Comparison of Occupant Fatality Factors in Underride Passenger Car Accidents in India and USA

Underride accidents constitute around 5% and 4% of all accidents in India and the US respectively. Yet, the passenger car occupant fatality risk is the highest in this accident configuration when compared to other configurations. Especially in India, the fatality rate is even higher due to minimal usage of underride protection devices in the front, rear and sides of commercial vehicles. This study specifically aims to compare the factors influencing occupant fatality in the rear underride accident configuration, in India and the US. The influencing factors are identified by performing Principal Component Analysis (PCA), which is a linear feature extraction technique. The accident databases considered for this study are RASSI and NASS-CDS. After querying, a total of 88 cases from RASSI and 202 cases from NASS-CDS were extracted, where a passenger vehicle was involved in a rear underride accident with a commercial vehicle. The relevant variables involved in the rear underride accident configuration were initially identified for analysis, followed by an observation of their trends. The data corresponding to these variables were analyzed using PCA. The variables which had the highest influences were identified by their corresponding loading scores. The results were discussed to understand and compare the variables that influence rear underride accidents in India and the US. The limitation of the study is that the accident data collected in RASSI database is not yet representative of national accident data, and that NASS-CDS data has minimal information regarding commercial vehicle involved in the accident. Keywords: Underride accidents, feature extraction, Principal Component Analysis, loading score