Viano, D. and Parenteau, C., "Fatalities by Seating Position and Principal Direction of Force (PDOF) for 1st, 2nd and 3rd Row Occupants," SAE Technical Paper 2008-01-1850, 2008, doi:10.4271/2008-01-1850.
Purpose: A better understanding of rear occupant fatality risks is needed to guide the development of safety improvements for 2nd and 3rd row occupants. This study investigates fatal accidents of 1st, 2nd and 3rd row occupants by principal direction of force (PDOF), irrespective of restraint use. It determined the number of fatalities, exposure and fatality risk.Methods: 1996-2005 FARS was analyzed for occupant fatalities by seating position (1st, 2nd and 3rd row) and principal direction of force (1-12 o'clock PDOF, rollover and other/unknown). Light vehicles were included with model year 1990+. 1996-2005 NASS-CDS was similarly analyzed for occupant exposure. Fatality risk was defined as the number of fatalities in FARS for a given category divided by the exposure from NASS-CDS.Results: Ten percent (9.6%) of fatalities were to 2nd row occupants in FARS. About 2,080 deaths occur to 2nd row occupants annually. 38.4% died in rollovers and 26.8% in frontal crashes. There were about 300,000 2nd row occupants annually in towaway crashes in NASS-CDS, representing 12.3% of all occupants. Most are exposed to front impacts (51.5%) followed by side impacts (21.0%). Rear impacts are the lowest frequency (10.0%). Fatality risk is highest in rollovers (2.52%) followed by right-side impacts (0.91%). Less than one percent (0.4%) of fatalities was to 3rd row occupants in FARS. About 94 deaths occur to 3rd row occupants annually. 61.0% died in rollovers, and 18.6% in frontal crashes. There were about 17,900 3rd row occupants annually in tow away crashes in NASS-CDS, representing 0.7% of all occupants. Fatality risk is highest in rollovers (2.01%) followed by left-side impacts (0.37%).Conclusions: 2nd and 3rd row occupants have lower overall risks than the driver. However, they have high risks in crashes where the PDOF is in the proximity of their seating position. This involves oblique side impacts and oblique rear impacts (3-5 o'clock for 2nd row right and 7-9 o'clock for 2nd row left occupants).