The minimum measurement time for estimating LAeqT of road traffic noise from the number of vehicle pass-bys

The minimum measurement time interval T needed for obtaining the effective and accurate LAeqT’s of road traffic noise at a site along a highway is discussed in this paper. Some simulation experiments based on the mathematical model proposed by authors are carried out. The influence of four kinds of traffic variables, i.e. the traffic volume, a percentage of heavy vehicles in it, an average vehicle speed, and the number of vehicle pass-bys, exerted on LAeqT and also on the level difference between LAeqT and the long time average sound level are examined. In addition, the confidence intervals for LAeqT to be measured under the fluctuating traffic conditions are referred to. How many number of vehicle pass-bys is required for obtaining a reliable LAeqT during measurement time interval T is examined by using the technique of inferential statistics.