Monitoring the environmental impact of individual vehicles in a traffic flow

In the project MOVE, SINTEF has tested different methods to measure the environmental impact of individual vehicles in a traffic flow. One of the methods to measure the noise levels is to use a microphone array. An array with up to 8 microphones has been tested, together with a special algorithm for processing of the microphone signals. A simulation, based on measured pass-by sounds of vehicles, showed that it was feasible to acoustically separate two cars with a separation time of less than 1 second, at a speed around 70 km/h, using only 4 microphones.A commercial available traffic registration system has been used, to measure the speed of the vehicles, lane position and a classification up to 8 different vehicle categories. During the test program, the pass-by noise level of more than 4000 vehicles has been measured. The tests showed that the monitor system could identify some vehicles with very high noise levels; more than 100 dB at speeds around 60-80 km/h. In addition to monitoring of the noise levels, a new laser gas detection device has been tested, which showed that it was feasible to measure abnormal CO levels of random passing vehicles.