The work carried out by Ayesa involved the major roads belonging to the Spanish National Road Network in the Community of Madrid, these spanning some 450 kilometres in length.
This had three objectives, namely to ensure compliance with European and Spanish legislation in this area; to provide assistance in terms of managing noise issues that these roads cause for the surrounding areas; and to generate data in order to establish the noise easement.
In order to describe the noise produced by these roads, four types of maps were produced: a noise level map, a map of the affected area, a noise zoning and building constraints map and a conflict map.
These maps were calculated using CADNA-A (version 4.2), which uses the French method NMPB-96 in order to obtain the sound levels detected by receivers located within the vicinity of the roads.
The study did not only determine the noise levels produced by the roads in question, but also analysed the noise caused by the infrastructures themselves. It also obtained data on the urban areas exposed to the various noise levels and included an initial proposal for reducing them.