Modeling Land Use Change in Chittenden County, VT Using UrbanSim

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Modeling Land Use Change in Chittenden County, VT
Using UrbanSim

• Austin R. Troy, PhD
• austin.troy_at_uvm.edu
• Brian Voigt, Research Assistant
• brian.voigt_at_uvm.edu

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Project Dynamic land use and transportation
modeling

• Purpose to simulate future land use,
  transportation and environmental impact in
  Chittenden County under baseline and alternative
  scenarios
• US DOT FHWA funded 2006-2008
• Collaborators Resource Systems Group (RSG, Inc),
  CCRPC, CCMPO, UVM
• Tools UrbanSim, TransCAD

Image source Above and Beyond by Alex MacLean,
Julie Campoli and Beth Humstone
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Research Questions

• What will land use patterns in Chittenden County
  look like in 25 years?
• What effect(s) will future development patterns
  have on the environment?
• How might policy and investment strategies
  influence these outcomes?

Image source Microsoft Virtual Earth
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Modeling with UrbanSim

• University of Washington
• www.urbansim.org
• Model parameters based on trend analysis
• Integrates market behavior, land policies,
  infrastructure choices
• Simulates evolution of households, jobs and real
  estate development
• agent-based for household and employment location
  decisions
• grid-based for real estate development decisions

from Waddell, et al, 2003
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The Four Ds of UrbanSim

• Dynamic
• Disequilibrium
• Different time scales
• Disaggregated

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UrbanSim Decision Makers
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Household and Employer Activity

• Occupancy / Vacancy
• Transition
• Mobility
• Location
• options
• decisions
• Development is based on supply of and demand for
  additional units / area

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UrbanSim Model Architecture
data store
model output
modified from Waddell et al., 2001
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UrbanSim Model Architecture

• Suite of sub-models
• land price
• accessibility
• transition
• mobility
• location choice
• Development
• User specifications
• model interval one-year time step
• sub-model order and frequency
• schedule of TDM runs

from Waddell, et al, 2003
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Exogenous Inputs Control Totals

• Externally derived inputs
• Model does not predict demographic / ecnomic
  changes
• Spatially allocates changes to population /
  employment
• Many estimates ultimate source to be determined

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Model Output

• Output database defines grid cell state
• Graphics
• maps
• charts
• tables

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Indicators

• Predefined indicators
• transport VMT
• land use vacancy, non-residential sq ft
• land value
• households income
• population density
• Environmental
• watershed function
• habitat fragmentation

Image source Microsoft Virtual Earth
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Using a Simulation Model for Comparative Scenario
Analysis

• What is a scenario?
• Alteration of model inputs/ assumptions from
  baseline
• Types of changes that can be assessed
• Zoning
• Transportation investments
• Non-transportation capital investments
• State and regional policy
• Economic and demographic changes

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Potential Zoning Scenarios

• Modeling the effects of
• upzoning,
• downzoning,
• reconfiguring zone boundaries,
• new zoning categories,
• density regulations or use changes for specific
  districts
• Should have specific zoning changes in mind first
  

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Potential Transportation Investment Senarios

• Modeling the effects of hypothetical
  transportation investments like
• new roads / highways
• new interchanges, exits
• road widening
• bus line expansion
• carpooling programs

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Potnential Non-Transportation Capital Investment
Scenarios

• All capital investments not included under the
  transportation scenarios like
• Utilities water, sewer, power, telecomm
• Schools
• Public facilities (libraries, post offices,
  courthouses)
• Parks/Open Space
• Joint public/private developments
• Major public institutions

Image source Microsoft Virtual Earth
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Potential State and Regional Policy Scenarios

• Hypothetical state and county level policies, or
  changes to existing policies, that are expected
  to affect land use or transportation like
• Tax policies
• property tax, current use, gas tax, speculation
  tax, etc.
• State land use policies 
• growth centers, Act 250, urban service boundary,
  changes to current use development penalties,
  etc.
• Transportation policies
• tolls, congestion pricing, gas tax, etc.
• Environmental conservation policies
• farmland, wetlands and shoreline protection, etc
• Air quality attainment standards

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Economic and Demographic Change Scenarios

• Economic and demographic changes to the county to
  be prepared for
• Economic Examples
• loss or gain of a major employer, increases or
  decreases in business taxes, telecommuting,
  energy price spikes or shortages, new federal
  fuel economy or tailpipe emissions requirements,
  changes in prices of raw materials, changes
  to the economy due to global warming
• Demographic Examples
• regional baby boom, influx of residents from
  other states due to global warming, changes in
  household characteristics

Image source Microsoft Virtual Earth
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Methods for implementing scenarios with
difficulty level

• Changes to control totals
• Changes to base year dbase tables
• Change to spatial inputs (GIS editing)
• Adding/changing variables to UrbanSim
• Adding/changing variables to TransCAD
• Combination of above
• Programming new behaviors

? increased level of uncertainty due to lack
of prior trends or data to analyze or lack of
knowledge of behavioral responses
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Examples

• Zoning density or use changes
• Transportation digitizing new interchanges/exits
• Policy Growth Centers Legislation (if boundaries
  available)
• Employment loss or gain of a major employer
• Non-transportation joint public/private
  developments

? increased level of uncertainty due to lack
of prior trends or data to analyze or lack of
knowledge of behavioral responses
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Project Status
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• More Information www.uvm.edu/envnr/countymodel
• or Austin Troy atroy_at_uvm.edu
• Thanks to US DOT (current funder), RSG, US EPA
  (previous funder), CCRPC, CCMPO and Research
  Assistants (Brian Miles, Alexandra Reiss, Galen
  Wilkerson).