponding static crush level and impacts speeds were recalculated to minimize errors between the rest positions of the static-crush-based simulations and the original dynamic-crush-based simulations. When Optimizer errors were less than 5% and dynamic crush was within 20% of static crush, 95% of the static-crush-based simulations resulted in bullet vehicle impact speeds within ±3.8 km/h of the dynamic-crush-based simulations.

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