Evaluating Unplanned Stand-Alone Transportation Projects: Linking Incremental and Comprehensive Planning

Abstract

Transportation agencies may review proposed projects that were not examined as part of the long range planning process. Typically, these projects require an immediate response and lack detailed data. This paper describes a methodology to assess such unplanned or “stand-alone” transportation projects and applies it to two case studies: a large development involving several major new highway sections and a pedestrian crossing of a four-lane arterial bisecting residential and commercial areas. The methodology specifies the trade-offs and uncertainties of the proposed stand-alone projects. For example, adding phasing to an existing signal resulted in a lower capital cost, and a lower feasibility of pedestrian use, than constructing an overpass. Yet, neither alternative assures crash risk is minimized because the extent of pedestrian compliance with traffic laws is not known. The outcome is thus a timely clarification of each alternative’s advantages which can be compared to existing policies. Limitations are the availability of site-specific knowledge, the willingness to articulate difficult choices that are clarified by this work, and the feasibility of fully considering cumulative impacts. However, by formalizing the analysis of stand-alone projects, the methodology strengthens the link between such incremental decision making and comprehensive long range planning.