UDST develops and maintains open-source software for urban simulation, transportation and accessibility analysis, workflow orchestration, and discrete-choice modeling.

• UrbanSim — urban-development and regional simulation methods and model components
• Orca — in-process orchestration for analytical and simulation workflows
• ChoiceModels — discrete-choice specification, estimation, sampling, and simulation
• Pandana — established network accessibility and shortest-path APIs, maintained for compatibility
• UrbanAccess — integrated transit and pedestrian network-data preparation

See the project directory for current status, mission, and reference architecture.

UDST is resuming active maintenance of its core open-source projects. Current priorities are tracked in the UDST Maintenance Revival project.

Contributions and participation in project maintenance are welcome. Please consult the organization-wide contribution guidelines and the guidance in each repository before beginning substantial work.

UDST projects provide open methods, interfaces, and self-managed reference implementations within defined technical scopes. UrbanSim Inc. separately provides commercial products and services, including prepared data, operational model implementations, managed computation, visualization, and continuing support.

See Open-source projects and commercial offerings for the full policy.

UDST grew from a long-running program of research in urban simulation, transportation, accessibility, and planning. Its development was supported by the National Science Foundation, the Environmental Protection Agency, other public research sponsors, planning agencies, and many academic collaborators.

See Research support and acknowledgments for the principal awards, institutional partnerships, and later publicly sponsored research that contributed to this work.

Paul Waddell founded UrbanSim and owns and stewards the UDST GitHub organization. UrbanSim Inc. administers the organization and supports repository maintenance.

GitHub organization ownership is distinct from copyright in individual contributions. Each repository remains governed by its published open-source license.

See the History of UrbanSim and UDST, the Governance policy, and the Credit and attribution policy.