Vehicle design parameters that affect partner protection in front-to-front and front-to-side crashes

Abstract
Improving passenger vehicle compatibility in a changing fleet requires identifying design parameters that contribute to partner protection and quantifying their relative importance. Many studies have identified one or more factors relevant to compatibility, but the few that have compared these factors’ contribution to real-world crash outcomes have been restricted to specific vehicle types. This study was designed to provide effect estimates that can be compared to each other and applied across vehicle types and that are relevant to vehicles with modern levels of crashworthiness. Front-to-front and front-to-left crashes in which the lighter vehicle was the side-struck vehicle were analysed. Partner protection metrics (PPMs) were calculated for 497 vehicle designs using data from the US New Car Assessment Program full-width rigid barrier and/or IIHS offset deformable barrier test. These were matched to approximately 75,000 and 106,000 police-reported front-to-left and front-to-front crashes, respectively, and 3,200 fatal front-to-front crashes from 2000 to 2023. Logistic regression analyses identified that mass was the dominant vehicle design parameter affecting injury outcomes in all three crash datasets. Beyond mass, multiple stiffness-related PPMs had statistically significant effects on partner driver injury in both crash modes, while centre-of-gravity height was another predictive factor in front-to-front crashes.