Fatalities by Seating Position and Principal Direction of Force (PDOF) for 1st, 2nd and 3rd Row Occupants 2008-01-1850

Purpose: A better understanding of rear occupant fatality risks is needed to guide the development of safety improvements for 2^nd and 3^rd row occupants. This study investigates fatal accidents of 1^st, 2^nd and 3^rd 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 (1^st, 2^nd and 3^rd 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 2^nd row occupants in FARS. About 2,080 deaths occur to 2^nd row occupants annually. 38.4% died in rollovers and 26.8% in frontal crashes. There were about 300,000 2^nd 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 3^rd row occupants in FARS. About 94 deaths occur to 3^rd row occupants annually. 61.0% died in rollovers, and 18.6% in frontal crashes. There were about 17,900 3^rd 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: 2^nd and 3^rd 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 2^nd row right and 7-9 o'clock for 2^nd row left occupants).