Did the Implementation of Low Emission Zone in Glasgow Change the Traffic Flow and Air Quality?

Abstract

This paper investigates how Glasgow's low-emission zone (LEZ), introduced in 2023, affected traffic patterns and nitrogen dioxide (NO2) concentrations at two sites. Using Open APIs data from the pre-LEZ (Aug-Sep 2022) and post-LEZ (Aug-Sep 2023) periods, a Wilcoxon test revealed that on High Street, significant decreases in traffic flow were observed on core weekdays (W = 359, p \< 0.001) and other weekdays (W = 122, p = 0.03), as were significant decreases in normalized NO2 levels across all day groups (p \< 0.001). Hope Street also showed significant NO2 reductions across all day groups (p \< 0.01), despite no significant change in traffic.