ASPECTS OF VEHICLE AND TRAFFIC NOISE CONTROL

Road traffic noise can be reduced by reducing noise emissions at source or by interposing measures along the noise propagation path. Examples of road traffic noise control methods being used in the UK are reviewed. Source noise can be controlled by quietening the vehicles by technical improvements to the engine and exhaust. Measures to control noise emitted by the power unit are discussed with reference to the development of noise testing standards. Tyre/road noise is a major noise source. The EU has introduced a type approval test for tyre noise. The characteristics of both tyres and road surface influence noise generation. The statistical pass-by (SPB) method and the close-proximity (CPX) method for predicting tyre noise according to road surface are discussed. The noise generated by an individual vehicle is also affected by how it is driven. Noise is reduced by speed controls. Body noise is a problem associated with commercial vehicles. A guide to best practice for controlling vehicle body noise has been produced by the Department of the Environment Transport and the Regions. The use of intelligent speed limit signs has reduced traffic noise. The public perception of the effects of traffic noise controls is discussed. This paper was presented at the Umwelt BundesAmt Workshop 'Further noise reduction for motorised road vehicles', 17-18 September 2001, Berlin, Germany.