A soundscape approach to analyze traffic noise in the city of Taipei, Taiwan

Traffic noise has been a serious issue in urbanized areas and caused annoyance and health problems. It is thus essential to monitor and reduce traffic noise Traditional approaches focus on the measurement of amplitude or frequency of noise. Nonetheless, these measurements hardly help researchers distinguish unique features of dominant noise at different types of land use. This study adopts the theoretical framework of urban soundscape to examine noise patterns. Amplitude, frequency and time, are three key parameters for the analysis of soundscape. Sound recordings are made at four urban sites (downtown, one commercial, and two residential areas) in the City of Taipei, Taiwan, during three time periods (8 am, 3 pm, and 8:30 pm). Sound data is processed by seewave and XLSTAT software for the representation of spatiotemporal patterns of urban soundscape. Principal Component Analysis (PCA) approach is introduced to analyze the dominant sources of noise under various types of land use. The analytical results intuitively explain how various types of vehicles play vital roles under different types of land use. For instance, cars or taxis are the dominant sources of noise in residential and commercial areas in the afternoon and evening. The results also specify the dominance of public transport such as buses in the downtown areas during daytime. In summary, the adoption of the descriptive soundscape pattern and computer-based statistical analysis in this study helps researchers not only understand the relation between traffic noise and urban landscape but also develop a conceptual framework to reduce impacts of noise and improve the quality of life in cities.