Quantification of Pass-by Noise Levels on Urban Roads: Effect of Engine Propulsion and Tire–Road Interaction

Abstract

Vehicle speeds frequently fluctuate due to the prevailing heterogeneous traffic conditions on Indian roads. Accordingly, traffic noise levels are affected by different noise sources that depend on various vehicular and roadway characteristics. In order to simulate the actual vehicle noise generation at the possible speeds on Indian roads, an integrated method has been developed in this study to quantify the engine and tire–road noise levels. The governing parameters considered for the pass-by noise quantification include vehicle speed, type of pavement and gear shift/gear transmission. The measured A-weighted noise levels [LAmax (dB)] revealed that tire–road noise levels increased with the rise in vehicle speeds irrespective of the vehicle type and type of the pavement. Further, the tire–road noise levels quantified through the new methodology closely matched the noise levels measured by the standard coast-by method. The cross-over speeds for engine propulsion noise and tire–road interaction noise occur at much lower speeds on the cement concrete pavements compared to the asphalt pavements. On a decisive note, the perspective of measuring the roadside noise levels coupled with an engine propulsion noise measurement as reported in this study is first of its kind and can be used for noise measurements on critical urban roads by priming with the conventional pass-by methods.