ORCA User Guide

Installing and running TransLink’s regional activity-based modeling workflow

Welcome

This guide walks you through installing and running ORCA, TransLink’s integrated regional activity-based modeling workflow. ORCA bundles five components into a single orchestrated pipeline:

• PopulationSim — synthetic population generation
• ActivitySim — residential travel demand model
• CVM — commercial vehicle model
• Quetzal — open-source traffic and transit assignment
• tlpytools (ORCA runner) — Python orchestration layer

How this guide is organized

Chapter	What it covers
1 · Setup	First-time installation on a Windows machine — clone the repo, build the five Python environments, run a smoke-test scenario.
2 · Running the Model	Initialize a scenario, run it locally, find the outputs and logs, and tune which steps run via orca_model_config.yaml.

Start with Setup if this is a fresh machine; jump straight to Running the Model if your environments are already built.

The appendices are component-specific helper guides — reference material you dip into as needed, not part of the linear walkthrough:

• Appendix A · PopulationSim — synthetic population generation
• Appendix B · Quetzal — traffic and transit assignment

Note

This is a living document. Each chapter renders from the matching .qmd source under chapters/ — see the project README.md for how to preview the guide locally or contribute a new chapter.