Evaluation of tube-shaped bus shelters as a noise mitigation solution for passengers

Abstract

Environmental noise pollution, a worldwide problem, interferes in the physical and mental health of humans. Therefore, noise mitigation measures should be part of urban planning around the world. In Curitiba, Brazil, many bus shelters have a tube-shaped design. The purpose of this work was to ascertain if these tube-shaped bus shelters can mitigate environmental noise that reaches their users. To this end, equivalent sound pressure levels were measured simultaneously inside and outside 40 shelters and the Insertion Loss (IL) was calculated. The difference between the external and internal sound pressure measurements was determined statistically by means of a parametric analysis of variance (one-way ANOVA) and the nonparametric two-sample Kolmogorov-Smirnov test (K-S test). These measurements indicated that tube-shaped shelters reduced environmental noise levels, with IL varying from 2.1 to 8.9 dB(A), and an average IL of 4.9 dB(A). The one-way ANOVA and K-S significance tests, with p-values of 0.0113 and 0.0022, respectively, and with 95% certainty, indicated that IL was generated by the null hypothesis corresponding to the insertion of the tube-shaped bus shelter. Hence, it can be concluded that tube-shaped bus shelters not only enable fast passenger traffic but can also mitigate environmental noise levels.