Evaluation of a traffic demand management strategy to improve air quality in urban areas

Congestion not only has an effect on the network efficiency, but can be linked closely to roadside and background air pollutant concentrations. However, there have been very few studies that have assessed and quantified the impact of different traffic demand management strategies (TDMS) to reduce pollutant concentrations in air quality management areas. This study, funded by the DETR designed, implemented and evaluated a gating strategy upstream of a series of congested junctions which are within a street canyon, in the city of Leicester, UK. The evaluation of the TDMS involved a two month monitoring campaign, covering the period before and after implementation. Traffic flow characteristics, carbon monoxide levels, background levels and meteorological conditions were simultaneously recorded. This study has brought together the achievements of several years of research carried out by the iC research team developing measures and methods for evaluation, congestion identification and linking air pollutant levels with traffic related emission sources.