Laser System Detects Drunk Drivers
5 June 2014
A laser system detecting alcohol vapors in a car from a safe distance has been developed by scientists at the Military University of Technology in Warsaw, Poland.
The system uses a single-mode laser with a wavelength of 3.39 micrometers and power of 2mW, placed on one side of the road and pointed at a mirror on the other. The beam is piloted by an additional 0.6 micrometer wavelength laser, which (after being reflected back by the mirror) is guided into a detector linked to a specially developed electronic system for analysis.
Because the beam goes through the car two times, the absorption by the alcohol vapor is increased. Using a water-alcohol solution at a temperature similar to that of a human body, the scientists were able to simulate vapors from a lung in a moving car. The system was proven to be precise enough to detect the presence of a person with alcohol concentration of 0.1? or more in their blood.
Having detected alcohol vapors, the system takes a picture of the vehicle and its license plate and sends it to a police officer down the road who can stop the car and test the driver with traditional methods. Researchers point out that the system will likely detect vapors in cases when passengers, but not the driver, have been drinking or when alcohol has been spilled in the car.
But it will still be of great benefit for law-enforcement, because it will decrease the number of cars that have to be checked, allowing police to catch drunk drivers more efficiently. In the future, similar methods for detecting drugs and other intoxicants may be developed as well, the researchers say.