A CRITICAL ANALYSIS OF SKETCH-PLANNING TOOLS FOR EVALUATING THE EMISSION BENEFITS OF TRANSPORTATION CONTROL MEASURES. INTERIM REPORT

The role of transportation control measures (TCMs) in the transportation planning process has increased since the passage of the 1990 Clean Air Act Amendments. TCM analysis began in the early 1980s and several sketch-planning tools are now available. The two premier sketch-planning tools used for evaluating transportation control measures are the Systems Applications International (SAI) method and the San Diego Association of Governments (SANDAG) method. Both methods were adapted to an available spreadsheet for easy use and modification. The SAI method required full programming in the spreadsheet, whereas the SANDAG method, originally developed for spreadsheet use, required only minor revisions. A critical analysis, base scenario comparison, and sensitivity analysis were performed on the SAI and SANDAG methods. Results of the sensitivity analysis showed that the tools are most sensitive to the scope descriptors and work-related variables. The report concludes that (1) recent work in the field has greatly advanced the state-of-the-practice; (2) the SAI method proved to be a better analysis tool than the SANDAG method; and (3) although sketch-planning tools are gross estimating techniques, they are currently the best TCM analysis tools.