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Analysis of the contribution of each pass-by noise source to the overall pass-by noise is an important issue for reduction of pass-by noise. A technical approach for analyzing pass-by noise is used to identify the principal noise sources of the pass-by noise in this study. Wave propagation theory and decoupling tests are employed and the near-field measurements are carried out to obtain the characteristics of each noise source. Since the Doppler phenomenon causes a frequency shift during a pass-by noise test, the Doppler correction and time delay effects are incorporated into the estimation of pass-by noise. Combining the entire data from the action of the prior tests, a simulation program was developed for analyzing each noise source contribution and predicting the overall pass-by noise as a function of the vehicle location. Finally, the developed program can furnish an indepth understanding of the effect of each noise source to pass-by noise.