Traffic Assignment Considering Air Quality

This paper presents a methodology of assigning traffic in a network with the consideration of air quality. First, the optimization problem is formulated considering both the travel cost and on-road emissions. A Genetic Algorithm (GA) is then adopted to solve the complicated optimization problems with non-linear terms. This paper also introduces a cell-based approach to model emission concentrations so that either average emission or maximum emission can be considered in the optimization process. The case studies demonstrated that the traffic assignment procedure proposed in this paper can effectively reduce emission concentrations in these locations with the worst environmental conditions with only a marginal increase in travel time and average emission concentration in the entire study network.