Vehicles’ Noise at Sao Paulo: Composition, Problems and Solutions

Excessive noise level in urban centers is a problem which causes many health diseases and, although gaseous emissions are getting down, noise remains high and exceeds the recommended levels from World Health Organization (WHO). The first step to deal with this is the Noise Map, a software tool that represents the noise level through a color scale over a map but usually without show the reasons of such level and neither evaluating the presence of motorcycles in the composition of the traffic flow. This article analyzes the noise contribution and particularities of different types of vehicles in the traffic of Sao Paulo City and looks for solutions to a quieter environment. It was measured road traffic noise of cars, motorcycles and buses and identified the main problems that contribute to keep it high. Cars appear as the most relevant source and their tires as the main influence in the Equivalent Sound Level (Leq). Motorcycles are the second biggest source, with high Leq and many vehicles above 80 dB(A) due to non-original mufflers and buses as the third, also with high Leq and many vehicles above 80 dB(A) but with significant influence of the cooling fan.