Acoustic modeling of road vehicles for traffic noise prediction: Determination of the sources heights

For traffic noise predictions road vehicles can be modeled by point sources. When dealing with the evaluation of noise barrier’s efficiency or of far‐field noise, the knowledge of the sources heights is of primary importance. Their determination can be obtained from two different methods. The first one deals with an inverse fitting procedure performed on experimental excess attenuation results between two receivers 7.50 m apart. Knowing the noise frequency spectrum at the reference microphone and the pavement and close ground impedances, it becomes possible to adjust the source height by minimizing the prediction/measurement difference. By this procedure, the equivalent noise source is found very close to the surface. Otherwise, sources heights can be obtained directly using microphone arrays. These measuring techniques are now commonly used to localize sound sources of railway vehicles. Their application to road vehicles appears to be more recent. For the present case dealing with the determination of th...