Prediction and evaluation of noise pollution caused by a roads network

According to OECD, at least 20% of the European Union population (around 80 million of people) is exposed in daytime to traffic noise, whose level exceeds the limit of 65 dB(A); traffic represents today the main source of noise in most European countries. Italian laws are very concerned about noise pollution; in particular law no. 447/95 states the obligation - for companies which run public transport services and for those which run road infrastructures - to carry out noise evaluation and reduction plans. In this context, the local government of the zone of Perugia and the Department of Industrial Engineering of the University of Perugia have started a cooperation aimed at predicting, evaluating and reducing traffic noise in the whole network of the zone (about 2,800 km). The large extension of the network made necessary the use of a simulation code; a commercial code was used to study the acoustical climate produced by the road infrastructures in a conventional “impact corridor”. The code needs traffic flow data as input and is able to produce 3-D noise maps as well as developing the costs-benefits analysis of the mitigation interventions. The calibration of the code was made by comparing a significant number of noise measurements with the predicted data. Results were satisfactory in most cases, though corrections regarding traffic flow coefficients had to be introduced into the code. The final accuracy of simulations obtained is about 0.5 dB(A)