Noise pollution is one of the central problems of urban areas, and its more precise characterization is the condition to set up policies to contrast it more effectively. Improvements in vehicles and roads are important, but the strategic challenge is to tackle it more effectively with a global policy. The aim of the research is a first definition of alternative noise indicators, in respect to those proposed by legislation, that should be able to better characterize the acoustic climate in urban environments and to support a more sustainable transport planning. The methodology proposed in this paper foresees the definition of a set of “standard sites”, which are a combination of simple characteristics of the section like the number of lanes (and, hence, the road width), the presence of trams, and the shape of the surrounding elements (presence or not of buildings: U or L section or free field). These parameters were chosen as the first factors to be used in the determination of the factorial plan to select the standard sites through the design of experiments and in these ways study the effects of the mobility in a “certain” area having a “shape” defined by the vicinity of the noise source (transport system: road, tramway, railway). Then, we present an application of the above classification to the urban ambit of two Italian cities, Torino and Vercelli. The methodology has been tested through a survey focused to measure, at the same time, the traffic, the noise and the people perception. The aim has been to build a data base containing all the factors influencing the noise level and the people annoyance, useful to carry out the statistical analysis allowing the precise characterization of the site and finding the cause-effect principle in the noise production and perception. Some first results concerning the effectiveness of the site selection, the selection of the variables involved in noise production and dispersion and human perception and a first indication about the noise indicators are given. The analyses on hourly ranges showed the “number of sound events greater than 70 dB(A)” as a possible representative indicator for the people disturbance if compared to the hourly equivalent sound pressure level (Leq). This implies that the mean energetic level is not so performing in describing the disturbance, but information on the “quality” of the noise event are necessary too. (Author/publisher)
Samenvatting