Aug. 29 - Acoustic engineers at EPFL in Switzerland are developing a sound tracking system they say will help regulators control traffic flow and reduce road noise. The World Health Organization says road noise is a major contributor to poor health in Europe but by monitoring traffic flow, the engineers think they can help. Tara Cleary reports.
Swiss acoustic engineers Pascal Heritier and Patrick Marmaroli's remote controlled cars may look like toys. But their purpose is serious. They're helping to test a new design; a microphone-based, non-intrusive, road traffic monitoring system. Heritier says the device can calculate three different vehicle parameters using only a computer and a set of microphones. SOUNDBITE: PASCAL HERITIER, EPFL SCIENTIST, SAYING: "We have to count the cars that are passing, take the speed of each car, and as well, the sound level that the car is making. What we can make with this system is take all these measurements at once, that is we take the speed, the sound, the number of cars." And those measurements are crucial in determining traffic noise, which according to the World Health Organization, adversely affects the health of nearly 1 in 3 Europeans The 'passive acoustic sending' system comprises a metal five-foot high stand mounted with eight microphones, all equidistant from the centre. SOUNDBITE: PATRICK MARMAROLI, EPFL SCIENTIST, SAYING: "We measure the sound at two different locations, we look at the sound discrepancy, and we return to the source. The source could be a vehicle. If we look at its position in time, we get its speed. The source could also be the wheels of the vehicle, so we can dissociate the front wheel from the back wheel, and measure what we call the wheel base, and it gives an indication of the size of the vehicle." Marmaroli and Heritier say the system is inexpensive, unobtrusive and easy to maintain. Initial tests have achieved accuracy of speed to within five kilometres per hour for 75 percent of vehicles. The duo expects those figures to improve as technology is refined -- but it may take a few more laps with those remote controlled cars.