Representative spectrum of road traffic noise

Abstract

The representative spectrum of traffic noise is expressed in terms of the normalized A-weighted sound pressure level, δLn. Assuming that the traffic noise annoyance is measured by the time-average sound level, the dependence of δLn upon the traffic speed and the percentage of heavy vehicles has been derived. For traffic without heavy vehicles, an increase in traffic speed causes δLn to decrease at low frequencies. The presence of heavy vehicles destroys the dependence of δLn upon the traffic speed and may increase the value of δLn a few decibels at low frequencies.