Nissan is testing alcohol-detection sensors that check odor, sweat and driver awareness, issue a voice alert from the navigation system and lock up the ignition if necessary.
Odor sensors on the driver and passenger seats read alcohol levels, while a detector in the gear-shift knob measures the perspiration of the driver's palm when starting the car.
Other carmakers with detection systems include Sweden's Volvo, which has developed technology in whichunit in the seat belt before an engine can start.
But Nissan's car also includes a mounted camera that monitors alertness by eye scan, ringing bells and issuing a voice message that a driver should pull over and rest.
The car technology is still in development, but Nissan general manager Kazuhiro Doi said the combination of detection systems will ultimately keep an eye on who's behind the wheel.
"We've placed odor detectors and a sweat sensor on the gear shift. But for example if the gear-shift sensor was bypassed by a passenger using it instead of the driver, the facial recognition system would be used," Doi said.
Also keeping a short leash on drivers, car seat belts tighten if drowsiness is detected, while an on-road monitor checks whether a car is staying properly inside its lane.
Japan's No. 3 carmaker has no specific timetable for marketing, but aims to yoke a number of technologies to cut the number of fatalities involving its vehicles to half the 1995 levels by 2015.
Doi said that testers still have to distill exactly what impairment means: "If you drink one beer, it's going to register, so we need to study what's the appropriate level for the system to activate."