Research advance review of the highway traffic noise source and its intensity evaluation model

The paper is dedicated to a research advance review of the highway traffic noise source and its intensity prediction model.As is known,with the fast development of China's economy,all kinds of car vehicles have become a major tool of daily living,particularly in the urban life. Traffic noise and its adverse impacts on the surrounding environment attract ever-increasing attention both from home and from around the world. Here we would like to review traffic noise evaluation models,which were made based on the constant driving speed experiments in the 1950 s,in which a single vehicle sound pressure level can be taken as noise unit for assessment on the roadside. The estimated levels were then expressed as functions of vehicle type and speed,and with zero acceleration. Meanwhile,algorithm models were used for predicting the equivalent continuous level and peak level at a certain distance from the roadside were also developed to evaluate the source intensity of the traffic noise. Still later source intensity models were developed to evaluate the equivalent continuous level under the interrupted and varying flow conditions. Most of such evaluation models assumed that the traffic noise is made from the single point source,while some others took it as a short line source; and still others believed they were made with different spectra. Based on a review on the development of the intensity assessment models of the traffic noise,we have conducted a in-depth comparative analysis among the commonly used models,including FHWA,CoRTN88,RLS-90,MITHRE,StL-86,ASJ-1993 and that were used in China,from their characteristic features,the estimation methods,and the ranges for application. The current problems with traffic noise evaluation may include( 1) the intensity assessment of traffic noise,which only includes the vehicle types and speeds,but fails to reflect the effects of traffic flow,the road building material,slopes,road width,and the surrounding conditions on the assessment results,and( 2) the determination,prediction,and assessment of the traffic noise are all mainly made based on the continuous equivalent level and peak level,which fail to reflect the real effects of the traffic noise on the surrounding environment.Thus,the present review can probably be used to serve as a reference to the prediction and evaluation of the highway noise in China even in the future.