Project Meeting 2023.05.02 - ActivitySim/activitysim GitHub Wiki

Agenda

  • Road Map Update - Vision: Behavioral Representation

Action Items

Meeting Notes

  • Presentation: activitysim-roadmap-wip-behavior-02-may-2023.pptx

  • Presentation today was intended to be an overview with a follow-up discussion next week.

  • Overall representation

    • One code base with three examples
    • Consortium maintenance would be limited in scope to resident passenger travel. We would not maintain special market models (special generators, for example)

  • Examples / levels

    • Level 1: ActivitySimple
    • Level 2: State-of-the-Practice
      • Where we are today
      • 2-zone, something like the SEMCOG model
    • Level 3: ActivitySim 2.0
      • Wait until the software is improved
      • More advanced specification

  • Key Ideas for Level 3

    • Today's presentation is to discuss the trajectory and eventually want to get consensus around broad ideas and then detail implementation stuff later
    • Broad representation of constraints
      • List of examples provided in slides of different constraints that we don’t necessarily handle well today
    • Continuous representation of time
      • Desire to represent activities rather than tours, which would open up possibilities (such as which will be done at home versus require travel)
      • We probably don’t want to simulate every activity, but working or not is an important distinction.
      • Scheduling would be similar to now but gets complicated when looking at overlapping activities and multi-tasking, for example. This representation would required activity prioritization.
      • Would be easier to account for activities now taking place at home / travel substitution
    • Supply-side representation of unique attractors
      • For example, large universities in smaller to medium-sized communities
    • Non-traditional work patterns
      • This gets complex when we look at travel that could be modeled in other components. For example, does someone who travels for work (such as a plumber) be included in the passenger model or light-duty/very small trucks CV model. TNC drivers also complicates this.
    • Allocation of vehicles to travel
      • Helps to represent repositioning of vehicles
      • Requires schedules that are consistent in time and space
    • Responses to schedule stress
    • Accessibility-based sampling
      • Reduce the number of samples overall – oversample where accessibilities are changing significantly and reduce elsewhere
      • Could be done in Level 2
      • Note that this seems less behavioral and more implementation/software issue
    • Model specification GUI
      • Requires a data model
      • Likely use web-based tools
      • Longer-term idea but motivation is to make it less error prone when writing utility expressions

  • Overall comments

    • Not included in this group is allocation of fleets (supply-side issue, now mostly private fleet), for example: TNC service availability
    • Roadmap needs to explicitly identify the data requirements to implement the vision
    • Induced demand: this is the other side of the coin on constraints. The canceling of activities is related to the question about induced demand. Request to add something in the roadmap that addresses induced demand. Related is quantifying user benefits.