We already have devices which detect vehicles that are exceeding the speed limit, or that are too noisy. Now, scientists are working on an unmanned sensor that could be used to sniff out automobiles that are emitting overly-dirty exhaust.
Being developed by a team at Austria's Graz University of Technology (TU Graz) as part of the European CARES (City Air Remote Emission Sensing) project, the sensor incorporates a two-tined tuning fork. Those tines are initially set to vibrate utilizing laser pulses. When airborne particles in the exhaust of passing vehicles subsequently pass between the tines, those particles become excited by the vibrations, causing each one of them to produce an audible signal.
The greater the number of particles present, the louder the "sound" produced by the exhaust will be. If the sensor is combined with a camera that captures the license plates of the vehicles, then human users could identify which individual cars, trucks, or motorcycles are exceeding permissible emissions levels.
It is hoped that the sensors will be ready for production by the end of 2022, at which point plans call for them to initially be installed alongside roads in CARES-affiliated cities such as Milan, Prague and Kraków.
"We want to monitor vehicle emissions in cities and environmental zones under real conditions without having to intervene in the free-flowing traffic," says Alexander Bergmann, head of the Institute for Electronic Sensor Systems at TU Graz. "The aim is to use the measurements to determine the emission class of each individual vehicle."
Owners of offending vehicles could subsequently be ticketed, have their vehicles seized, charged an ongoing vehicle-use toll, or barred from entering environmentally-sensitive areas.
Source: TU Graz