Activity-Based Travel Demand Models: A Primer (2014) / Chapter Skim
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Pages 133-142
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From page 133... ...
131 SHRP 2 C10A JACKSONVILLE, FLORIDA, AND BURLINGTON, VERMONT Objective The primary objective of the SHRP 2 C10A project was to make operational a regional-scale dynamic integrated model and to demonstrate the model's performance through validation tests and policy analyses. The model system was designed to capture changes in demand, such as time-of-day choice and peak-spreading, destination, and mode and route choice, in response to capacity and operational improvements such as signal coordination, freeway management, and variable tolls.
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132 Part 2: ISSUES IN ADOPTING INTEGRATED DYNAMIC MODELS SYSTEMS activity locations to paths on a second-by-second basis for a full travel day. The network includes detailed information regarding the operational characteristics of the transportation facilities that may vary by time of day and by vehicle or traveler type such as the number of lanes; the lane use restrictions; traffic controls, signal timing, and phasing plans; turning restrictions; and tolls and parking fees (Resource Systems Group et al.
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133 Chapter 5: CASE EXAMPLES As noted in the SHRP 2 C10A final report, "Configuring DaySim to generate temporally, spatially, and behaviorally detailed travel demand information for use in TRANSIMS was straightforward, as was configuring TRANSIMS to generate the skims for input to DaySim. More sophisticated methods of providing TRANSIMSbased impedances to DaySim, such as implementing efficient multistage sampling of destinations (and corresponding impedances)
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134 Part 2: ISSUES IN ADOPTING INTEGRATED DYNAMIC MODELS SYSTEMS Model System Design and Components The SHRP 2 C10B model system comprises three primary components: DaySim, Dynus-T, and FAST-TrIPs. DaySim is a travel demand forecast model that predicts household and person travel choices at a parcel level on a minute-by-minute basis.
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135 Chapter 5: CASE EXAMPLES detailed network performance skims, as well as the ability to more precisely characterize the location, extent, and duration of congestion (T. Rossi, personal communication, Oct.
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136 Part 2: ISSUES IN ADOPTING INTEGRATED DYNAMIC MODELS SYSTEMS with sufficient detail to consider lane-level modeling. The SF-CHAMP activity-based model generates demand for the entire San Francisco Bay Area region, while the DTA Anyway model implementation covers San Francisco County only.
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From page 139... ...
137 Chapter 5: CASE EXAMPLES proved to be invaluable when applying the model to evaluate project alternatives. An additional data-related conclusion was that it is much better to use actual data rather than synthesized data, to the greatest extent possible.
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138 Part 2: ISSUES IN ADOPTING INTEGRATED DYNAMIC MODELS SYSTEMS investments in transit are being made by the region, and there is a tremendous focus around planning and developing high-capacity transit corridors. In order to have sensitivity to these strategies, it was determined that a more detailed network model than found in the trip-based demand model would be required.
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139 Chapter 5: CASE EXAMPLES used in the SHRP 2 C10A project. The model uses a temporal resolution of 15 minutes for network pathbuilding, and a temporal resolution as fine as 0.1 seconds for the simulation step size (D.
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140 Part 2: ISSUES IN ADOPTING INTEGRATED DYNAMIC MODELS SYSTEMS in travel demand forecasting practice, as both agencies intend to move toward more fully integrated dynamic model systems with future model development efforts. However, these case examples also illustrate issues (e.g., integration strategies and computational resource requirements)
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