The report focuses on the most important predictors of occupant injury in a collision: crash type and crash severity, automobile size, safety belt use, and occupant age and gender. Objective, Scope, and Methodology

			Objective

The objective of this report is to examine the independent effects of a number of factors—crash type, crash severity, automobile weight and size, safety belt use, and occupant age and gender—on the risk of injury in an automobile crash. First, some types of crashes are more severe than others. Most importantly, although increasing weight and wheelbase reduces the risk of driver injury in one-car nonrollover crashes and in collisions with other cars or light trucks, drivers in heavier cars were much more likely to be hospitalized or killed in one-car rollover crashes than were drivers of lighter automobiles. Multivehicle collisions are a greater source of injury for women than they are for men. Men drivers are involved in one-car crashes more often than women drivers. Factors Affecting Older Drivers

Crash Type. And safety belts are extraordinarily effective; alone, they are much more effective at reducing serious injuries than are air bags alone. As we demonstrated in chapter 2, compared to women and older drivers, not only are men drivers and younger drivers involved in more automobile crashes but also the crashes they are particularly likely to be involved in have comparatively severe consequences—that is, single-car crashes have much higher driver injury rates than multivehicle crashes. Compared to men and younger drivers, women and older drivers are involved in fewer automobile crashes, and the crashes they are involved in are, on the average, less severe, since they are less likely to be involved in single-car crashes than in multivehicle collisions. Current safety regulations and automobile safety designs emphasize protection in high-speed frontal collisions, and men drivers and younger drivers are more likely to be in single-car crashes, which disproportionately involve frontal impacts. Similarly, safety belts are more effective in frontal than in side impacts (for example, Evans, 1990), and because of this, safety belts have a somewhat greater benefit in single-car crashes than in collisions with cars and light trucks.
Why GAO Did This Study

Pursuant to a congressional request, GAO reviewed highway safety, focusing on: (1) the most important predictors of injury in an automobile crash; (2) how the risk of injury in a crash is affected by the severity and type of crash, automobile size, safety belts and airbags, and the occupants' age and gender; and (3) areas for further reducing automobile occupants' crash injury risks.

What GAO Found

GAO found that: (1) the most important determinants of driver injury in car crashes are speed at impact, the type of crash, safety belt use, driver age and gender, and automobile weight and size; (2) injury is more likely in high-speed crashes, one car crashes, frontal crashes, and rollovers; (3) occupants of heavier and larger cars are less likely to be injured, but those cars pose a greater danger to persons in multivehicle crashes; (4) heavier cars offer more protection in one-car nonrollover and multivehicle crashes, but occupants of these cars are subject to more injury in rollovers than are occupants of lighter cars; (5) although safety belts reduce injury risks overall, they are most effective in rollovers, single car crashes, and frontal crashes; (6) air bags are only effective in frontal crashes and are less effective than safety belts alone; (7) although they are involved in fewer crashes overall, female and older drivers are more often injured than male and younger drivers are in similar crashes; (8) safety belts are not as effective for women as they are for men; (9) female and older drivers are involved in more multivehicle crashes and male and younger drivers are involved in more single car crashes; (10) older drivers tend to be involved in more side impact crashes; and (11) the government and manufacturers are working to improve automobile safety for each category of driver.