A new analytical method for the calculation of outdoor noise propagation

A new analytical method for the prediction of road traffic noise propagation (called MAPB in French) is presented. This method answers the need of a simple calculation tool usable in the new standard that is being elaborated in France. From the Fresnel zone concept and from simplifications of Weyl-van der Pol's theory and Geometrical Theory of Diffraction (GTD), new expressions of attenuation due to the ground as well as that due to different barrier types are developed. The complete model in a homogeneous atmosphere (MAPB-H) is obtained by combining these expressions using a classical geometric method. For the case of an atmosphere with a small constant sound speed gradient, the use of corrective length and height terms gives the complete formulation of the MAPB-F (for a positive gradient favourable to propagation) and the MAPB-D (for a negative gradient unfavourable to propagation). Turbulence is neglected in this approach. MAPB-H is validated using a numerical Boundary Element Method (BEM). MAPB-F and MAPB-D are validated with the help of a mixed Rasmussen-Brekhovskikh numerical method, as well as with outdoor measurements. Comparisons of results obtained with the MAPB and those obtained from numerical methods and measurements show good agreement. (C) 1998 Elsevier Science Ltd. All rights reserved.