As the environmental quality standards for noise were revised, it becomes increasingly important to predict road traffic noise behind roadside buildings. This paper presents methods for calculating LAeq at specific individual positions behind a building directly facing a surface road and for calculating section-averaged equivalent continuous A-weighted sound pressure level (SA·LAeq) behind a row of buildings belong the road. The validity of the methods presented here is verified by model experiments. In addition, the authors analyze the relationship between the calculated values and the parameters for the calculations such as height of the building, opening ratio of the row of buildings and so on. As a result, it is shown that the calculation methods can be simplified at some positions of receivers.
The revised environmental quality standards for noise provide that the status of noise in the “areas facing roads” should be evaluated by calculating the number and the ratio of residences at which LAeq excesses the standards. Therefore calculating road traffic noise in large built-up areas becomes increasingly important. This paper presents methods for calculating section-averaged equivalent continuous A-weighted sound pressure level (SA·LAeq) in the built-up areas facing a surface street and a highway with noise barriers. In these methods, the built-up areas are classified into a row of buildings directly facing the road and the other buildings behind it. The values of SA·LAeq in the areas are calculated by summing the contributions from the sound paths propagating among buildings and over them. The validity of the methods presented here is verified by model experiments and field surveys.