An Operational Definition of Small Overlap Impact for Published NASS Data 2011-01-0543

The purpose of the study was to identify all small overlap impacts using published coded NASS-CDS data. Three sets of criteria were used: CDC measurements; crush profiles for frontal impacts; and crush profiles for oblique side impacts to the fender component. All criteria were applied to passenger and non-passenger cars and their different vehicle class sizes. Data were analyzed based on fatalities and different levels of MAIS trauma. The overall data set based on CDC codes for 2005 to 2008 NASS-CDS data had 9,206 MAIS=0; 13,522 MAIS=1-2; 3,600 MAIS=3-6; 1,092 MAIS=7; and 961 fatal cases. For the weighted ensemble, these data were: 5,800,295; 4,324,773; 269,042; 219,481; and 44,906 cases, respectively. However, these cases reduced to 1071, 1468, 364, 82, and 87 raw cases with the application of the CDC criteria for frontal impacts. Comparing the CDC criterion to the crush profile for front and side impact criteria, an increase of approximately 44% raw and 40% weighted fatal cases, and 49% raw and 52% weighted MAIS 3-6 cases were found in the ensemble. The operational definition encompassing CDC and crush profiles for front and side impacts provided a more comprehensive assessment of small overlap impacts, hitherto not reported in literature. Using this larger ensemble, it is possible to conduct further analyses of injuries and other crashworthiness-related parameters. In addition, this operational definition can be applied to all databases with CDC codes to classify impacts and crush profiles.