UrbanSim Model UrbanSim Model and Data and Data

DevelopmentDevelopmentJohn BrittingJohn Britting

Wasatch Front Regional Wasatch Front Regional CouncilCouncil

BackgroundBackground

Local application under development for Local application under development for 7 years7 years

Lawsuit settlement agreement increased Lawsuit settlement agreement increased our focus with respect to applicationour focus with respect to application

Need to determine whether suitable for Need to determine whether suitable for use locally by January 2004; with peer use locally by January 2004; with peer reviewreview Learned a lotLearned a lot modeling system operationalmodeling system operational not suitable for use yetnot suitable for use yet

What we want from What we want from UrbanSimUrbanSim

Tool for scenario Tool for scenario comparisonscomparisons

Interrelationships Interrelationships between between infrastructure infrastructure policies & land-usepolicies & land-use Can (potentially) Can (potentially)

inform planning inform planning process w.r.t. process w.r.t. secondary/cumulatisecondary/cumulative impactsve impacts

Outcome of Peer ReviewOutcome of Peer Review Move ahead…Move ahead…

Should be useful in Should be useful in short-termshort-term

Refine to meet Refine to meet WFRC’s needsWFRC’s needs

Reasonable results Reasonable results for significant for significant policiespolicies

(Eventually) Superior (Eventually) Superior to current processto current process

Commitment to Commitment to better planningbetter planning

However…However… Add’l tuning is Add’l tuning is

required for required for immediate useimmediate use

Needs a more Needs a more timely and improved timely and improved datasetdataset

Difficult to interpret Difficult to interpret the impacts of less the impacts of less significant policiessignificant policies

Not ready for Not ready for corridor studiescorridor studies

WFRC Resolution on WFRC Resolution on UrbanSimUrbanSim

The Council finds that additional The Council finds that additional testing of UrbanSim is needed…, testing of UrbanSim is needed…, (including) research into model (including) research into model refinement, data, policy refinement, data, policy implications, estimation of implications, estimation of resources needed, and an outreach resources needed, and an outreach program to familiarize planning program to familiarize planning staffs in the region on the staffs in the region on the appropriate and useful applications appropriate and useful applications of UrbanSim… of UrbanSim…

Good NewsGood News

Reasonable Reasonable response to large-response to large-scale policy scale policy changeschanges

The model is The model is operationaloperational

Initial outreach Initial outreach efforts were usefulefforts were useful

Not Good NewsNot Good News

Little/no sensitivity to Little/no sensitivity to less significant less significant policiespolicies

Database needs to be Database needs to be improvedimproved

RandomnessRandomness 0% or 100% 0% or 100%

residential vacancy residential vacancy ratesrates

Price inflationPrice inflation Still discovering bugsStill discovering bugs

2030 Residential Vacancy Rate00.001 - 0.010.01 - 0.020.02 - 0.030.03 - 0.040.04 - 0.050.051 - 0.10.1 - 0.250.25 - 0.50.5 - 0.750.75 - 0.999VacantNo Dwelling Units

Technical Work PlanTechnical Work Plan Data DevelopmentData Development

Refine representation of land policies and Refine representation of land policies and existing land-useexisting land-use

Model DevelopmentModel Development Re-estimate and validate all modelsRe-estimate and validate all models Improve logicImprove logic

Application UtilitiesApplication Utilities Make implementation smoother and more Make implementation smoother and more

effective (and working correctly)effective (and working correctly) Overcome randomnessOvercome randomness Summarize and present key indicators quickly Summarize and present key indicators quickly

(utilize SQL and GIS effectively to save time)(utilize SQL and GIS effectively to save time)

Need for Data DevelopmentNeed for Data DevelopmentResidential Capacity

Non-Residential Capacity

Dark blue is NYC dense

Key Models in UrbanSimKey Models in UrbanSim

Land Price ModelLand Price Model Developer ModelsDeveloper Models Residential Location Choice ModelResidential Location Choice Model Employment Location Choice ModelsEmployment Location Choice Models

Land Price Model Land Price Model DevelopmentDevelopment

GoalsGoals Reasonable relationships that will hold Reasonable relationships that will hold

over timeover time Thorough validation effortThorough validation effort Account for variation in value by type of Account for variation in value by type of

useuse Redevelopment analysisRedevelopment analysis

Appropriate sensitivity to transportation Appropriate sensitivity to transportation accessibilityaccessibility

Transportation/Land-use interactionTransportation/Land-use interaction

Preliminary ResultsPreliminary Results

Distance from highwayDistance from highway Residential/commercial (+, then -); Industrial (-)Residential/commercial (+, then -); Industrial (-)

