The association between data collected in IIHS side crash tests and real-world driver death risk

Abstract

Objective The Insurance Institute for Highway Safety (IIHS) side crash test has led to crashworthiness improvements, and both overall and component ratings have been shown to be associated with real-world death risk. The objective of the current study was to investigate how crash test measurements, on which component ratings are based, are associated with real-world death risk. Methods Driver deaths and police-reported crash involvements were extracted from national crash databases for left-impact crashes of passenger vehicles with standard-feature, head-protecting side airbags for calendar years 2000–2016. Risk of driver death in left-impact crashes was estimated as the number of driver deaths divided by the number of driver police-reported crash involvements. Logistic regression was used to estimate the association between crash test measurements and death risk, controlling for driver and vehicle information. Results All crash test measurements investigated were associated with driver death risk. For instance, a 10 cm reduction in B-pillar intrusion, a measure of post-crash occupant survival space, was associated with 30% lower driver death risk. For most measures, at least 75% of study vehicles were within the good rating boundary for that measure, and still these measures were associated with driver death risk. Fewer than half of study vehicles earned a good rating for B-pillar intrusion. Conclusion Because performance in measures collected in the IIHS side crash test are strongly associated with real-world driver death risk, one of the ways the crash test program could continue to encourage crashworthiness improvements is by requiring stronger performance on these measures.