Consideration of representativeness of real-world accidents and repeatability of new NHTSA oblique offset frontal impact test

The National Highway Traffic Safety Administration has been considering introducing an oblique frontal offset impact test (oblique test) as a new crash test procedure. By means of accident data analysis, it was examined whether this oblique test can represent real-world accidents. Tests were also conducted using two identical vehicles to examine the repeatability of the oblique test. Representativeness of real-world accidents was examined by using the National Automotive Sampling System Crash Worthiness Data System (NASS-CDS) to investigate frontal impact accidents from 2004 to 2008. Repeatability of the oblique test was investigated by conducting the same crash test twice using a midsize sedan. In terms of percentage of the total number of real-world accidents, the most frequent accident modes observed were Full engagement and Offset frontal impacts, accounting for about 30%. Accidents similar to the oblique test accounted for about 10%. In terms of representativeness of severe injuries, the percentage of brain rotational injuries and lower extremity injuries differed from real-world accident statistics. Brain rotational injuries were considerably different from real-world accidents. With regard to repeatability, vehicle deceleration (G) was almost the same. However, the degree of cabin deformation differed because of a difference in the buckling mode of the front longitudinal member. Another notable point in the oblique test is that, as the test vehicle weight increases, the Delta-V decreases. However, this tendency is not observed in real-world accidents. To ensure the validity and significance of introducing this test procedure, more test data are required along with continued evaluation and analysis of occupant protection performance based on actual test results.