ANN ARBOR, Michigan — According to a new study from the University of Michigan, 85 percent of alcohol-related traffic deaths in the U.S. could be prevented if all new cars were equipped with breath-testing ignition interlocks.
In addition, 84-89 percent of nonfatal injuries from vehicle crashes could be avoided with these devices, the study found.
The study was published in the American Journal of Public Health.
An ignition interlock is similar to a breathalyzer. When installed in a vehicle it prevents the engine from starting if a driver's breath indicates a blood-alcohol level that is beyond a pre-determined level.
The study's results are based on two data sets commonly used to analyze crashes: those from the Fatality Analysis Reporting System and the National Automotive Sampling System's General Estimates System. Both are maintained by the National Highway Traffic Safety Administration.
The researchers, from the U-M Injury Center and U-M Transportation Research Institute, created models that projected the impact of installing these ignition interlock devices in all newly purchased vehicles over a 15-year period.
Their modeling concluded that during that span of time more than 59,000 deaths and 1.25 million nonfatal injuries could be prevented if all new vehicles included the devices as standard equipment.
In addition, they estimated that over 15 years the interlocks would save U.S. society $343 billion, and the cost of installing them would be recouped in just three years.
"We knew our modeling would yield significant results, but the sheer numbers of preventable fatalities and serious injuries were surprising," said the study's lead author, Dr. Patrick Carter, assistant professor at U-M Medical School and core faculty at the U-M Injury Center, in a statement. "Our analysis clearly demonstrates the significant public health benefit and societal cost savings associated with including alcohol ignition interlock devices as standard equipment in all new cars."
Ignition interlocks are currently most often installed by court order on vehicles owned by drunk-driving offenders. Although laws vary, all U.S. states allow or mandate judges to order their use in the case of repeat offenders, when alcohol levels are unusually high or under other specific circumstances.
NHTSA figures indicate that interlocks are used in approximately 100,000 drunk-driving cases per year but are only mandated to be installed in about 20 percent of the cases in which they could be used. As a result, some organizations, such as MADD (Mothers Against Drunk Driving) advocate requiring them for all drunk drivers, even first-time offenders, with no exceptions.
In Sweden, according to GreenFleet Europe, commercial vehicles contracted for public works must have ignition interlocks, and France requires them for buses that transport children. To date, however, no jurisdiction in the U.S. or anywhere else appears to require interlocks for all vehicles.
Edmunds says: This study's findings are dramatic, and while mandating interlocks for drunk drivers seems conceivable, it's hard to imagine them being installed in all new cars.