The Study of Mathematical Model for Predicting Road Traffic Noise

Deriving a mathematical model for A-weighted equivalent level produced by road traffic is presented. It is based on the supposition that the distribution of vehicles on the road is describable using a Poisson distribution and that vehicle sound emission is non directional (monopole). These conditions are affirmative if the traffic flow is lower than about 500 vehicles/h and vehicle speed is higher than 30 km/h. Equations are supplied for application of the model to one and two lane road. A series of measurements have been carried out on different roads to verify the model. The relationship between the calculated and measured data has been quantified using a linear regression with a resulting correlation coefficient of 0.97. An extension of the model is proposed to include situations when the vehicles move at a speed slower than about 30km/h. In such situations the noise emission of a single vehicle is supposed to be directional in line with the direction of motion (dipole). The differences between monopole and dipole models are also studied.