On the perception of Limited Traflc Zones as urban noise mitigation action

Environmental noise is a very important issue in modern urban agglomerations and new policies are being explored in order to reduce high sound-pressure levels from transportation and industry, especially in urban contexts. Considering this issue from the subjective perspective, environmental noise is often related to noise annoyance. Over the years, possible solutions were explored for urban sound planning beyond the mere noise control engineering techniques and a number of international projects proposed innovative approaches to deal with this issue: most of them were traffic-related. In order to support the city management, it is suitable to analyse possible indirect effects of traffic limitations on the perception of the sonic environment. Indeed, it was observed that even traffic management plans with no specific focus on noise mitigation are likely to have acoustic implications. The present study investigated the variations of the sonic environment induced by the implementation of a Limited Traffic Zone (LTZ) in the historic centre of Naples, in terms of objective parameters and perceived quality of the ‘sound’ component by means of noise and social surveys before, immediately after and one year after the LTZ implementation, in order to check for possible time effects. Results show that the sample interviewed immediately after the LTZ implementation reported overall positive opinions on the sonic environment and its variation, while the sample interviewed one year after tended to shift to more neutral opinions. This finding suggests that the LTZ could be considered an effective environmental strategy for the urban noise control, but it should be adequately actuated in order to preserve the achievements in terms of noise reduction and subjective perception by the local population.