IIHS small overlap frontal crash test ratings and real-world driver death risk

Abstract

Objective

To evaluate how ratings for the Insurance Institute for Highway Safety (IIHS) driver-side small-overlap frontal crash test predict real-world driver death risk in frontal impacts.

Methods

IIHS released the driver-side small-overlap frontal crash test in 2012, after manufacturers had improved vehicle designs to make good ratings in the IIHS moderate overlap frontal crash test virtually ubiquitous. In the small overlap test, the vehicle impacts a rigid barrier at 40 mph (64 km/h) with 25% of the vehicle’s width overlapping the barrier. As in other IIHS tests, vehicles are rated as good, acceptable, marginal, or poor. Drivers’ risk of dying in a frontal crash was estimated by dividing driver deaths by driver involvements in police-reported crashes and modeling with logistic regression to estimate the effect of crash test rating, while controlling for driver age and sex, vehicle type and curb weight, and number of vehicles in the crash.

Results

Drivers of good-rated vehicles were 12% less likely to die in frontal impacts than drivers of poor-rated vehicles. This estimate was 11% for acceptable-rated vehicles and 5% (not statistically significant) for marginal-rated vehicles, compared with vehicles rated poor.

Conclusions

The current study demonstrates that the IIHS driver-side small-overlap crash test rating encourages vehicle designs that reduce drivers’ real-world risk of dying in frontal crashes.

Keywords:

• Crashworthiness
• occupant protection
• frontal impact
• vehicle safety

Disclosure statement

By Traffic Injury Prevention standards, authors are required to disclose all affiliations, funding sources, and other relationships that could be perceived as potential sources of bias. Both authors are employees of IIHS, which thus funded this study that examined an IIHS rating program. The study used publicly-available data sources and established analysis methods to improve understanding of frontal impacts, and its limitations were stated in the discussion section.

Additional information

Funding

This work was supported by the Insurance Institute for Highway Safety.