This paper studies the validity of linear ΔV-crush relationship for modern passenger cars and describes the experimental work done to investigate the crush-energy vs. residual crush behavior for a number of vehicle models. It also discusses the repeated test technique (suggested by C. Warner et al.) in which the same vehicle is impacted repeatedly at lower speeds to yield multiple data-points for impact behavior at higher speeds. The technique is based on the assumption that the vehicle deforms under repeated impacts in a manner similar to that at a higher speed having the same impact energy. The validity of this technique and the results from staged crash tests for front and rear impacts are discussed. The work reported in this paper was executed under contract to the National Highway Traffic Safety Administration (NHTSA) as a part of their research.