Economics of Travel Demand Management: Comparative Cost Effectiveness and Public Investment

Document Type


Publication Date


Subject Area

planning - travel demand management, land use - planning, ridership - demand, organisation - management


Accuracy, Benefit cost analysis, Cost effectiveness, Decision making, Economics, Investments, Sketch planning;, Travel demand management


The 2006 Congestion Mitigation and Air Quality Improvement (CMAQ) Program Interim Guidance provides explicit guidelines to program effectiveness assessment and benchmarking by calling for a quantification of benefits, as well as disbenefits, resulting from emission reduction strategies for project selection and evaluation. The objective of this study is to develop a methodology that combines academic and practitioner experiences within a theoretical framework that truly captures consumers’ price responsiveness to diverse transportation options by embracing the most relevant trade-offs faced under income, modal price and availability constraints. The development of the theoretical model leads to the design and implementation of TRIMMS (Trip Reduction Impacts for Mobility Management Strategies), a practitioner oriented sketch planning tool. TRIMMS permits program managers and funding agencies like the Florida Department of Transportation (FDOT) to make informed decisions on where to spend finite transportation dollars based on a full range of benefits and costs. The approach is consistent with other benefit to cost analyses. Its accuracy and the perceived fairness are critical when significant funds are at stake. The model allows some regions to use local data or opt to use defaults from national research findings, select the benefits and costs of interest, and calculate the costs and benefits of a given program. A step by step introduction to the program, its capabilities, and a set of working examples to guide the user through the process of evaluation is included in the report. A key strength of this model is its wide range of benefits and costs that can be selected for the analysis. The model’s flexibility and robustness allows it to be adopted by agencies throughout the country. Future research could seek to enhance the model to include more of the internal benefits to employers (e.g., changes in worker productivity, reduction in overhead, changes in employee retention, etc.). A byproduct of this research effort that goes beyond the initial project objectives is the development of a structured approach to evaluate the impact of soft programs. Compared to the currently available soft program evaluation methods, the approach developed in this report provides a less heuristic method of estimation resulting in statistically robust mode share impact predictions. Another future area of analysis would be the refinement of such models to provide a standardized approach to soft program impact assessment.