Driver injury in near- and far-side impacts: Update on the effect of front passenger belt use

This is a study that updates earlier research on the influence of a front passenger on the risk for severe driver injury in near-side and far-side impacts. It includes the effects of belt use by the driver and passenger, identifies body regions involved in driver injury, and identifies the sources for severe driver head injury.

1997-2015 NASS-CDS data were used to investigate the risk for Maximum Abbreviated Injury Scale (MAIS) 4 + F driver injury in near-side and far-side impacts by front passenger belt use and as a sole occupant in the driver seat. Side impacts were identified with GAD1 = L or R without rollover (rollover ≤ 0). Front-outboard occupants were included without ejection (ejection = 0). Injury severity was defined by MAIS and fatality (F) by TREATMNT = 1 or INJSEV = 4. Weighted data were determined. The risk for MAIS 4 + F was determined using the number of occupants with known injury status MAIS 0 + F. Standard errors were determined.

Overall, belted drivers had greater risks for severe injury in near-side than far-side impacts. As a sole driver, the risk was 0.969 ± 0.212% for near-side and 0.313 ± 0.069% for far-side impacts (P < .005). The driver's risk was 0.933 ± 0.430% with an unbelted passenger and 0.596 ± 0.144% with a belted passenger in near-side impacts. The risk was 2.17 times greater with an unbelted passenger (NS). The driver's risk was 0.782 ± 0.431% with an unbelted passenger and 0.361% ± 0.114% with a belted passenger in far-side impacts. The risk was 1.57 times greater with an unbelted passenger (P < .10). Seat belt use was 66 to 95% effective in preventing MAIS 4 + F injury in the driver. For belted drivers, the head and thorax were the leading body regions for Abbreviated Injury Scale (AIS) 4+ injury. For near-side impacts, the leading sources for AIS 4+ head injury were the left B-pillar, roof, and other vehicle. For far-side impacts, the leading sources were the other occupant, right interior, and roof (8.5%).

Seat belt use by a passenger lowered the risk of severe driver injury in side impacts. The reduction was 54% in near-side impacts and 36% in far-side impacts. Belted drivers experienced mostly head and thoracic AIS 4+ injuries. Head injuries in the belted drivers were from contact with the side interior and the other occupant, even with a belted passenger.