Variability of traffic noise pollution levels as a function of city size variables

Noise levels measured in 27 cities with different areas (from 0.6 km2 to 59.27 km2) and populations (from approximately 2000 to 70,000 inhabitants) were compared with respect to five different urban characteristics (population, area, total street length, density, and linear density). Comparisons were conducted for both overall city noise levels and noise registered on five types of roads with different functionality using the Categorisation Method. The results showed that four of the five cities’ characteristics presented a significant correlation with the noise levels (all except for density). The calculated correlations were better for noise levels in the different categories than the overall noise values, with higher explained variability on the streets with more traffic. Therefore, the road categorisation method can be used not only to assess the noise variations within cities, but also to better explain the effect of noise on the analysed city characteristics. The results of the calculated relationships enable the estimation of noise levels both currently and in future urban developments of noise values on different types of streets. [Display omitted] •The categorisation method and city size variables explain most of urban noise.•Linear models predict urban traffic noise with standard errors lower than 2.2 dBA.•City size variables explains the noise variability in road categories by up to 86%.•Linear density explains noise variability statistically similar to size variables.•Surface population density is a poor descriptor of urban noise variability.