The Greenest Path: Comparing the Effects of Internal and External Costs of Motor Vehicle Pollution on Route Choice and Accessibility

Abstract

On-road emissions are a dominant source of urban air pollution, which damages human health. The "greenest path" is proposed as an alternative pattern of traffic route assignment to minimize the costs of emissions or exposure, pursues an environmentally optimal. The framework of a link-based emission cost analysis is built for both internal and external environmental costs and applied to the road network of the Twin Cities Metropolitan area based on the EPA MOVES model. The greenest (internal/external) path is skimmed for all OD pairs to compare the work trip flows on the roads and accessibility distribution. It is shown that the emission cost that travelers impose on others is greater than which they bear. Considering only external emissions costs thus produces a lower accessibility than considering only internal emissions costs. This research contributes to understanding the full cost of travel.