Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
54 C h a p t e r 9 This project successfully demonstrates viable local methods for estimating reliability measures, as well as the economic value of travel time reliability within a context of transporta- tion decision making. The principal research activities included (1) increasing policy makersâ situational awareness through workshop engagement, (2) obtaining a value of travel time reliability that was locally acceptable for the demonstration needs of this project, (3) applying such a value to an integrated regional TDM and dynamic traffic and transit assignment modeling approach, (4) setting up and evaluating a wide range of sce- narios, and (5) presenting the research findings to the same policy groups and obtaining feedback and comments regard- ing the overall modeling exercise and assessments of potential future use of reliability in actual project analysis. The Metro policy group adopted a simplified stated- preference method via an online survey to estimate a reli- ability ratio that could be used to estimate the value of travel time reliability. Although this method is highly simplified, the estimated reliability ratio appears to be comparable with findings in the literature and was confirmed to be acceptable for further project scenario modeling activities. To better account for the time-varying nature of traffic dynamics and to further leverage prior SHRP 2 research products, the research team applied state-of-the-art network models to capture the needed sensitivity with respect to reli- ability. The research team integrated Metroâs trip-based TDM with the dynamic traffic assignment model DynusT and dynamic transit assignment model FAST-TrIPs. Both of the latter models were based on research products associated with the SHRP 2 C10B project. SHRP 2 L35A is the first project to demonstrate successfully the feasibility of integrat- ing the network models from SHRP 2 C10B with a trip-based model. More than 10 scenarios were identified and modeled in this project. The analysis results indicated that both bus rapid transit and VMSs would contribute to improved reliability for the Southwest Corridor when considering the perfor- mance over multiple modes and facilities. Bus rapid transit contributes to improved corridor performance by increased ridership due to higher reliability, and VMSs contribute to improved corridor reliability by balancing the arterial and freeway flow via information dissemination. Such modeling processes and results were fully presented and discussed at the second workshop with the Metro policy group. The policy group members concluded that incorporat- ing reliability into the overall scenario and project analysis helped them better understand the potential benefit of studied strategies that could not be realized by using the traditional method. The research team and the policy group also concluded that a more comprehensive and rigorous survey method with a sufficient number of correspondents will be conducted for the Metro region to establish a value of travel time reliability that can be used in future project selection and policy making. Multiple paradigms exist for estimating the reliability measures. In addition to L03, an alternate method that can account for more detailed local recurring and nonrecurring data is the Monte Carlo simulation type of method proposed by SHRP 2 L04. The L04 method is applicable to small net- works, but it is not useful for a large region due to computa- tional intractability. Lessons Learned and Concluding Remarks
