People driving while intoxicated still cause about 13,000 deaths a year in the United States. And of the 1.4 million arrests made, one-third involve repeat offenders. The greatest potential of ignition interlocks is to reduce this recidivism.
These hand-held devices, typically attached to dashboards and connected to the ignition, use fuel-cell technology to measure the concentration of alcohol in a person’s breath. Although they are made by various companies, all ignition interlocks conform to strict standards of accuracy set by the National Highway Traffic Safety Administration. If too much alcohol is detected, the car will not start.
A person who has been drinking might naturally think of fooling the device by persuading a sober person to start the engine, but that is not enough to subvert the system, because the device requires breath samples while the person drives — at random intervals of five minutes to an hour. (At least one company is also integrating cameras with the interlocks to photograph the driver when he provides a breath sample.) The unit keeps a log of all tests, and it is sealed so that any attempts at tampering can be detected.
Ignition-interlock devices are not perfectly effective; a drunk can often borrow another car. But in one recent study they were found to reduce repeat drunk-driving offenses by 65 percent. If they were widely installed, the devices would save up to 750 lives a year, a recent National Highway Transportation Safety Administration report estimated.
A NYT contributor makes the case for ignition-interlock breathalyzers for drunk drivers.