The appropriateness of the set of eight frontal stiffness coefficients used by the CRASH3 (Calspan Reconstruction of Accident Speeds on the Highway) program to estimate vehicle deformation energy, and to subsequently derive estimates of vehicle delta-V, is examined. This examination consists of constructing so-called CRASH energy plots based on 402 frontal fixed barrier impact tests contained in the National Highway Traffic Safety Administration (NHTSA) Vehicle Test Center Data Base (VTCDB) digital tape file. It is concluded that the use of category coefficients within the CRASH3 program can result in large delta-V errors, reaffirming the inappropriateness of this program for use in individual accident reconstructions. The use of the CRASH3 category stiffness coefficients is seen: (1) to generally overestimate vehicle energy absorption for vehicles with small amounts of frontal crush; and (2) to underestimate vehicle energy absorption for vehicles sustaining large crush. Comparisons among the stiffnesses of different size vehicles indicates little or no dependence of stiffness on vehicle size. It appears that the current set of eight frontal stiffness coefficients could, for statistical purposes, be reduced to two: a set applicable to passenger cars, and a second set for light trucks and vans. (A)
Abstract