ResolutiontoAdopt20YearTransportationPlan

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Before any adjustments to the Kittitas County model parameters were made, they were justified either through the collected travel pattern data or the judgment of PTV America and their experience with transportation planning models and travel conditions throughout the model area. Model Forecasts The fourth and final step to modeling is future scenario travel forecasting. With a working calibrated transportation planning model, different land use and/or roadway projections can be entered to produce forecast results on the roadway network. Before the actual forecast can begin, this question must be raised: Are the rules established in calibration still applicable to future scenarios? Only professional judgment can answer this question. Most rules that are questioned will involve the roadway characteristic assumptions (speed, capacity, number of lanes, etc.) and should not require any model re -calibration. To complete the forecasts, the appropriate link, node, land use and/or through trip table file is changed by entering the future scenario data. After the forecast evaluation is complete, it is possible to make recommendations for the study area and test each recommendation to analyze its effectiveness on the roadway network. VISUM can compute link volume changes due to modifications in capacity, land uses, roadways, etc. These types of VISUM tools are a valuable resource for decision makers and transportation professionals in determining the most effective solutions for mitigating existing and potential roadway congestion. For this study, different sets of proposed improvement projects were coded into the model and tested. Each of these scenarios was evaluated with Kittitas County Staff. Furthermore, Kittitas County Staff was trained in use of the model so future alternatives can be rapidly evaluated. Kittitas County, Washington Transportation Model — May 2009 Page 8