Noise prediction of vehicle sources on freeways and arterials using measured sound data

Evaluation and mitigation of noise from vehicular sources is common as a building design criterion and has been part of the California State Building Code and HUD multi-family building design requirements since the 1970s. It is now included in Green Building Design Standards and school and healthcare facility design guidelines and is expanding to all types of buildings with the addition of the new acoustics credit in LEED version 4. These criteria require that the noise level be quantified precisely, but do not provide a method for defining the noise level given the normal variations in noise level. This paper examines the factors that should be considered when defining the exterior noise from vehicular sources. Methods for predicting the noise level using data from relatively short measurement periods are evaluated, and minimum survey requirements to determine specific exterior noise parameters are suggested.