Injury probability and risk in frontal crashes: effects of sorting techniques on priorities for offset testing

Front occupant exposure, MAIS2+ and MAIS3+ injury risk, and maximum-injured body regions were studied in frontal offset impacts. The effect of overlap amount was evaluated in three data subsets from 9,902 accident-involved Volvo cars with at least SEK35,000 (= US$5,000) damage. The subsets were selected by a MAIS2+ or MAIS3+ injured co-occupant or by an equivalent barrier speed (EBS) > 20 mph, and consisted of 661 or 249 cases and 654 cases, respectively. Age and gender effects were minimized. Collisions with 1/3 to 2/3 overlap were most frequent, but the most injurious crash type was influenced by the data sorting technique. The EBS criterion seemed to select crashes of more comparable severity and this dataset may be most appropriate to evaluate overlap effects. With EBS > 20 mph, the highest injury risk occurred in 1/3 overlap crashes, at 62% for MAIS2+ and 44% for MAIS3+ injury. This was two to three times higher than the corresponding risk in full frontal crashes. Head and chest were the most severely injured body regions, but lower-extremity injuries became more important as overlap decreased.