A simulation model for urban traffic noise

Abstract

Urban traffic noise is studied by a simulation model whose main features are the following: effects of traffic lights, speed limit, possibility of vehicles overtaking, and driving styles. In the model there is a basic assumption about driver’s behavior (‘‘follow the leader’’), considering the case of straight and level road with two lanes for every carriageway, and two traffic lights. Three driving styles are considered: A (‘‘quiet driver’’): change of gear at 60% of engine speed corresponding to maximum torque, B (‘‘normal driver’’): at 80%, C (‘‘fast driver’’): at 100%. The behavior rules provide for: keeping of safety distance, overtaking if there are vehicles at different speeds, deceleration and stop at traffic lights with red, synchronization of two traffic lights, if requested. From the kinematic side, the model was validated by comparison with acceleration distribution of a real vehicle’s flow, while the acoustic one was by the comparison with noise levels measured along urban streets. The simulation model lets one take into account the following factors concerning the traffic noise emission: main noise sources of vehicle (tires, engine, intake and exhaust system), traffic flow and maximum speed allowed, traffic mix as regards different driving styles.