Probability of Frontal Airbag Deployment in Bumper-Bumper and Underride Collisions 2019-01-0620

Airbag deployment thresholds can be a useful metric of collision severity in accident reconstruction applications. The National Automotive Sampling System (NASS) has provided a publicly-available database of real-world motor vehicle collisions, including more than 10,000 event data recorder (EDR) reports retrieved from airbag control modules. These reports typically indicate the airbag deployment status and the corresponding Delta-V of each recorded event. A prior study analyzing crash data in the NASS database demonstrated the airbag deployment threshold varies between vehicle manufacturers and over time. However, the analysis was limited to Ford and GM vehicles due to insufficient data. This paper expands on the prior study of frontal airbag deployment thresholds by analyzing newer years of NASS EDR data (4,000 additional reports). We found that the Delta-V threshold for a 50% probability of deployment event is higher for Toyota than for GM and Ford vehicles. Moreover, SUVs and pickup trucks had higher deployment thresholds than sedans. An increase in Delta-V thresholds was observed for more recent vehicle model years. A higher Delta-V is required for frontal airbag deployment in underride collisions, in which a sedan contacted a vehicle with higher ground clearance (SUV, pickup truck, or van), compared to collisions with direct bumper-bumper engagement. Based on the findings, we developed a logistic regression model that predicts the probability of frontal airbag deployment with a known change in velocity (ΔV = 0 to 45 mph), vehicle manufacturer (GM, Toyota, Ford), vehicle type (sedan, SUV, pickup truck), model year (1994-2001, 2002-2016), and impact configuration (underride, bumper-bumper) with 82% accuracy. This study provides information about airbag deployment behavior beyond what is reported in owner’s manuals and National Highway Traffic Safety Administration (NHTSA) guidelines.