Science

Lasers could be used to detect drunk drivers

Scientists have used lasers to gauge the alcohol vapor content of the air in moving cars (Photo: Shutterstock)
Scientists have used lasers to gauge the alcohol vapor content of the air in moving cars (Photo: Shutterstock)
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Scientists have used lasers to gauge the alcohol vapor content of the air in moving cars (Photo: Shutterstock)
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Scientists have used lasers to gauge the alcohol vapor content of the air in moving cars (Photo: Shutterstock)

It used to be that the only way you could get a speeding ticket was if a police officer personally witnessed your overly-fast driving. Then photo radar came along. Well, when it comes to drunk driving, lasers could soon be the equivalent of photo radar. Polish researchers at the Military University of Technology in Warsaw have demonstrated how the high-intensity beams of light can be used to detect the presence of alcohol – even exhaled alcohol – in passing vehicles.

The scientists used a type of stand-off detection, the general term for the ability to identify substances at a distance. Typically, it's used to detect things such as explosives or other hazardous materials, without getting dangerously close to them.

In this particular case, a laser was shone through a car's cabin via its windows, onto a mirror located on the other side of the car, and then reflected back through the windows to a photodetector. Inside the car, alcohol vapor was emitted into the air, in a concentration similar to what would be exhaled by someone with a blood alcohol level of 0.1 percent.

By analyzing the reflected laser light, it was possible to determine how much of the original beam had been absorbed by alcohol vapor in the vehicle's cabin. This in turn allowed the scientists to accurately deduce the amount of alcohol in the air.

The idea is that from there, an automated system could snap a photo of the car showing its license plate number, which would then be transmitted to police waiting down the road. Officers could then pull the car over and subject the driver to a breathalyzer test. The system could not simply issue a ticket based on the laser reading, as the alcohol vapor could be coming only from passengers in the car, or from spilled alcohol.

It's definitely possible that drunk drivers could thwart the system by keeping their windows rolled down to air out the cabin, or by placing laser-blocking items on the window glass. In those cases, however, the system could still alert officers to the fact that those vehicles might be ones to check out.

The scientists are now in the process of optimizing the technology for commercialization by making it more compact, robust and user-friendly.

A paper on their research was recently published in the Journal of Applied Remote Sensing.

Source: International Society for Optics and Photonics

14 comments
Anne Ominous
In my area, police cannot stop drivers for ANY reason other than probable cause that a crime (or at least traffic infraction) has been committed by someone. And in the case of alcohol, the driver must be that someone. Alcohol vapor that MIGHT HAVE been coming from ONE OF the people in the car does not even come close to probable cause. A police department that tried this would be in serious trouble, very quickly.
Daniel Bruce
Seems like a Big Brother kind of thing.
Skipjack
Better not use an alcohol based window cleaner then... This is idiotic!
VirtualGathis
I agree with Anne. As described in the article as a photo ticket machine this is worthless in the USA. There are too many ways that alchohol vapor could be in a vehicle other than the driver exhaling it. Spilled drinks drunk passengers... Heck every taxi driver in existence would get tickets from this machine between drunk passengers, spilled or vomited alchohol, etc they would always get a positive from this machine.
lwesson
We have gone from Sheriff Andy to Deputy Barney Fife armed with machine guns and armored cars, while dressed up as some kind of RobCop warriors, all with bullets, lots of bullets this time. If you think that commercial interests are not drooling over this Orwellian 1984 Sci Fi device, Andy will just nod that they are. Errors? Who cares about errors these days as it seems that it is certainly not the police. Perhaps after much legal battling, this will be SWAT-ted down as intrusive, ineffective, a violation of Civil Rights etc and most importantly, since $$$ is the single most important driver for anything so it seems, the cost will be much greater than expected. Ooops! "Put away your laser Barney Fife."
Martin Winlow
I'm sorry, but at least two of the authors of these rather silly responses to this article haven't even bothered to read it properly as it makes it very clear (if it were not blindingly obvious) that fines for drink driving could not be issued simply on the basis of this technique. Personally, I'd far rather have this set up than be stopped for another reason and have to waste time giving a breath test when I haven't been drinking. But then I would as I had the same idea 30 years ago after reading about a spectrum analyser been used to police the emissions of a factory chimney, remotely. As for 'probable cause' twaddle, what would rather have? Perhaps you'd be happy for the police to have to wait until the car is wrapped around a lamp post or sitting on top of a innocent pedestrian before they have the 'right' to breath-test the driver? MW
Koala
its not a ticket machine, it is used as an alerting device... a cop would actually have to do the pull over and inspection/testing..
Cdog
Just how delicate and calibrated would the device need to be in order to give an accurate reading? Could the calibration and measurement environment be certified? Doubtful. To beat this all you need to do is just drive with the windows slightly down bringing in plenty of fresh air. Alcohol concentration...0%.
bergamot69
Can this system tell the difference between alcohol on the breath, and alcohol emitted from freshly applied deodorant or perfume? And what about alcohol hand wipes? Frankly another irritating 'nanny device' that will most likely waste a lot of police time by having them stop law abiding citizens when they could actually be doing something useful to fight crime.
BZD
Considering how dangerous drunken idiots are on the road I am all for this technology. Of course it should be used sensibly, but just like pointing a radar at a car I can see no wrong with trying to check for a drunk driver. @Anne Ominous and VirtualGathis. Seems to me neither of you have thought this through. The majority of drivers are alone in their car and for sure even more people do not have spilled alcohol or vomit in their cars thus the doubt thing is a non-issue in many scenarios that are easily ruled out. And even for those cases where there is perhaps doubt I'd gladly risk getting pulled over for a check when being the designated driver after a party as opposed having drunken idiots behind the wheel.