Ignition devices that prevent driving after drinking significantly reduce alcohol-related crash deaths, a new study finds.
Essentially in-car breathalyzers, the “ignition interlocks” led to a 15 percent decline in alcohol-related deaths in 18 states that required them for anyone convicted of drunken driving, the researchers found.
The estimated 915 lives saved from 2007 to 2013 is comparable to the lives saved by mandatory airbag laws and the 21-year-old drinking age, the study authors noted.
“The number of times that I have had to talk to a family and tell them that they lost their son or brother or daughter or sister to something so preventable as a drunk driving crash, it’s hard to count even in my short time of practice — that’s my motivation,” said study author Dr. Elinore Kaufman, a student in the health policy program at the University of Pennsylvania in Philadelphia.
“Other states have proven [a mandatory interlock law] is feasible, and we’re contributing proof that it is effective,” said Kaufman. “There should be no remaining barrier for the remaining half of states to adopt it.”
J.T. Griffin, chief government affairs officer for Mothers Against Drunk Driving (MADD), welcomed the findings. He said the study validates what MADD has been saying since 2006.
“We’ve been working to pass these laws, and we think you can get better than a 15 percent reduction” in alcohol-related crash deaths, he said. “But a 15 percent reduction is really good. If we could do it nationwide, it could save 1,500 lives a year. That’s a lot of people.”
Thirty percent of deadly car crashes in the United States are alcohol-related, claiming an estimated 11,000 lives every year, the study authors said.
To start a car equipped with an ignition interlock, you blow into the breathalyzer. If your blood alcohol count is over a set limit — usually 0.02 — the engine won’t start. Someone with a blood alcohol level of 0.02 is considered mildly impaired. Many people reach that level after just one drink.
The devices have previously been shown to curb repeat DWI offenses by between 50 percent and 90 percent, the researchers said. The new study is believed to be the first to examine whether ignition locks also reduce alcohol-related injuries and deaths.
It was published online March 17 in the American Journal of Public Health.
Twenty-five states now have mandatory interlock laws, and Pennsylvania and Maryland are poised to follow suit. Some other states require the technology only for repeat offenders or those with very high blood alcohol counts, while others leave the decision up to a judge, the researchers said.
The U.S. Centers for Disease Control and Prevention recommends all states require alcohol ignition locks for DWI offenders. It is illegal nationwide to drive with a blood alcohol content (BAC) of 0.08 or higher.
The study was based on an analysis of U.S. National Highway Traffic Safety Administration death rates from 1999 to 2013. It compared crash deaths in 18 states that required everyone convicted of drunken driving to use the devices to 32 states that did not.
Most states with mandatory interlock laws saw significant declines in alcohol-related crash deaths in their law’s third year, according to the study.
Mandatory-interlock states had 4.7 alcohol-related crash deaths a year for every 100,000 people, on average, compared to 5.5 per 100,000 in states without the law, researchers said.
Public support for the devices — even among those who admit to driving under the influence — is strong, the researchers noted.
Griffin said convicted DWI offenders often continue to drive even if their license is suspended or revoked. Ignition locks are effective and practical, he added.
“With the interlock on board, they can’t drive drunk. It’s a win for the offender: They keep their license and can do the basic things they need to do,” Griffin said. “For us, as law-abiding citizens, they can’t drive drunk and hit us while out on the roads.”
Griffin said the challenge now is overcoming continued resistance from “angry factions” of the alcohol and hospitality industries and some judges who prefer more leeway to sentence offenders.
The U.S. National Institutes of Health has more about how alcohol affects drivers.