The concept of compatibility includes not only the safety of the occupants within the subject vehicle itself, but also the safety of occupants in other vehicles that are involved in the collision. The term self-protection describes the safety afforded to the occupants within a vehicle, while partner-protection describes the safety afforded to the occupants of the crash partner vehicle. Early research identified vehicle weight as having a critical but not exclusive role in defining crash outcomes. The geometry and vehicle stiffness or crush characteristics were also observed to play a significant role.

This study uses the New Car Assessment Program1 (NCAP) frontal barrier test data to find a suitable metric to assess the effect of incompatibility in crashes involving light passenger vehicles. The number of drivers with AIS 3+ injuries in head on crashes between passenger car (PC) and light truck vehicle (LTV) is used to compute the effectiveness of the metric.

NCAP crash test data for 239 vehicles were used in calculating the value of “distance from ground to the center of velocity change”. Ten years of National Automotive Sampling System /crashworthiness data systems2 (NASS/CDS) data were used to demonstrate the metric. The crash compatibility metric developed can be used to compare the number of injuries that result in PCs - LTVs head on crashes.

Most safety benefits can be achieved by changes in the metric, specifically, adjusting for vehicle size (height) and the structural characteristics (stiffness). Hence the metric can be used as a measure of compatibility in crashes between vehicles.

This study is limited to investigation of incompatibility in full head-on crashes. This paper develops a new comprehensive metric that can quantify the compatibility disparity.