Milan dynamic noise mapping from few monitoring stations: Statistical analysis on road network

One of the main objectives of "Dynamap" project is to realize a dynamic noise map within a given area of the city of Milan, containing about 2000 road arches, by using approximately 20 continuous measuring stations. This map is scheduled to be updated dynamically within a period of time varying from 5 minutes to 1 hour. The ability to obtain reliable maps within a complex urban context is linked to the fact that the vehicle flow patterns are very regular. In the first phase of the project, we monitored nearly 100 roads for a period of at least 24 hours. Then, these roads have been aggregated by means of a cluster analysis, depending on their noise level profiles. The analysis of the distribution of a non-acoustical parameter in the clusters, such as the vehicular flow rate, allowed to attribute a specific noise profile to a road not present in the database. It was also possible to select the most representative arches, among the 2000 arches to be mapped, where the monitoring stations will be installed. It was finally estimated the error associated with the noise levels of the dynamic maps as a function of the updating time interval.