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Innovations in Travel Demand Modeling, Volume 2: Papers (2008)

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Suggested Citation:"T57054 txt_031.pdf." National Academies of Sciences, Engineering, and Medicine. 2008. Innovations in Travel Demand Modeling, Volume 2: Papers. Washington, DC: The National Academies Press. doi: 10.17226/13678.
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through 8 is not strictly sequential but corresponds to the meaningful blocks of which the model stream is built. Some of the models (for example, Model 6, the TOD choice model) are called twice in the procedure, first for mandatory tours (after Model 2) and second for non- mandatory tours (after Model 4). Models 5, 6, and 7 are also closely connected by sharing mode- choice log sums; thus, they are implemented together for technical conve- nience and computer time savings. Model 1 is the automobile ownership model, which determines the exact number of vehicles available for each household on the basis of the household attributes and the transit accessibility level of the residence. Model 2 determines the daily activity pattern for each person. A person can either have a mandatory activity pattern, such as work or school; only nonmandatory activities, such as shopping; or no travel activity for the day. This model also determines the number of mandatory tours each per- son with a mandatory activity pattern makes during the day. After a mandatory tour is scheduled, the available time left for other travel opportunities is updated. Model 3 is unique to the MORPC set of models and determines joint travel among household members. This model allows two or more members of a household to travel jointly for a shared activity, for example, eating out. Given the high propensity of household members to travel together, this model is important in that it more accurately accounts for the characteristics of this travel, particularly in relation to mode choice. In virtually all other models in the United States, this phenomenon is not accounted for directly. Again, after joint tours are determined, the available time left for additional travel is updated for each synthesized person. Model 4 generates all individual nonmandatory tours, such as shopping, eating out, and recreation. Each tour can be scheduled only within the residual time window remaining after the scheduling of all previous tours. If no time exists for additional tours, then additional tours cannot be scheduled. The next three models are applied together and include tour destination choice (Model 5), TOD choice (Model 6), and tour mode choice (Model 7). The desti- nation and mode choice models are both logit based, and the destination choice step uses the log sum composite impedance measure from the mode choice model. The TOD model is based on the time windows concept, accounting for the use of a person’s time budget over the day. It includes the mode choice log sum for various TOD periods, making it sensitive to congestion. These models are applied at the tour level, yielding the primary destination, TOD, and mode choice for the entire tour, and consider both outbound and inbound portions of the tour. 31DEVELOPMENT OF MID- OHIO REGIONAL PLANNING COMMISSION TOUR- BASED MODEL 1. Household car ownership 2. Linked daily activity patterns for HH members Mandatory (work/university/school) Primary destination (5) TOD (6) and mode (7) Residual time windows for persons Nonmandatory (maintenance–discretionary) At home–absent (no travel) 3. Joint HH tour generation and participation of HH members 4.1–4.2. Maintenance HH tour generation and allocation to HH members 4.3. Discretionary individual tour generation 5. Destination; 6. TOD; and 7. Mode, for nonmandatory joint and individual tours 8. Secondary stop frequency, location, and trip mode choice FIGURE 1 Structure of core set of MORPC models (Columbus, Ohio).

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TRB Conference Proceedings 42, Innovations in Travel Demand Modeling, Volume 2: Papers includes the papers that were presented at a May 21-23, 2006, conference that examined advances in travel demand modeling, explored the opportunities and the challenges associated with the implementation of advanced travel models, and reviewed the skills and training necessary to apply new modeling techniques. TRB Conference Proceedings 42, Innovations in Travel Demand Modeling, Volume 1: Session Summaries is available online.

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