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cost-effectiveness in the TRB/CMAQ study. Conversely, bicycle facilities appear relatively cost- effective for emissions reductions in the California studies summary, while appearing 2/3 of the way down the TRB/CMAQ cost-effectiveness ranking. Finally, referring back again to the previously described Seattle I-5 corridor TDM-impact analysis, the CORSIM traffic simulation of conditions in the 8.6-mile study corridor produced emissions impacts with and without the 2003 TDM programs at the 189 CTR-participant employers. It was estimated that, absent the CTR-based TDM programs, AM and PM peak-period HC emissions would increase by a total of 38.1 kilograms, representing a 10.3 percent increase in the AM period and a 13.1 percent increase in the PM period. Estimated peak-period CO emissions increases would total 2,654.3 kilograms, a 9.6 percent increase in the AM and a 12.7 percent increase in the PM. Similarly, NOx emissions would increase by a peak-periods total of 122.2 kilograms, an 8.9 percent increase in the AM period and a 10.9 percent increase in the PM period (Georggi et al., 2007). ADDITIONAL RESOURCES Many of the other chapters of this TCRP Report 95, "Traveler Response to Transportation System Changes" Handbook constitute additional resources for TDM. More specifics are provided in the introduction to this chapter's "Overview and Summary" section. Additional resources external to TCRP Report 95 include the following materials. FHWA TDM Report, Practitioner Manuals, TDM Model, and Website Resources Perhaps the most comprehensive set of research and guidance materials on employee-focused TDM is still the report series titled Implementing Effective Travel Demand Management Measures, prepared by Comsis and the Institute of Transportation Engineers (ITE) in 1993 for the Federal Highway Administration, with support from the Federal Transit Administration. The set of materials in this series includes: A main report with the following three sections (Comsis and ITE, 1993): Part I--A basic "Introduction to Travel Demand Management," including an overview of strategies, terminology, application environments, and expectations for impact. Part II--An "Inventory and Review of TDM Measures," with detailed information on 11 cate- gories of strategies, including improved alternatives (transit, carpool, vanpool, and bike/ pedestrian improvements); incentives and disincentives (complementary support measures, HOV priority treatments, economic incentives, parking supply and pricing, and tolls and con- gestion pricing); and alternative work arrangements (variable work hours, compressed work weeks, and telecommuting). Included for each strategy is a description of its various forms, when and where it is most appropriately used, how it achieves its impact, other strategies with which it is or is not complementary, examples in application, ranges of potential impact, imple- mentation issues, and additional references. Part III--A "Synthesis of Findings" that first introduces empirical findings from a sample of TDM programs, analyzing and discussing them in a manner to help reveal those features that are most critical to success. An analytic tool, the TDM Evaluation Model, is then presented as a means of estimating combined effects of TDM strategy packages applied in different travel 19-137

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settings. The model is used to create tables and graphs that indicate ranges of impacts of each strategy across different levels and settings. Cost-effectiveness is then explored, and guidance is provided to assist in design and implementation of real-world TDM programs. A set of three Practitioner Guidance Manuals, also prepared for FHWA but published and dis- tributed by the Institute of Transportation Engineers (ITE): Implementing Effective Employer-Based Travel Demand Management Programs, A Guidance Manual. For employers or professionals designing employer TDM programs, this manual provides an introduction to TDM, objectives, review of strategies, and recommended steps to take in design- ing and implementing a program. There is a worksheet section where the user is led through a program design, in which tables and charts are provided to ascertain the impact of the particu- lar set of strategies selected (ITE, 1993). Areawide Travel Demand Management Programs, A Guidance Manual. This resource provides sim- ilar guidance in understanding and designing alternative TDM programs, but from the per- spective of either a public agency or an area-wide organization such as a TMA or transportation district. This manual incorporates both employer-side measures and area-wide measures such as those that a public agency might initiate (ITE, 1992a). Marketing Research for Transportation Demand Management Programs, A Guidance Manual. Provides special guidance on how to obtain the appropriate data and conduct the proper analyses to better ensure that the right strategies are chosen in relation to characteristics of the particular market. Covered are market research methods, research questions and information needs, information gathering techniques, data analysis methods, and special calculation forms and a look-up table as aids for applying the marketing research results (ITE, 1992b). An FHWA public-use version, with accompanying User's Guide, of the Comsis TDM Evaluation Model. FHWA offers contemporary TDM information through its "Travel Demand Management" webpages at http:/ / and the "Travel Demand Management Toolbox" found therein. The report, Mitigating Traffic Congestion: The Role of Demand-Side Strategies, linked through the "Publications and Reference Materials" section of the toolbox, places TDM in a broader context of demand-side strategies. This report provides an overview discussion of each type of demand-side strategy along with 26 case studies (Association for Commuter Transportation et al., 2004). Center for Urban Transportation Research Resources The National Center for Transit Research at the Center for Urban Transportation Research (CUTR) at the University of South Florida maintains a highly active program of research and analysis ded- icated to Transportation Demand Management. The following is a list of reports, references, or services of interest. Economics of Travel Demand Management: Comparative Cost Effectiveness and Public Investment. This 2007 project developed a methodology that combines academic and practitioner experiences within a theoretical framework that aims to capture consumers' price responsiveness to diverse transportation options by embracing the most relevant tradeoffs faced under income, modal price and availability constraints. This work may be accessed at 19-138

