AN APPROACH TO TRAFFIC NOISE STUDIES

This paper was presented at Session 30 - Noise and Environmental Studies. Aspects of the current Country Roads Board approach to traffic noise studies are described. A review is given of the multitude of scales and indexes used in environmental noise standards and legislation. The validity of using the traffic noise prediction method given by the Department of the Environment and Welsh Office joint publication (1975) entitled 'Calculation of Road Traffic Noise' (Cortn) for hourly 1 10 and 1 10 (18 hour) predictions on Melbourne's urban streets is examined. A simple modification to predict l eq is proposed. The noise emitted by various classes of vehicles and empirical equations for predicting electric train noise are reported. Methods of quantifying the change in the noise environment from a proposed action and the subsequent assessment of these changes are also discussed. It is concluded that: (a) the l 10 (18 hour) index provides a satisfactory basis for traffic noise assessment; (b) predictions from the cortn model are in good agreement with Melbourne's measured urban traffic noise; and (C) assessment of road proposals involves quantification of noise levels and qualitative assessment based on a knowledge of community values (a). (TRRL)