Interventions to reduce risks associated with vehicle incompatibility: Results of a systematic review

Introduction: Vehicle incompatibility refers to “design differences between vehicle types which result in disproportionate damage patterns to the vehicles involved in a collision.” Occupants of smaller, lighter passenger cars are more likely to be killed or injured in collisions with larger, heavier sport-utility vehicles (SUVs) and light trucks than with other cars. Proven interventions are needed to reduce incompatibility or its consequences. Methods: We conducted a systematic literature review to identify evaluations of interventions to reduce incompatibility. We reviewed engineering, biomedical, and other technical literature. To be included, a study must: 1) evaluate an intervention to reduce vehicle incompatibility, or its consequences, in a crash 2) report new research; and 3) be published in English from 1990 to 2010. Excluded were studies evaluating interventions solely designed to prevent crashes from occurring. Results: Seventeen studies met our inclusion criteria. Study methods included epidemiologic analyses of real-world crashes, crash testing, or computer simulations. Interventions were designed to reduce the aggressivity of larger vehicles or improve the crashworthiness of smaller vehicles. Effective interventions included: 1) modifying bumper heights; 2) improving side strength of smaller vehicles; 3) side-impact airbags; 4) changes to vehicle stiffness; and 5) modifications of other front end structures. Conclusions: Some of interventions shown to be effective are now in wide use (e.g. side impact airbags). But others have yet to be required by regulators or widely implemented by manufacturers. If larger, heavier vehicles remain on the nation's road, manufacturers have an obligation to reduce risks for occupants of other vehicles.