translate input assumptions into model inputs. These inputs are then incorporated into the TDM model to produce model results in step 3. As some of the changes have higher implications for the model results, different levels of model runs are defined depending on the input to be changed: • For the demographic assumption changes, a full 4-step model 2 run is carried out by NCTCOG. As one of the main drivers of TDM, any major changes in the population and employment assumptions would affect trip generation, distribution, and therefore final travel patterns and congestion. • To review the impact of network changes, only a traffic assignment 3 (last step of the 4-step model) is performed. Spot infrastructure changes would likely not affect overall trip generation and attraction but primarily affect trip routes, and congestion results, which are captured in the traffic assignment. • The transit strategy is defined as a planning-level strategy, and therefore, no specific routes, transit corridors, capacity and operational characteristics are defined at this point. For this reason, a post-processing step of the trip tables is carried out to reflect the benchmarked mode shares around capture areas when such strategies are incorporated (detailed methodology can be found in Section 6). Once the adjusted trip tables are estimated, a traffic assignment is carried out. The final two steps of the methodology involve the development of comparable Key Performance Indicators (KPIs) that reflect roadway network performance at both the citywide and Core Area levels and allow for comparison across scenarios. Section 7 describes the future scenarios evaluated, while Section 8 presents the resulting KPIs and other travel demand model outputs used to assess system performance. Together, these results inform project prioritization and help identify additional long-term infrastructure gaps. 4 Demographic Scenarios The methodology for the demographic scenarios follows a tiered approach, first starting with comparison of the City of Fort Worth’s growth trends with other major cities and benchmarking the downtown and Central area/ Core Area neighborhoods. Next, the planned and proposed developments in the Central area are incorporated into the future development at the TAZ level and compared with COG’s 2050 forecasts, which will be referred to as the Baseline scenario. Both these exercises, the benchmarking and Central Area planning efforts build the 2050 baseline scenario to create the alternative Acting Our Size (AOS) demographic scenario as shown in Figure 2.
2 The full model run takes about 2 weeks between input preparation, run time and review by NCTCOG. 3 The assignment run takes about 2-3 days between run time and review.
www.MovingaMillion.org | transportation@fortworthtexas.gov page 7
Made with FlippingBook - professional solution for displaying marketing and sales documents online