Road traffic emission monitoring on motorways

Road traffic noise is one of the major environmental noise sources that is known to cause health problems. Despite existing noise reception items, the continuing growth of traffic causes higher levels than the lims allow. Consequently, excessive costs are incurred for noise barriers along roads and motorways. It's therefore essential to investigate the options for noise abatement at the source. Road traffic noise emission has been measured at two sites in the Netherlands in order to obtain operational and statistical data during a 24-hour period. These measurements allowed to determine the contribution of various vehicle groups to the L DEN and to examine these in more detail. The results confirm that at some motorway locations, heavy trucks can have a dominant contribution to he L DEN. It was also found that not only tyre noise but also powertrain noise from the exhaust, engine and transmission can contribute significantly at around 80 km/h. New tools allow to evaluate the causes of the higher noise contribution from particular vehicle groups in normal road conditions. Not only the nominal emission from the ype est and the vehicle speed of heavy vehicles are relevant, but also the maintenance condition.