Land price of neighborhood (+)Land price of neighborhood (+) Access. to employment (Residential +)Access. to employment (Residential +) Access. to population (Non-residential +)Access. to population (Non-residential +) Consistency between Zoning/Use (+)Consistency between Zoning/Use (+) Environmental factors (slope, open, roads, Environmental factors (slope, open, roads,

etc.)etc.) Residential (+, then -); Non-residential (-)Residential (+, then -); Non-residential (-)

Defining AccessibilityDefining Accessibility

Regional measure was initially used Regional measure was initially used – function of logsum and activity at – function of logsum and activity at destinationdestination

Local measure was also used in Local measure was also used in location choice models (walking location choice models (walking distance)distance)

We have three urban areasWe have three urban areas Regional, sub-regional and local Regional, sub-regional and local

accessibility likely to be importantaccessibility likely to be important

Regional Regional vs. vs.

Sub-Sub-regional regional AccessAccess• Regional on

left

• Both measures have merit

•Sub-regional shows logical patterns around 3 big urban cores

Land Land Price Price Model Model ValidatioValidationn Initial review Initial review

suggests suggests patterns are patterns are similarsimilar

More to do to More to do to validatevalidate

Categorical Categorical in applicationin application

Dealing with InflationDealing with Inflation

Average land price increases Average land price increases substantially over 33 year simulation (4% substantially over 33 year simulation (4% per year)per year) Accessibility/pop/emp are the culpritsAccessibility/pop/emp are the culprits

Average income stays in year 2000 Average income stays in year 2000 dollarsdollars

Options:Options: Use a different accessibility measureUse a different accessibility measure Inflate income or deflate priceInflate income or deflate price Use categorical price variablesUse categorical price variables

Additional Model Additional Model DevelopmentDevelopment

Need to use predicted land price in Need to use predicted land price in estimationestimation

Need to make implied behavior more Need to make implied behavior more consistent with theoretical understandingconsistent with theoretical understanding

Existing models:Existing models: (HH/Dev) higher price is always more attractive(HH/Dev) higher price is always more attractive (HH) closer proximity to highways is preferred(HH) closer proximity to highways is preferred Tricky to quantify residential character of Tricky to quantify residential character of

neighborhoodsneighborhoods A lot of multi-collinearity that clouds transparencyA lot of multi-collinearity that clouds transparency

Careful validation is necessaryCareful validation is necessary

Residential LocationResidential Location

Segmented by income quartileSegmented by income quartile Logical sensitivities to price by Logical sensitivities to price by

income segments (non-linear)income segments (non-linear) Larger households prefer lower Larger households prefer lower

density; smaller households prefer density; smaller households prefer higher density (non-linear)higher density (non-linear)

All income groups tend to clusterAll income groups tend to cluster Wrestling with accessibility measuresWrestling with accessibility measures

Model Development Model Development ChallengesChallenges

Not a lot of experience in practice Not a lot of experience in practice with these modelswith these models

Many non-linear relationships (e.g. Many non-linear relationships (e.g. price, density, accessibility)price, density, accessibility)

0-car vs. 1-car vs. 2-car accessibility 0-car vs. 1-car vs. 2-car accessibility parameters – what is a reasonable parameters – what is a reasonable relationship?relationship?

Behavior vs. Patterns in data Behavior vs. Patterns in data KISSKISS

Sensitivity to Sensitivity to AccessibilityAccessibility

How much is appropriate?How much is appropriate? Use sensitivity testing to understand Use sensitivity testing to understand

model response (Right direction? How model response (Right direction? How much change is needed to get a much change is needed to get a response?)response?)

Quantify average contribution to choice Quantify average contribution to choice probabilities & priceprobabilities & price

Utilize year-built data and TDM to do Utilize year-built data and TDM to do historical validation (quantify changes in historical validation (quantify changes in accessibility and development from 1992-accessibility and development from 1992-2002)2002)

RandomnessRandomnessRandom Variation in Residential Units by Geographic Level

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

cv_dur_1998 cv_dur_2000 cv_dur_2003 cv_dur_2008 cv_dur_2012 cv_dur_2016 cv_dur_2020 cv_dur_2025 cv_dur_2030

Year

Ave

rag

e C

oef

fici

ent

of

Var

iati

on

Gridcells

TAZs

Small Districts

Medium Districts

Large Districts

County

Region

Schedule/MilestonesSchedule/Milestones

LRP is due in 28 monthsLRP is due in 28 months Expect the work-plan coming out of the Expect the work-plan coming out of the

peer review to be complete in 1 yearpeer review to be complete in 1 year Experimentation is on-goingExperimentation is on-going Land-use plan refinements will be Land-use plan refinements will be

completed within 2 monthscompleted within 2 months Land price and residential location Land price and residential location

models will be completed within 1 models will be completed within 1 monthmonth