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Task 3.3-Travel Demand Forecasting While the final model selection will be made in Task 3.1, it is anticipated that the GCAG(VTA) model is the most likely model appropriate for use on this project. This assumption is due to the available model horizon years and that it is the adopted regional TDF model for the study area. Therefore, CONSULTANT anticipates coordinating with the Santa Clara Valley Transportation Authority regarding the modeling required to support the traffic analyses. To insure that the model reflects the current planning in the area, an initial step is a review of the land use and network assumptions in the C/CAG model for the area surround the project. The land use assumptions will be reviewed for consistency with the City's recent General Plan and Downtown Specific Plan as well as new projects that are being planned near the interchange area, such as the Inner Harbor Plan. The traffic analysis zones and roadway network will be reviewed to determine the adequacy of the network to represent the travel patterns in the project study area. The review will determine if there is a need to modify the assumptions for either the construction year or design year prior to generating future travel demand forecasts for the no project and project alternatives. While the alternatives analysis will consider up to five interchange designs, it may not be necessary to perform model runs for all five alternatives. Depending on the ramp configurations of the alternatives, there may be some cases where one model run may be sufficient to cover multiple alternatives. In these cases, manual adjustments to the ramp and intersection volumes may be used to reflect subtle differences in the ramp connections that a regional model may not capture. Therefore, it may not be necessary to prepare individual model runs for all five alternatives. Subtask 3.3.1- Coordination on Initial Regional Model Runs CONSULTANT will coordinate with VTA to prepare initial travel model runs using the existing interchange configuration for the baseline model year, construction year (2020) and design year (2040). The coordination will include a review of the model inputs related to land use and the model network. Once any modifications are made to the model, runs will be made for the baseline and two horizon years. These runs will reflect the no project conditions. Subtask 3.3.2—Review VTA Model Results CONSULTANT will review the initial model results to validate how they compare to the existing traffic volumes in the study area. Validation will focus on the peak hour and peak period traffic volumes. If there is a need to adjust the input assumptions, CONSULTANT will work with the VTA to validate the model within the project area. Model runs for the design alternatives will occur in conjunction with the Alternatives Analysis (Task 3.4). The netwark assumptions for these model runs will be developed based on the design concepts considered by the project team. Some alternative model runs could be performed early in the alternative analysis to test major interchange ramp modifications. The alternatives would the proposed in the Maple Street Split Diamond concept and the Veterans Flyover concept. The early models would be used in the Alternative Analysis evaluation to understand the future changes in travel patterns with these major configuration changes. ATTY/AGR/2013.164/URS PROFESSIONAL SERVICES AGR REV:10-15-13 VR Page 26 of 78