Methodology and Guidelines for Regulating Traffic Flows under Air Quality Constraints in Metropolitan Areas (UTCM 08-35-17)

This project developed a methodology to couple a new pollutant dispersion model with a traffic assignment process to contain air pollution while maximizing mobility. The overall objective of the air quality modeling part of the project is to develop a model to predict the air quality at receptor sites in metropolitan areas using traffic data from a coupled traffic model and real time meteorological data. Most of the air dispersion models in use do not have a full description of the physical and chemical processes to describe the formation and transformation of pollutants in the metropolitan areas relating to traffic flow and thus cannot provide complete information that is necessary in traffic planning and regulating. The reactive dispersion air quality model developed in this project includes a state-of-the-art gas chemistry mechanism (Statewide Air Pollution Research Center, or SAPRC, model) to predict the ozone, NOx, CO, benzene, acetaldehyde, formaldehyde and 1,3-butadine concentrations, and a complete particulate matter module with thermal dynamics to predict the concentrations of primary and secondary particulate pollutants including diesel particulate matter. With the air quality model developed in this project, traffic assignments can be conducted taking air quality into account. The air quality can be considered as a form of constraint that limits the pollutants under certain acceptable levels in parts of the transportation network. This consideration will be an added constraint in addition to the roadway segment capacity constraint in the assignment process. The air quality can also be considered as an additional objective function while assigning traffic flow in the metropolitan transportation network.