This past Summer, the Tri-Agency Team has shifted gears away from estimating a route choice model with observed data towards and “assert and calibrate” approach. This shift was motivated by our desire to have a model ready for application at the end of this project and informed by both a more detailed review of the observed data as well as our investigation into methodological challenges of dynamic passenger route choice estimation. We are not leaving these challenges behind, but rather forking the project into two prongs so as to not put solving them on the critical path to having a model that is ready to use.

The “Applications Track” of work is focused on standing up the Fast-Trips model such that it can be used in projects by agencies. This track’s plan, as denoted in the memo Developing and Applications-Ready Route Choice Model, is to first develop a set of performance targets and calibration tools to allow the team to efficiently identify and remedy issues. Subsequently, the plan is to complete three phases of calibration. Phase I focuses on making sure Fast-Trips makes sense at the individual trajectory level when compared with the on-board survey and California Household Travel Survey GPS data. Phase II will then scale this to full Bay-Area Fast-Trips runs and comparisons to route level and screenline-level validation data. Phase III will include a full Bay Area validation when integrated within the SF-CHAMP travel demand model and run with feedback.

The “Research Track” of the workplan will focus on defining and prioritizing the problems at hand for researchers and developing a set of test cases that researchers might use in order to explore the problems and validate any solutions. This work, which is detailed in the Memo Research Track Workplan, will be undertaken in conjunction with researchers in the field in order to more accurately understand the methodological gaps and more meaningfully frame a roadmap for remedying them.

We have spent the past Fall completing work on the performance targets and calibration tools and working through the Phase I calibration as described in the memo as well as a procurement to create a bench of researchers who will comprise our research advisor panel for the research track. We look forward to sharing the Phase I calibration process and what we have learned thus far in a forthcoming post.