Project Meeting 2022.05.19

Meeting Notes

Admin

• Invoicing to partners has been delayed, but expected soon.

Metropolitan Council Update

• Last year, MC set up a basic model using ActivitySim, starting from the SEMCOG model as a donor model.
• No calibration or estimation, but some basic adjustments to align with the recent TBI survey data.
• MC wants to talk with other agencies about what to do next, given their timeframe and budget for the next phase. Ideally by June.
• Performance: the model takes a day and a half, two days to run.

Econometrically consistent simulation of multinomial and nested logit choices

• A proposal by @janzill with VLC in Australia. He opened this new issue #568 to discuss.
• A new method to make simulated choices would be created: instead of making one random draw from a spectrum of probability, we would make one random draw per alternative.
• In the limit for infinitely large populations, this change in theoretically meaningless, but all actual simulations have a finite population, and the change could result in practical changes.
• This feature would be activated by a settings / yaml configuration switch.
• It is expected to have little runtime implications, neither notably faster or slower than the existing system.
• The consortium generally approved of moving forward with this idea.
• Some concerns were raised about whether and how this might impact the generation of logsums for upstream components.
  • Would we (could we, should we?) pass the drawn maximum utility up to higher level models, instead of logsums? Probably not for now, but this is worth thinking about.
• Everyone is invited to post comments/questions into the GitHub issue.