Factors influencing the patterns of injuries and outcomes in car versus car crashes compared to sport utility, van, or pick-up truck versus car crashes: Crash Injury Research Engineering Network Study.

BACKGROUND

Data using crash dummies suggest that motor vehicle crashes (MVCs) involving passenger sedans (S) vs sport utility, vans, or light trucks (SUVTs) produce more severe injuries than those involving two sedans (SvS). However, no detailed data regarding pattern of injuries or force mechanisms involved have been presented in real patients.

METHODS

The relationship of injury patterns and severities with MVC reconstruction data were obtained in 412 MVC patients, drivers or front seat passengers. Crashes were examined with regard to impact direction, frontal (F) or lateral (L) crashes, vehicle mass ratio, ISS, DELTA V, seat belt use, and airbag deployment (AB).

RESULTS

In 309 F-MVC, AB reduced overall ISS (24.3 to 17.9) with a reduction in the mean severity of traumatic brain injury (TBI) GCS < or = 12, from 48% to only 28%. This AB protection from TBI was preserved as DELTA V increased to > 30 mph even though non-AB protected body areas (thorax, lung, liver, and lower extremity injuries) all increased. When vehicles of incompatible size and mass (SUVT) had F-MVC with sedans the incidence of severe TBI rose as did face lacerations despite AB or belt use. In L-MVC between SUVT and sedans compared with SvS MVC, there was a cephalad shift in body injuries with increased thorax, but decreased lower extremity injuries. The incidence of TBI increased. Analysis of injury contact sites (hits) showed more hits and a wider distribution of contract sites in SUVT vs sedan MVC. These appeared due to the greater mass excess and larger mass ratio, hood height, and width in the F-SUVT vs S crashes. All of these factors plus the increased bumper height above the body frame side-door sill were injury causal factors in the L-SUVT vs S MVCs.

CONCLUSION

Both F and L crashes between sedans and SUVT with a high mass ratio shift the pattern of injury cephalad with increased thorax and intrathoracic organ injuries, and more severe TBI. These data suggest that improved head and thorax side-impact buffering and design features which transmit MVC forces from the higher front end of the larger mass SUVT to the frame of the sedan may better protect sedan occupants from side-impacts.