A critical analysis of sketch-planning tools for evaluating the emissions benefits of transportation control measures

Abstract

The role of transportation control measures (TCMS) in the transportation planning process has increased since the passage of the 1990 Clean Air Act Amendments. Transportation control measure 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 conclusions of the thesis are: recent work in the field has greatly advanced the state-of-the-practice; the SAI method proved to be a better analysis tool than the SANDAG method; and although sketch-planning tools are gross estimating techniques, they are currently the best TCM analysis tools. The principal recommendation is for further development of the SAI method. Supplemental recommendations are made for further development of specific areas: integration with emissions factor models; incorporation of modal emissions analysis; development of tools to assist in determining peak period travel information; development of latent demand and indirect trip effect estimation procedures; development of procedures for estimating TCM participation rates; evaluation of synergistic, additive, and negative effects of TCM programs; and validation of results obtained from sketch-planning tools.