UrbanSim

1. UrbanSim Integrated Land Use, Transportation, and Environmental Simulation Alan BorningDept of Computer Science & Engineeringand Center for Urban Simulation & Policy AnalysisUniversity of WashingtonJoint work with Paul Waddell & other faculty, staff & students

2. Using Models in Urban Planning • Integrated land use and transportation models can provide an important tool for exploring policy alternatives and possible urban futures • What if …? • We built a new light rail line, and added significant connecting bus service? • We established an urban growth boundary and zoned for increased density and mixed-use, with the goal of promoting transit-oriented development? • We built a network of new freeways and widened feeder arterials? • Analogy: SimCity, but with requirements for realism • Unfortunately, models in standard use are inadequate

3. UrbanSim • Highly interdisciplinary project at the University of Washington • Participation from faculty and students from many schools and departments • Paul Waddell, project director (Evans School of Public Affairs) • Alan Borning, co-director (Department of Computer Science & Engineering) • Major funding from the Digital Government program, National Science Foundation • Additional funding from Puget Sound Regional Council, Environmental Protection Agency, plus other federal, state, and regional agencies

4. UrbanSim (2) • The system is fully operational and documented, and is distributed under an open source license (GPL) via our website www.urbansim.org • Used experimentally in Honolulu, Hawaii; Eugene, Oregon; Salt Lake City, Utah; Houston, Texas, Paris, France; Tel Aviv, Israel • First major application to a public planning project starting this summer in Puget Sound region (Seattle and surrounding metropolitan area)

5. Outline • UrbanSim inputs and outputs • UrbanSim system design • (Very brief!) Our software engineering methodology • Current work on enabling citizen access to UrbanSim’s results and simulation capabilities • (If time allows) Value Sensitive Design theory and methodology

6. UrbanSim Input Data – Integration Process

7. 150 Meter Grid Cells 150 square meter grid cellsGreen Lake neighborhood, Seattle

8. UrbanSim – System Design • Modeling: • Provide interacting component models that represent different agents and processes in the urban environment • Component models loosely coupled (for software engineering reasons); communicate via a shared database • Dynamically simulate annual time steps • Example component models: • Residential Location • Employment Location • Land Price • Real Estate Development • Demographic transition • Travel (external model)

9. Example Model - Residential Location • Households that need to be placed in new locations in a given simulated year: • Existing household predicted to move by Household Relocation Mode • New households from Demographic Transition Model • Available housing to move into: • Units vacated by households that moved out • New housing from the Real Estate Developer Model • Residential Location Choice Model places these households in available housing

10. Residential Location Model (2) • A probabilistic model • Outcome: which grid cell the household moves to • Influences on choice include: • Household characteristics (income, age of head, number of children, race, etc) • Characteristics of available housing (cost, type, neighborhood land use mix and density, access to neighborhood employment, travel time to central business district, etc) • Calibrated to local data for the region being simulated • Database takes care of accounting for where household is located, which units are occupied, etc

11. Software Engineering - Extensive Testing

12. Indicators • Indicators provide the principal mechanism for summarizing results from the simulations for different stakeholders • Indicators can be computed for various geographies (the region as a whole, cities, neighborhoods, grid cells, etc) • Examples: • Population density • Average household income • Acres of vacant developable land

13. Example simulation output: Map-based indicator display forPuget Soundregion

14. Results fromSalt Lake City:comparing predicted land prices in 2030 for the adopted Long Range Plan with a no-build alternative

15. Aside regarding indicators and the workshop theme • National Infrastructure for Community Statistics: a proposed web-based utility that facilitates access to detailed, current community-level statistics • What if we also facilitated access to selected community-level statistics for the next 30 simulated years for various possible scenarios of the future?

16. More Direct Support for Public Access and Deliberation • Three interrelated projects: • Indicator Browser • A web-based system for browsing through scenarios and indicators • Indicator Perspectives • Organizations with widely differing views on land use, transportation, and the environment analyze and comment on indicators and scenarios • U-Build-It • Planned system to give direct access to the simulation to citizens and elected officials

17. Indicator Browser • Web-based chooser for selecting scenarios and indicators to example • Dynamic generation of output • Ready-to-hand documentation • Documentation is linked directly from chooser • Live documentation – includes: • Actual SQL code to compute indicator • Test cases for SQL code

18. Indicator Browser – Live Documentation

19. Balancing Freedom from Bias with Value Advocacy • Wanted to describe why a given indicator was important to different stakeholders • We found this very difficult to do within relatively neutral technical documentation • Approach: also provide Indicator perspectives • Allow organizations or groups to present their own perspective on which indicators are important and why, and how to interpret them • In early stages - two prototype perspectives developed so far

20. Indicator Perspectives – Initial Partners • Northwest Environment Watch • an environmental group • Washington Association of Realtors • a business association • King County Budget Office, Benchmark Program • a government agency

21. Indicator Perspectives - Example

22. U-Build-It • Would like members of advocacy groups, business associations, and motivated citizens to be able to construct their own scenarios to be simulated • But UrbanSim is quite complex • Approach: a web-based system that will provide a rich set of component parts that can be mixed and matched to assemble a scenario to be simulated • User chooses among various alternatives (3 alternatives for a light rail system, 4 zoning alternatives, etc) • System assembles these into a scenario and (if not simulated already) puts this in a queue to be run • Results to be available via the Indicator Browser

23. Value Sensitive Design • An approach to the design of technology that accounts for human values in a principled and comprehensive manner throughout the design process • Central to our work on more direct support for public access and deliberation • Primary developer of VSD: Batya Friedman, Information School, University of Washington

24. Value Sensitive Design Contributions • Principled basis for considering value issues in the design of a technological system • Actively design the technology to support particular values (rather than engaging in a retrospective critique) • Methodology explicitly designed to consider: • Potentially diverse user population • Both direct and indirect stakeholders

25. Applying VSD to UrbanSim – One Example • How do we deal with the multitude of strongly held and often conflicting values held by different stakeholders? We distinguish: • Explicitly supported values • Stakeholder values • Explicitly supported values are not the same as the personal values of the designers – they are subject to a principled analysis of arguments for their inclusion

26. Explicitly Supported Values • These are taken as given, and are explicitly supported by the system as well as possible • Principal values: • Support for democratic process • Provide infrastructure that allows users to articulate and investigate values that are of greatest importance to them • Fairness (and specifically freedom from bias) • As far as we are able, do not privilege one mode of transportation, policy, etc over another • Transparency

27. Example Stakeholder Values • Clean air • Economic growth • Housing affordability • Individual property rights • Low taxes • Open space preservation • Social equity • Transportation options for disabled people • Walkable neighborhoods

28. Stakeholder Values (2) • Stakeholder values may be in conflict • A particular choice or weighting of these values should not be built into the system • Being able to answer questions about certain stakeholder values may have significant design implications (e.g. biodiversity)

29. For more information UrbanSim project website: www.urbansim.orgContact information: Alan Borning borning@cs.washington.edu