Non-responsiveness of conventional measures of road traffic noise to an urban truck restriction strategy

Abstract

This study reports the acoustic results of heavy vehicle restrictions on an urban road corridor. It is not the traffic strategy itself that is the focus of this paper, but the insensitivity of conventional measures of road traffic noise to the resultant changes in heavy vehicle flows, and hence to assessing the effectiveness of the heavy vehicle strategies in reducing noise exposure and human response to noise. Community reaction to noise from heavy vehicles is a major constraint in urban freight management and the effects of control strategies must be able to be measured. Heavy vehicle management on an urban corridor in Brisbane, Australia, lead to a measureable reduction in their flows. Noise monitoring, nine sets of measurements over 30 months, showed no change in conventional measures of road traffic noise (LA10 and LAeq). However, the level and incidence of the maxima of pass-by noise events in the traffic stream did show a change. If human reaction to road traffic noise depends only on the conventional measures of noise, there is no issue. If, as the literature suggests, effects such as sleep disturbance depend critically on the number and level of noise events, conventional traffic noise measures provide an unresponsive set of indicators on which to base, and assess, heavy vehicle management strategies.