Updated traffic noise map method based on speed cluster

Abstract Traffic noise maps are an important instrument for environmental education and research; these maps directly show the traffic noise distribution in a determining area and period. Traffic conditions and the sound pressure of a road stretch changes over time, meanings that the initial map might conflict with the perception of traffic noise by city dwellers; hence, it is necessary to constantly update these maps. A method to obtain an updated traffic noise based on a speed cluster is proposed in this study. The updated method comprises three steps: First, road stretches of the initial map were classified based on the road design guide and each category was clustered according to the speed of the road stretches that was considered to draw the initial traffic noise map. Then, the sound pressure level of all road stretches was updated using data from two steps. The first step contained few noise measurements and the speed data of all road stretches, including the current data. The second step included the predicted sound pressure level of all road stretches and speed data from the initial traffic noise map. Finally, the equivalent noise levels of all receiving points were updated using the law of sound propagation to complete the process of updating the initial traffic noise map. The accuracy of this method was validated in a case study in the Chan Chen district of Foshan, China. In this case study, the mean hourly error between the sound pressure level of all the road stretches calculated by the updated method and extracted from traffic data was 0.16 dB. The updated method can rapidly revise the sound pressure level of road stretches, making it useful in developing traffic noise maps.