Initial Assessment of the Next-Generation USA Frontal NCAP: Fidelity of Various Risk Curves for Estimating Field Injury Rates of Belted Drivers

Various frontal impact risk curves were assessed for the next-generation USA New Car Assessment Program (NCAP). Specifically, the “NCAP risk curves” — those chosen by the government for the 2011 model year NCAP — as well as other published risk curves were used to estimate theoretically the injury rates of belted drivers in real-world frontal crashes. Two perspectives were considered: (1) a “point” estimate of NCAP-type events from NCAP fleet tests, and (2) an “aggregate” estimate of 0 ≤ ΔV ≤ 56 km/h crashes from a modeled theoretical vehicle whose NCAP performance approximated the average of the studied fleet. Four body regions were considered: head, neck, chest, and knee-thigh-hip complex (KTH). The curve-based injury rates for each body region were compared with those of real-world frontal crashes involving properly-belted adult drivers in airbag-equipped light passenger vehicles.

The assessment yielded mixed results. For the head, all of the studied curves yielded injury rates within the confidence limits for both the point and aggregate estimates. For the neck, the NCAP risk curve for the combined-loading metric (N_ij) yielded results well outside the confidence limits for both the point and aggregate estimates. For the chest, the NCAP risk curve yielded results within the confidence limits for the point estimate, but the result was somewhat lower than the mean. For the KTH, all of the studied curves yielded results outside the confidence limits for both the point and aggregate estimates. Accordingly, different available risk curves were recommended for the neck and chest, and the need for research to improve the KTH risk estimates was demonstrated.