Congestion Evaluation Best Practices

Traffic congestion can be evaluated in various ways that result in very different conclusions about the nature of the problem and optimal solutions. This paper describes various factors that affect congestion costing and the evaluation of potential congestion reduction strategies, including the scope of analysis, baseline speeds, travel time unit costs, the impacts of traffic speeds on accident and emission rates, consideration of induced travel impacts, and consideration of co-benefits. It discusses how these factors influence planning decisions, and describes best practices for comprehensive evaluation of congestion impacts. It applies this comprehensive framework to evaluate various congestion reduction strategies including roadway expansion, alternative mode improvements, pricing reforms, smart growth policies and demand management programs.