“Environmental limit values for habitat infrastructure works: the problem of the identification of parameters based on the exceptions to the law"

Noise pollution, caused by traffic, industrial activities is one of the main local environmental problems: actually, about 20 percent of the European population is highly annoyed by environmental noise. The importance of this problem has been fixed by DIR 2002/49/CE, relating to the assessment and management of environmental noise, with the aim of containing and eliminating acoustical impact caused by different sources, to improve or maintain environmental acoustical quality. Italian legislation identifies in the noise mapping, (which consists in the subdivision of a land in areas, acoustically homogeneous, where limit values are fixed) the instrument put in charge for territorial acoustical management: this instrument must be suitable with the existent acoustical conditions to allow favorable development territorial plans and an effective land management. The acoustical planning, in the case of particularly event could have a particular meaning, being not only an answer to territorial management, but also a preliminary acoustical evaluation ex ante. The noise mapping can represent a significant picture of acoustical conditions before the construction of infrastructure, such as roads or railways, to compare with the acoustical predicted impact of the new source. This research is about a study case, which aim is at first the realization of noise mapping for an Italian little town, with a project of a new road infrastructure. The noise mapping which has been done on the whole municipal territory had to confront with two aspects: a new residential urban area and a natural park as protected zone, areas with a good acoustical quality, which will be involved in the construction of a new infrastructure. In fact, the tunnel, which will connect the existing roads and highways, will have the inlet and outlet in these areas. In this research an acoustical analysis of noise mapping has been done, integrated with the new problems, induced by the road variations and by its work construction.