CRASH (Calspan Reconstruction of Accident Speeds on the Highway) is one of the primary tools used by the National Highway Traffic Safety Administration (NHTSA), U.S. Dept. of Transportation, for estimating the severity of impacts. It is a computer program which is used to estimate the velocity change (ΔV) of the centers of gravity of vehicles in an accident. This paper studies the validity of the linear ΔV vs. crush relationship used in CRASH3 for modern passenger cars. It describes the experimental work done to investigate the crush-energy vs. static crush for a number of models in side impacts. Finally, the crush-energy vs. residual crush behavior for a large number of vehicle models tested for NHTSA has been characterized and tabulated.