http://www.russia-ic.com/news/show/8212/
Engineers from St. Petersburg developed “Alco-laser” (a unique sensor, which detects alcohol vapours inside a moving car) and displayed it at largest industrial fair in European Hannover Messe – 2009.
The device contains a special laser, which is safe for eyes. The sensor is able to detect alcohol vapours inside a moving car through a windscreen, which is not made of solar tinted glass. Laser’s sensitivity is about 1 part of alcohol per million of other particles, which is equal to 1 liter (or quart) of beer or 100 grams of vodka.
The sensor is installed as high as several meters above the road and, when alcohol vapours are detected, passes information about the car of a possible drunken driver to the nearest road police station. Police officers will then determine, whether a driver of a passenger drank alcohol.