Project Meeting 2025.04.17

Agenda

• Explicit Error Terms

Technical

• Explicit Error Terms
  • Addressing ambiguity in comparable choices between base and build scenarios
    • Team extensively discussed two broad alternatives to the current metho which seeds RN by chooser ID and model ID
      • Make RN seeds less unique
        • Not consistent with implemented MNL and NL models or observed data
        • Requires implementation of different model forms
      • Make RN seeds more unique
        • Reduces comparability between base and build scenarios even when changes are directly related to changes in systematic utility
    • Team concluded that we should hold off on further discussion until we thoroughly test the current implementation
  • What we are testing
    • MC simulation is not adequate for economic appraisals due to simulation variance
    • EET simulation is adequate for economic appraisals due to reduction of simulation variance
    • EET simulation results in more logical choice outcomes at a disaggregate level than MC simulation with respect to changes in systematic utility between base and build alternatives
    • EET simulation results in more logical choice outcomes at an aggregate level than MC simulation with respect to changes in systematic utility between base and build alternatives
  • Scenario testing
    • Sensitivity Test #1: Skim Test
      • Develop synthetic 20 mile transit corridor; decrease transit IVT and first wait time in AM and MD periods by 50% for zones within 10 miles of buffer
    • Sensitivity Test #2: Land Use Test
      • Identify synthetic employment center; double employment within buffer
      • Will not iterate with feedback, but with accessibility changes
    • Total of six runs
      • Base MC, Base EET
      • 2 Build Runs for Skim Test (MC, EET)
      • 2 Build Runs for Land Use Test (MC, EET)
    • Use SANDAG's SANDAG model for tests
      • Calibrated working model; familiar by team members
  • Model Summaries
    • Disaggregate summaries
      • Cross-tabulation of base vs build choices for each model summed across decision-makers
      • Some models are more complex due to number of choices; instead focus more on extent of shifts
      • Summaries stratified by tour purpose
    • Aggregate summaries
      • Trip tables by TAZ, Mode, and Tour Purpose
    • Scripts will be created and run for both scenarios for each simulation technique and visualized in a Quarto notebook
    • Level of effort: 107 person hours; 36 hours per scenario
  • Addressing computational efficiency
    • 56 hours for software improvements that can be done within budget
  • Propose moving forward with sensitivity testing first and then reserve budget for software improvements
  • Next update May 20
• Roadmap draft was sent out on Tuesday and will be uploaded to Google Drive
  • Comments should be completed by April 25th
  • WSP will send out a reminder mid-next week
• Explicit Telecommuting documenting is coming soon