Ignition interlock devices are used in some states to prevent those with prior DUI convictions from driving drunk again. The devices require a driver to blow into them before the vehicle can be started. Some safety experts have wondered if similar devices should be required for all vehicles, regardless of the conduct of a particular driver. Apparently, the National Highway Traffic Safety Administration is also considering the value of technology in deterring drunk driving.
NHTSA's associate administrator of vehicle safety, Nat Beuse, indicated that the agency has worked with two suppliers on creating a device like an ignition interlock, but one that would work passively. Drivers would not be required to blow into the device, necessarily. The idea is to develop a system that gathers data without the driver taking any direct action. If the device determined that the driver was intoxicated, it would presumably require the driver to stop and blow into a breathalyzer to prove they were not impaired.
The level of intrusion into the driver's life may be a significant factor in whether such technology ever gains acceptance. Ignition interlock devices spark little controversy because those who use them have already been convicted of driving drunk. Drivers with no criminal background may be less enthusiastic about paying for a device to monitor their physical condition. Safety technology such as seat belts and air bags can benefit drivers who do nothing wrong. The proposed device would only benefit a lawful driver indirectly, by stopping others with similar devices from driving impaired.
Drunk driving is still a large contributor to traffic fatalities in the United States. Approximately one-third of motor vehicle fatalities involve a drunk driver. That equates to more than 10,000 deaths per year caused by drivers who have had too much to drink. Combating drunk driving is one of the easiest ways to reduce auto fatalities.
Source: The Car Connection, "Why Can't Cars Tell When A Driver Is Drunk? NHTSA's Working On That" by Richard Read, 5 August 2014