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[NTC2016-MU-R-03] A National Model for Predicting Life Cycle Costs and Benefits of Intersection Control Alternatives

Daniel Findley, Mark Franz
North Carolina State University, University of Maryland
Subject Area: 
Collaborative Research


In alignment with the theme, “Strategic Transportation Policies, Investments and Decisions for Economic Competitiveness,” this proposed project is designed to optimize the allocation of public funds for transportation improvements by creating a computational tool that enables agencies to efficiently compare the life cycle impacts of intersection control type alternatives. Unlike related tools used nationally, this web- based engine will calculate variables such as delay, safety, and other long-term costs and benefits within one platform.

Due to their geometric configuration, Two-Way Stop Controlled (TWSC) intersections can be associated with traffic safety and operational problems as volumes increase to unmanageable levels. As a result, transportation agencies across the nation regularly convert TWSC intersections to other configurations, in particular roundabouts, traffic signals, and all-way controlled (AWSC) types. Each of these has advantages and disadvantages that result in unique costs and benefits to the public. However, transportation agencies are challenged to monetize and compare the life cycle impacts of each because of the complexity of measuring their outcomes.

Compared to TWSC, all three of these alternatives have been shown to reduce collisions; however, the degree of reduction can vary significantly not only by control type, but also by location type (urban, suburban, or rural) and state. Conversion to an AWSC intersection can reduce collisions with only minimal construction and maintenance costs; but, can result in increased delay as volumes increase. Signalization can reduce delay to side street movements; however, may require higher construction, maintenance, and operational costs. And roundabouts often require significant initial construction costs but can effectively reduce delay if the right conditions exist (Han, Li, and Urbanik, 2008; Jiang, and Yu., 2012; Sides, Seals, and Walwork, 2005; FHWA, 2004; FHWA, 2010).