CONTROLLING ROAD TRAFFIC NOISE

The control of traffic noise follows two main directions. First, the noise produced by the vehicle itself can be reduced by the enforcement of stricter noise emission standards for new vehicles, requiring improvements in vehicle design. Substantial reductions in traffic noise are promised if commercial vehicle noise can be reduced to nearer 80 dba under standard test conditions. Road surface noise is arguably the most difficult component of vehicle noise since substantial reductions in its level are limited by existing constraints on tyre and road design which are needed to achieve an adequate standard of skidding resistance. The second method involves the design of roads and buildings to minimize the effects of traffic noise. Prediction techniques have been developed which enable the engineer to examine different planning options and legislation has improved the compensation code to provide sound insulation to traffic-affected buildings and to ease the burden where loss of amenity results from new road development. This article reviews briefly the progress that has been made towards the development of procedures to control and reduce vehicle and traffic noise for existing and short term development and for long term planning. The role of research carried out at the transport and Road Research Laboratory in determining suitable strategies is illustrated. /TRRL/