Noise pollution control / Noise perception

Autostrade per l’Italia and its subsidiaries are carrying out a major investment plan to develop and modernize the highway network.

Noise perception

Noise is defined by the World Health Organization (WHO) as "undesired sound".

The intensity of the noise perceived is a function of sound pressure, which is evaluated using a logarithmic scale and a conventional measurement units known as the decibel.

Some examples of noise sources and the respective sound pressure levels are provided in the below figure.

Current legislation sets out that noise pollution caused by road traffic must be measured in "equivalent A-weighted noise levels" expressed in [dB(A)], namely a parameter that time-averages individual noise events caused by vehicle transit on the basis of the sensitivity of the human ear (A-weighting).