Interventions to reduce risks associated with vehicle incompatibility.

Occupants of smaller, lighter passenger cars are more likely to be killed or injured in collisions with larger, heavier sport utility vehicles and light trucks than in collisions with other cars. Interventions are needed to reduce this vehicle "incompatibility" and its consequences. The authors conducted a systematic literature review to identify evaluations of interventions to reduce incompatibility. They reviewed engineering, biomedical, and other technical literature. To be included, a study must have 1) evaluated an intervention to reduce vehicle incompatibility, or its consequences, in a crash; 2) reported new research; and 3) been published in English from 1990 to 2010. Seventeen studies met the inclusion criteria. Interventions were designed to reduce the aggressivity of larger vehicles or improve the crashworthiness of smaller vehicles. Effective interventions included 1) modified bumper heights, 2) improved side strength of smaller vehicles, 3) side-impact air bags, 4) changes to vehicle stiffness, and 5) modifications of other front-end structures. Some of the interventions shown to be effective are now in wide use. However, others have yet to be required by regulators or voluntarily agreed to by manufacturers. If larger, heavier vehicles remain on the nation's roads, countermeasures will be needed to reduce risks for occupants of other vehicles.