Ecoflex: improving air quality with green dynamic traffic management based on real time air quality measurements

Across the world, air quality regulations are breached due to localized high pollution episodes in specific locations, or "hotspots". Advances in air pollution monitoring techniques enable hotspots to be identified more effectively; however challenges remain as to how best to reduce the incidence and impact of these episodes. Where road traffic is the dominant source of pollutants, ITS measures, including alternative traffic management strategies, may be deployed to mitigate the hotspot and contribute towards regulatory compliance. This paper demonstrates how the real time local air quality is used as input for a dynamic traffic management system. Based on the current state of the air quality, the traffic management strategy will be adapted in order to improve the local air quality real time in an urban environment. An environmental trigger signal is developed based on the local black carbon concentrations. The trigger decides when to switchthe traffic light control system from the standard control scenario during good air quality to the EcoFLEX control scenario when the air quality is below a certain threshold. This scenario decreases the average queue lengths and number of stops at the intersection for motorized traffic and increases the average speeds, which are all favorable for reducing emissions. EnViVer simulations show an emissions reduction in EcoFLEX mode of 8.2% for NOx. The EcoFLEX system makes hotspot mitigation possible since it is possible to control the air quality locally by adapting the traffic control system, only when necessary.