How Ignition Interlock Devices Can Stop Drunk Drivers in Their Tracks

Here's an effective way to stop drunk drivers from taking the road: Make sure that they can't start the car whenever they're under the influence.

Here's an effective way to stop drunk drivers from taking the road: Make sure that they can't start the car whenever they're under the influence.

That's the idea behind alcohol ignition interlock devices, which a growing number of states are using to keep drunk drivers off the road. An ignition interlock device can stop a vehicle from starting if a breathalyzer estimates the person behind the wheel has a blood alcohol content over a preset limit.

"A car is a lethal weapon when operated by a drunk driver," says Steven Benvenisti, a partner in the law firm of Davis, Saperstein & Salomon in New Jersey who also serves on the the board of directors of Mothers Against Drunk Driving (MADD). And Benvenisti would know: When he was in college, a drunk driver slammed into him while he was walking, knocking his body 70 feet away. The crash put Benvenisti in a coma, and doctors told his family he would never recover. Instead, after intensive therapy and now fully recovered, he's devoting his professional career to preventing drunk driving and representing victims.

"States that adopted all-offender ignition interlock device legislation have seen as much as a 43 percent reduction in drunk driving fatalities on their roadways," Benvenisti said.

Ignition interlock setups feature a handheld breath alcohol tester and an electronic control unit connected to the ignition and integrated into the dash, says Derek Latif, media manager for Alcohol Countermeasure Systems (ACS). Before the car can start, the driver has to blow into a disposable mouthpiece on the handset. A sensor within the handset analyzes the breath sample and gives a precise reading of the alcohol level before the car will start.

The system can even prompt drivers to submit to additional tests after they've hit the road to ensure that they haven't had a drink since starting the engine. Interlocks never stop the engine while it is running, but they do keep a record of any violations.

Ignition interlock systems can be ordered by judges after drunk driving convictions. The devices allow people with drunk driving convictions to commute to work, while also reducing the risk of a repeat offense. A growing number of states are turning to ignition interlocks in drunk driving cases: 22 states have laws requiring ignition interlocks for first-time drunk driving convictions while California is running a pilot program for mandatory ignition interlocks in select counties. Just this past week, a law went into effect in West Virginia that lets DUI offenders opt into the state's interlock program more quickly, while a bill requiring ignition locks for first-time offenders is making its way through Ohio's legislature.

It's not just a technology for law enforcement. Benvenisti and Jake Nelson, director of traffic safety advocacy at the American Automobile Association, both say that concerned parents have had ignition interlock devices installed in family cars to prevent teen drivers from starting a car when intoxicated. Devices can also be found in school buses, delivery trucks, and commercial fleets, ACS's Latif said.

The technology behind ignition interlock systems promises to evolve as well. Take last week's meeting of the Automotive Parts Manufacturers Association in Canada where exhibitors showed off a connected car that included an interlock device among its many features. ACS integrated an alcohol interlock handset directly in the computer of the souped-up Lexus, using the QNX operating system instead of a separate electronic control unit. That means the alcohol measurements and driver profiles are seen and set through the infotainment unit. Parents who'd like an ignition interlock in the car to prevent their teenage children from driving drunk could enter a preset level for breathalyzer results and get text messages or emails with the results of any breath test along with a location of the car. Future versions could feature a mobile app that allows an administrator to program interlock settings and see breathalyzer results with GPS coordinates of the car's location in real-time. It's just a concept for now, but it's an interesting indicator of where the technology is headed.

The next phase of keeping drunks from driving is in the works through a program from the Automotive Coalition for Traffic Safety and the National Highway Traffic Safety AdministrationA called Driver Alcohol Detection System for Safety or DADSS. The idea behind DADSS isA to research policy challenges that lead to more widespread use of in-vehicle technology for preventing alcohol-impaired driving--that includes passive forms of monitoring such as sensors that determine alcohol concentration and breath analysis that doesn't require a driver to breathe into a mouthpiece.

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