Integrated Land Use, Transportation, and Environmental Modeling

Alan Borning, University of WashingtonMark Simonson, Puget Sound Regional Council

NSF Digital Government Case Study: UrbanSim

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 freeway or rail line?– We changed zoning or established an urban

growth boundary?– We changed the tax structure?

• What are the impacts on traffic congestion, open space, housing affordability, resource consumption, emissions, …?

UrbanSim Input Data – Integration Process

Parcel file

BusinessEstablishment

File

CensusPUMS,STF3

EnvironmentalUGBCity

CountyTraffic Zone

DataIntegrationProcess

Input Data

Jobs

JobIDSectorGridId

Households

HouseholdIDPersonsWorkersChildrenAge of HeadIncomeGridId

Data Store

Grid Cell

GridIdTotal Housing UnitsVacant Housing UnitsTotal Nonres SqftVacant Nonres SqftDevelopment TypeLand ValueResidential Imp ValueNonres Imp ValueEnviron OverlaysUGBCityCountyTraffic Zone

150 Meter Grid Cells150 square meter grid cells

UrbanSim - Interacting Component Models

Housing

Land

Macroeconomy

JobsHouseholds

NonresidentialBuildings

DevelopmentRegulations

TransportationAccessibility

TravelModel

Example simulation output: Map-based indicator display

Software Development Methodology• We use a version of an agile software

development process• Developers: 2 PhD-level software engineers,

computer science grads & undergrads• Architecture designed to make it easy to

experiment with different component models, add new models

• Test-first development, extensive battery of tests

• Mostly Java currently; increasing use of Python• Software is Open Source (GPL)

Tests, Tests, and More Tests

• 300+ Unit Tests using JUnit• 12+ Acceptance Tests using FIT (literate

tests, readable by modelers)

Applying UrbanSim in Puget Sound• Puget Sound Regional Council

– The transportation, economic and growth planning agency for the central Puget Sound region of Washington State

• Some challenges for PSRC and the region (among others)– Transportation (e.g. traffic congestion, aging

infrastructure, public transportation)– Very hard to find additional funding due to a series of

ballot initiatives and voter opposition to any tax increase– Achieving goals of state Growth Management Act, such as

preventing sprawl and loss of open space– Housing affordability, other equity concerns– Environmental issues: salmon, water quality, air quality,

resource consumption

PSRC and Forecasts• History of preparing regional and sub-

regional demographic forecasts– Federal and State obligations to maintain travel

demand forecast capability– Use of DRAM/EMPAL models to produce regular

Small Area Forecasts

• Improving land use modeling is a priority– Direct response to comments heard during

update of transportation plan, Destination 2030• Better representation of land use plans and data• Able to test policy “what if” scenarios• Expanded geographical reporting ability

UW/PSRC Collaboration

• Active, ongoing University of Washington/PSRC partnership to extend and apply UrbanSim to the region

• Major activities– Last year: data collection, preparation, assessment– Current: sensitivity analysis (experimenting with 5

alternate scenarios that test the system’s response to major policy changes)

– Spring 2005: use with realistic policy scenarios– Summer 2005: use in first major policy application

(update of VISION 2020, the region’s adopted growth and transportation strategy)

• Extensive involvement of PSRC staff, Regional Technical Forum, and others

UrbanSim Project - Future Directions

• Additional ecological models• More direct support for public

access and deliberation• A platform for open-source

collaboration among modelers?

Ecological Models• Claim: for modeling the impact of urban areas on

the environment, a behaviorally-based model of human activity is essential

• Current ecological models in UrbanSim:– [amount and spatial distribution of open space]– Land cover change (done for King County)

• Planned or likely:– Integration with EPA Air Quality model– Water demand model

• Other strong candidates:– Greenhouse gas emissions– Energy consumption– Salmon

More Direct Support for Public Access and Deliberation• Three interrelated projects:

– Indicator Browser• Ready-to-hand documentation• Live documentation; test-on-demand• Dynamic output

– Indicator Perspectives• Organizations with widely differing views on land

use, transportation, and the environment analyze and comment on indicators and scenarios

– U-Build-It• Giving direct access to the simulation to citizens

and elected officials

A Platform for Open-Source Collaboration among Modelers?• Developing UrbanSim user community

– Application in Salt Lake City, Eugene, Honolulu, Houston, Phoenix, Tel Aviv, Paris, and elsewhere

– First UrbanSim Workshop in San Antonio in January

– Please ask Charlie Schweik for a copy of his paper “Open Source and Open Content: A Framework for Global Collaboration in Social-Ecological Research”