A literary review of the history of the study of diffraction of acoustic waves on planes was carried out. The main methods for determining the acoustic efficiency of noise barriers are presented. A finite element model was built in the COMSOL Multiphysics software package to evaluate the acoustic efficiency of noise barriers using numerical methods. A comparison was made of the barrier insertion losses obtained by the empirical method using Maekawa’s data with the results of numerical calculations. The limits of applicability of the analytical method are analyzed.