Alcohol-detection systems could prevent more than a fourth of U.S. road fatalities

July 23, 2020

Alcohol-detection systems that stop people from drinking and driving could prevent more than a quarter of U.S. road fatalities and save upwards of 9,000 lives a year, a new study from the Insurance Institute for Highway Safety shows.

“We haven’t made much progress in the fight against drunk driving since the mid-1990s,” says Charles Farmer, IIHS vice president of research and statistical services and the author of the paper. “This is something that could put a real dent in the alcohol-impaired driving problem.”

Alcohol has been a factor in 30 percent of U.S. roadway deaths every year for the past decade. Meanwhile, police arrest about 1 million people a year for alcohol-impaired driving. Systems that can detect the percentage of alcohol in the driver’s blood and prevent the vehicle from moving if it is higher than a predetermined limit could slash those numbers. Moreover, the technology is already available in the form of an ignition interlock attached to a breath-testing unit. Many jurisdictions require these interlocks for people convicted of alcohol-impaired driving.

In a 2009 survey of U.S. drivers, nearly two-thirds of the respondents said they would support the installation of similar systems in all vehicles, as long as they were fast, accurate and unobtrusive.

Manufacturers such as Volvo have experimented with offering alcohol-detection systems as optional equipment. A public-private partnership called the Driver Alcohol Detection System for Safety (DADSS) project is also road-testing a passive alcohol sensor that detects the driver’s blood-alcohol content (BAC) by measuring the ambient air in the vehicle. How many lives the technology might save would depend on how it was implemented.

To determine the potential impact of different rollouts, Farmer applied the most recent risk calculations for alcohol-impaired driving to U.S. fatal crashes recorded over 2015-18 in which alcohol was detected in the blood of at least one involved driver.

These risk calculations account for the possibility that some of these crashes might have occurred even if all the drivers involved had been sober. The relative risk changes with the age of the driver and BAC level. At a BAC level of 0.09 percent, for instance, a 16-21-year-old driver is 60 times as likely to die in a crash as a sober driver in the same age group. For 22-34-year-olds, that number is 21 times. For drivers 35 and older, it’s 16 times.

Farmer determined that 37,636 crash deaths, or around a quarter of the total number of crash deaths during 2015-18, could have been prevented if the most impaired drivers’ BAC levels had been below 0.08 percent (the legal limit in most states). That works out to an average of 9,409 lives saved every year.

If the same drivers had a BAC of zero, nearly a third of the total deaths, or about 12,000 a year, might have been averted.

If alcohol-detection systems were required for all new vehicles beginning this year, some lives would be saved immediately. However, using data on the age of vehicles in crashes, Farmer found it would be 12 years before the systems became common enough in the U.S. fleet to save 4,596 lives a year — less than half their potential.

If the systems were only required for drivers with an alcohol-impaired driving conviction within the past five years and only blocked them from driving at a BAC above 0.08 percent, they would avert a maximum of 837 crash deaths per year. If they were only required for commercial, government and rental vehicles, the number of lives saved per year would top out around 348.

If systems blocked drivers with any alcohol in their blood from driving, requiring them for those with alcohol-impaired driving convictions would save 986 lives. Requiring them for fleet vehicles would save 465 lives.

The fastest way to reach any of those milestones would be through federal regulation, and bills designed to eventually make alcohol-detection systems mandatory safety features have been introduced in both the House and Senate over the past year. For now, the DADSS project envisions that some manufacturers will begin offering the ambient-air-based system as an option as early as 2025.

Uptake could be slow at first. In the same 2009 survey that demonstrated public support for the concept, less than half of the respondents said they’d be willing to pay extra for an alcohol-detection system, even if it cost less than $500.

But there are ways to encourage manufacturers to make the technology standard.

The DADSS project is a collaboration between the National Highway Traffic Safety Administration and the automaker-funded Automotive Coalition for Traffic Safety, with an expert advisory panel that includes IIHS and other influential safety organizations.

These groups could accelerate adoption of alcohol-detection systems, as they did with side airbags and automated emergency braking. IIHS and similar groups could encourage manufacturers to make alcohol-detection more readily available by requiring such systems for top safety ratings, for example.

“A lot of safety features that start out as options quickly come to be seen as essential,” Farmer says. “It will take time for this technology to reach its full potential, but it is an important part of the overall strategy to reduce impaired driving.”

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