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Development of the theoretical model led to the design and implementation of Trip Reduction Impacts for Mobility Management Strategies (TRIMMS), a practitioner-oriented, sketch-planning tool. The spreadsheet, which includes elements for estimating the effects of the "soft" marketing and support strategies, is available for download at Impact of Employer-based Programs on Transit System Ridership and Transportation System Performance. This is the full 2007 report on the Seattle I-5 TDM impact analysis covered in the "Related Information and Impacts" section under "Site- Versus System-Level Impacts"--"End Results of Dissipation." It includes description of the analysis methodology and can be accessed at National Smart Transportation Archive Researcher. The National Smart Transportation Archive Researcher (NSTAR) was developed to make available an online, updatable, easily searchable database of case studies documenting effective use of TDM strategies to reduce VMT and SOV mode share. The database is intended for use by transportation professionals and worksite employee transportation coordinators to develop and improve the effectiveness of their own pro- grams. The database is located on the Help Desk of the National TDM and Telework Clearinghouse at The accompanying Best Practices Guide features 12 in-depth case studies of some of the more effec- tive worksite trip reduction programs. These particular worksites are located in Washington State and reflect a mandatory regulatory environment requiring employers to participate and produce results. The case studies were developed from data of the Washington State Department of Transportation's Commute Trip Reduction Program along with interviews with worksite employee transportation coordinators. The Best Practices Guide is available at http:/ / tdm/pdf/NSTAR.pdf. Over 100 employer case studies may be viewed at http:/ / helpdesk/casestudies.htm. State and Regional Program Reports A series of evaluation reports developed for the Los Angeles County MTA TDM Demonstration Program provide not only information on the range of VMT, air quality, and cost impacts of a wide range of TDM strategies, but also serve as a practical guide in methods of empirical evaluation. While the vast majority of TDM or TCM measures are designed and implemented with little or no data gathered on their net effects, this study is exemplary in the careful application of before- and-after evaluation data collection methods, by far the most reliable way to assess travel and other impacts when many internal and external variables are at play. See in particular the MTA Transportation Demand Management Evaluation Final Report (Comsis and Pansing, 1997) and the MTA TDM Demonstration Program Third-Party Evaluation Final Report (Comsis et al., 1996) The Washington State Legislature created a trip reduction performance program in 2003 to encour- age entrepreneurs, private companies, transit systems, cities, non-profit organizations, developers, and property managers to provide services to employees that result in fewer vehicle trips arriving at worksites. The final report for 20032005 contains case studies with before-and-after data. It is found at 0/20032005_CTR_ProgramReport.pdf. The Washington State DOT Commute Trip Reduction (CTR) Program 2005 annual report notes that employee drive-alone rates, vehicle trips, and VMT to CTR worksites have decreased signifi- cantly. However, it also notes that progress toward the program's statutory goals has been variable. 19-139

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See CTR_Report_05.pdf. A related web document highlights the extent that public dollars are lever- aged with private (employer) dollars invested in CTR: funding.htm#impacts. Other Information Sources TCRP Report 87, "Strategies for Increasing the Effectiveness of Commuter Benefits Programs" (2003) may be accessed via the_Effectiveness_of_Com_152144.aspx. Marketing tactics and messages are suggested in the course of addressing means to promote effective programs. Appendix D, Table D-6, has a list of approximately 40 employers who offer commuter tax benefits to employees, along with their par- ticipation rates. The Victoria Transport Policy Institute (VTPI) Online TDM Encyclopedia, developed and actively maintained by the VTPI, is a comprehensive resource on a wide range of transportation manage- ment strategies (Victoria Transport Policy Institute, 2009). The Encyclopedia is a truly "online" resource, accessible at, and offers a high degree of flexi- bility in searching for and extracting information on TDM. The Encyclopedia describes a large number of TDM applications and contains information on TDM planning, evaluation, and imple- mentation. Hyperlinks provide access to more detailed information, including case studies and reference documents. The Online TDM Encyclopedia has an international perspective, with ideas and examples from across the world. VTPI, the creator and supporter of the Encyclopedia, is an independent research and consulting organization located in Victoria, British Columbia. Canadian government resources include the Transportation Demand Management Database, found at http:/ / Included are profiles and results for 92 projects worldwide, focused on sustainable development, energy efficiency, accessi- bility, and increased productivity. A good summary of TDM experience in the Netherlands and in the United Kingdom is provided by the British study Smarter Choices--Changing the Way We Travel, prepared for the Department for Transport (DfT) (Cairns et al., 2002). Analytic Tools One of the earliest tools still in use is the TDM Evaluation Model. It was developed by Comsis Corporation in the early 1990s from a combination of empirical TDM research studies and tradi- tional transportation planning logit mode split models. The original purpose was to supplement the conventional "four-step" metropolitan travel forecasting process when performing corridor, subarea, or even regional transportation impact studies involving TDM alternatives. Voluntary and mandatory employer participation rates are taken into account. The TDM model is generally applied to regional forecast trip tables (base year, present year, or future), and is used to estimate the impact on mode split, vehicle trip rate, and VMT for each origin-destination pairing. The revised trip tables may then be returned to the four-step (or other) travel demand model for traffic assignment. In this manner it is possible to interpret the effects of employer TDM programs on actual facility volumes and levels of service. Model outputs may then be used for air quality analysis. The model is also a reasonably convenient way of investi- 19-140