The article «Stand - off detection of
alcohol in car cabins,» by Jarosław Młyńczak, Jan Kubicki, and Krzysztof Kopczyński of the Military University of Technology in Warsaw, details experiments using an external laser device to
detect the presence of
alcohol vapors inside of a moving car.
The device, called a preliminary breath tester, can be pointed toward the driver from outside the car window and
detect the presence of
alcohol vapors as the car window is rolled down.