Laser system scans moving cars to identify drunk drivers

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Researchers from the Military University of Technology in Warsaw, Poland have developed a laser device that can detect alcohol in cars. The remote-sensing laser system, described in the Journal of Applied Remote Sensing, scans passing cars at a distance and alerts police in real-time when alcohol is detected; providing further support for the campaign against drink-driving.

The system uses a method known as stand-off detection, where a laser is used to identify chemical and biological compounds at a safe distance from people. The authors of the research paper, Jarosław Młyńczak, Jan Kubicki, and Krzysztof Kopczyński of the Military University of Technology, noted that this detection method is already popular for the detection of chemicals, but because of advances in laser technology in recent years, the choice of possible lasers for this application have broadened, such as ‘eye-safe’ microchip lasers.

‘We all are already familiar with laser instruments used by the police for speed-limit enforcement,’ said Marco Gianinetto of the Politecnico di Milano, an associate editor with the journal. ‘Now these researchers have demonstrated how a laser device could be effectively used for detecting drunken drivers and thereby helping to reduce the number of accidents caused by drivers under the influence of alcohol.’

In order to detect alcohol in moving cars, the laser system is positioned on the side of the road to monitor each car that passes by. If alcohol vapour is detected in the car, a photo of the car, including its number plate, is transmitted to the police, who can then take further action by stopping the car and checking for signs of alcohol using conventional tests. According to the authors, these capabilities will, ‘surely decrease the number of cars that have to be checked by police and, at the same time, will increase efficiency of stopping drunken drivers.’

The system is also clever enough to recognise situations whereby passengers have been drinking but the driver has not, or if alcohol had been spilled in the vehicle.

The team tested the device by placing it next to an open window in the laboratory and scanning a moving car on the nearby road. They also established the concentration of alcohol vapour that would come from the breath of somebody drinking excessively by evaporating a water solution of alcohol of an appropriate concentration and at an appropriate temperature. The scientists discovered that the presence of alcohol vapours was detected at concentrations of 0.1 per cent and greater.

The system is also capable of identifying when drivers are trying to trick the device. ‘From the practical point of view, there seem to be some countermeasures, such as driving with windows open, solar screens on the side windows, etc., that can be applied by drivers to deceive the system,’ the authors noted in their conclusion. ‘However, such situations are very easily detected by the system, which sends this information to the policeman indicating that the car should be checked.’

These situations, along with other factors such as driving with air-conditioning or fans, will be investigated in the next stages of the ongoing project, as well as working on developing a commercial device that is that is more compact, robust and user-friendly.

In the future, this type of technology could be developed further to be able to detect other chemical compounds in order to detect drivers under the influence of different intoxicants.