Within-Day Dynamic Estimation of Pollutant Emissions: A Procedure for Wide Urban Network

Road vehicle emissions are an important aspect of the life quality and sustainability. Recent studies show that traffic flow-speed profiles and vehicular emissions are related. The increase of congestion leads to in an increase of pollutant emissions and, moreover, emissions are sensitive to different drivers behavior. In this context, it is possible to reduce vehicle pollutants emissions, decreasing congestion with traffic planning policies and on-line operations. The aim of the paper is to obtain reliable values of pollutant emissions in a wide urban network, taking into account the within-day variations of traffic conditions and parameters related to the different state of vehicles (congested and uncongested conditions such as the queue length, the average speed of vehicles in the queue, the length of the link travelled at free-flow speed and so on). The developed within-day dynamic emission model has been applied to the city of Brindisi (Italy) and the estimated emissions have been compared with the results of standard macroscopic approach in order to quantify the differences. Finally an analytical model to compute emissions at signalized intersections is presented.