Macroscopic modeling approach to estimate traffic-related emissions in urban areas

This paper integrates a macroscopic dynamic traffic assignment (DTA) model for urban traffic flow with an instantaneous emission model to investigate traffic-related emissions in urban areas of arbitrary shape. It is assumed that homogeneous travelers continuously distributed over the urban areas tend to choose a path to minimize their total travel cost based on instantaneous traffic information. The macroscopic DTA model consists of a two-dimensional hyperbolic system of nonlinear conservation laws with source terms and an Eikonal-type equation used to describe the path-choice behavior of travelers. A solution algorithm for the model is designed as a Runge-Kutta Discontinuous Galerkin method for the hyperbolic system coupled with a fast sweeping method for the Eikonal-type equation on unstructured meshes. A case study investigating macroscopic characteristics of urban traffic flow and predicting exhaust emissions emitted by various types of vehicles in urban areas is conducted to illustrate the applicability of the model and the effectiveness of the algorithm.