THE USE AND EVALUATION OF TRANSPORTATION CONTROL MEASURES. INTERIM REPORT

The Clean Air Act Amendments (CAAAs) and the Congestion Mitigation Air Quality (CMAQ) program established in the Intermodal Surface Transportation Efficiency Act (ISTEA) mandate the evaluation of transportation control measure (TCM) emission impacts. These mandates have created an important role for the proper documentation and cost-effective evaluation of TCM emission impacts in the transportation planning process. There is currently no commonly accepted standard for monitoring or evaluating TCM impacts. This report summarizes a database compiled for this study on the use of TCMs and their documented travel and emission impacts. The entire database is also provided in the appendix of this report. The TCM evaluation methodologies currently available were also reviewed. The methods reviewed include the use of comparative empirical data, network-based models, and sketch-planning tools. Overall, it was concluded that the current database on TCM impacts is inadequate, and that the different characteristics of TCMs, and the intended (or limited) nature of their impacts, currently require the use of several methods for a complete impact evaluation. In fact, none of the methods reviewed can analyze all the TCMs identified in the CAAAs. It was also concluded that the current state-of-the-practice in TCM impact evaluation must be improved and that the use of sketch-planning tools is currently the most promising approach. It is recommended that a standardized TCM impact monitoring and data collection program be initiated in Texas and nationwide, and that sketch-planning tools, although currently the most appropriate and cost effective approach to TCM impact evaluation, still need further study and improvements to their evaluation capabilities.