This road network is constituted by 11 single carriageways with two lanes characterized by low to medium traffic flows (the Annual Average Daily Traffic AADT of the network is about 4100 vehicles with a maximum value of 9375). The whole length of the road network is 231.8 km.
The activities were carried out using a standard methodology agreed with the U mbria Region, including noise and traffic flow monitoring, sound propagation simulations and noise mapping. Data concerning traffic flows were obtained by the traffic measurements. Three one-week long acoustic measurements were performed and the results were compared with those coming from noise simulations in order to estimate the accuracy of the modelling activity. The evaluation of the noise emitted by the roads under investigation was performed with the software SoundPLAN version 7.1 using NMPB Routes 96 as noise propagation model. The difference between noise simulations and measurements was at most 1,6 dB(A) and generally lower than 1 dB(A).
The residential and noise-sensitive buildings for which the simulated façade sound pressure levels are higher than the limits require an acoustic mitigation and are called “critical buildings”. More critical buildings can be grouped in a “critical area” if they can be acoustically rehabilitated using the same noise abatement measure.
The methodology allowed to individuate the anti-noise measure for each critical area or noise-sensitive building affected by the road network under study. A ranking of priority of the anti-noise measures was done and the costs of the actions were determined.
