Document Type


Publication Date



Transit-oriented development, Traffic congestion -- Evaluation, Traffic congestion -- Environmental aspects, Street railroads, Air quality management, Transportation -- Management -- Environmental aspects


This study seeks to quantify the effect of the University TRAX light-rail line on traffic near the University of Utah, providing quantitative data that can be used to shape future transportation policies aimed at reducing traffic congestion, energy consumption, air pollution, greenhouse gas emissions, and parking costs. Travel demand models have long been used to estimate and evaluate the effects of transportation improvements, like LRT investments, on network travel flows and times as part of long-range planning studies, using four-step models or more sophisticated urban simulation studies. However, these are usually ex ante studies. Few ex post evaluations have been done, and in this sense, the effects of transit on traffic volumes and associated energy consumption and air pollution have not been rigorously evaluated to support or refute the justification for subsidized transit. Such quantification is required for a comprehensive cost-benefit analysis. Our aim is to provide the first hard evidence of light-rail’s impact on traffic in a travel corridor, to quantify the associated savings on energy consumption, air pollution, and parking costs, and to compare cost savings to transit subsidies.


This is a final report, NITC-RR-611, from the NITC program of TREC at Portland State University, and can be found online at:



Persistent Identifier