Stand-off detection of alcohol in moving cars is a particular case of stand-off detection of vapors and gases described in papers.1–3 A device based on this technology can be potentially used to monitor the interior of a vehicle and finally contribute to eradication of the drunken drivers. As a result of such useful application, this technology enjoys popularity with many scientists and scientific institutions, which is shown in many patents.4–7 Much of the effort of the investigators were put into the measurement of the precise value of the alcohol concentration.6,7 Such approach does not seem to be appropriate for the reason that there are many phenomena disturbing precise measurement that cannot be foreseen and eliminated. These are, among others, car cooling system, open windows, window washing liquid (antifreeze), perfumes, or drunken passengers. Moreover, using carbon dioxide (), as in Ref. 7, also appears to be pointless for the very good reason that some passengers may be present in the car, who also exhales . On account of that, the stand-off alcohol detection systems are not able to measure alcohol concentration in driver’s blood, however, with absolute certainty, they are able to indicate the driver suspected of drinking alcohol. Such systems may be extremely useful and highly effective at minimizing the number of cars that should be checked by a policeman using more accurate hand-held equipment.