Laurence BrownIndiana DOT

John OttensmannIndiana University-Purdue University Indianapolis

Jon FrickerPurdue University

Li JinKittelson & Associates, Orlando, FL

Indiana State Travel Demand Model (ISTDM)◦ Developed by Indiana Department of

Transportation LUCI and luci2 Urban Simulation Models for

central Indiana◦ Developed by Center for Urban Policy and the

Environment INTRLUDE (Integrated Transportation Land-

Use Demand Estimation) Model◦ luci2 INDOT Statewide Model◦ Integrated with ISTDM

4579 internal TAZs 141 external TAZs Same geographical

units used in luci2 INDOT Statewide Model◦ TAZs around urban

areas split to reflect sewer service availability and implement urban growth boundary option

Simulates new urban development for TAZs◦ Allocates population growth and residential

development◦ Allocates employment growth and related

employment-related development◦ Optionally forecasts growth in local-service

employment Integrated with travel demand model

◦ Uses travel times generated by travel demand model

◦ Outputs population and employment for travel demand model

LandSat imagery for 1985, 1993, 2000◦ Land cover

classification◦ Reclassification to

estimate residential and employment-related land use

Population and employment data from travel demand model

Models estimated using data by TAZ for 2000, change from 1995-2000◦ Probability of residential development◦ Density of residential development◦ Probability of employment-related development◦ Density of employment-related development◦ Change in local-service sector industry

employment

Works in 5-year simulation periods Simulation driven by exogenous forecast of

population growth for entire state

Uses employment forecast by TAZ from travel demand model forecast for 2030

Option to predict local-service employment change

Predictors of local-service employment change◦ Accessibility to population change◦ Change in urban land in TAZ in previous period

Predict employment density by TAZ Allocate new employment-related

development to accommodated predicted employment growth

For split TAZs, new development allocated to portion with highest predicted probability of employment-related development

Predict probability of conversion of nonurban land to residential use by TAZ◦ Aggregate logit model◦ Accessibility to employment change◦ Availability of sewer utility service

Predict population density by TAZ◦ Accessibility to employment◦ Availability of sewer utility service

Probabilities adjusted uniformly to accommodated specified population growth

Population growth Density of residential development Sewer expansion Agriculture land preservation Urban growth boundaries Increased dispersal of development Importance of accessibility to employment Employment changes in specific TAZs

Input: travel times from ISTDM Outputs: population and employment by

industry for ISTDM Interface

◦ Original model interactive, with options specified by user

◦ Final version run from command line Options specified in a scenario definition file Population and employment output to files for use by

travel demand model

ISTDM is implemented in TransCAD Integration of luci2 Model and travel

demand model accomplished using the TransCAD GIS Developer’s Kit (GISDK)◦ Provides user interface to specify options for

simulation, including options for the luci2 Model◦ Manages exchange of data between the ISTDM

and the luci2 Model◦ Runs the simulations in the ISTDM and the luci2

Model

Overall simulation◦ Target year

luci2 Model◦ Whether to predict local-service employment◦ Population growth rate◦ Other scenario options

ISTDM◦ Network for each simulation year

Begins with luci2 simulation of change from 2000 to 2005◦ Model uses 2000 travel times from ISTDM◦ Model outputs population and employment for

2005 ISTDM simulates travel in 2005

◦ Model uses output from luci2 and network specified for 2005

◦ Model outputs travel times (congested skim tree) for 2005

luci2 simulates change from 2005 to 2010 Process continues to target year

ISTDM INTRLUDE

Generally high correlation between INTRLUDE and ISTDM forecasts

INTRLUDE forecasts show more variation spatially than ISTDM forecasts◦ More areas of higher density around urban areas◦ Overall greater spread of population growth over

broader areas

0.00

5000.00

10000.00

15000.00

20000.00

25000.00

0 5000 10000 15000 20000 25000

INTRLUDE Population Density 2030

IST

DM

Po

pu

lati

on

D

en

sit

y 2

03

0

Correlation r = 0.97

0

5000000

10000000

15000000

20000000

25000000

30000000

35000000

40000000

RuralInterstates

Other RuralPrincipalArterials

Rural MinorArterials

Rural MajorCollectors

UrbanInterstates

OtherUrban

Freeways &Expwys

OtherUrban

PrincipalArterials

UrbanMinor

Arterials

VMT forecasts in 2030

VMT (ISTDM)

VMT(INTRLUDE)

0

250000

500000

750000

1000000

1250000

1500000

1750000

2000000

2250000

RuralInterstates

Other RuralPrincipalArterials

Rural MinorArterials

Rural MajorCollectors

UrbanInterstates

Other UrbanFreeways &

Expwys

Other UrbanPrincipalArterials

Urban MinorArterials

VHT forecasts in 2030

VHT(ISTDM)

VHT(INTRLUDE)

Comparison of ISTDM and INTRLUDE simulation results for planned improvements

Sensitivity of model forecasts to luci2 Model scenario options

Simulations with planned intermediate-year network improvements included in model

Use in early stages of project scoping to -◦ Compare multiple project scenarios◦ Consider land use consumption of projects

Large upgrades and new projects of specific interest –◦ Indianapolis outer loop expressway (CISTMS)◦ U.S. 31 upgrade to limited access◦ I-69 new terrain/upgrade◦ Illiana expressway

Effects of major employment changes not included in INDOT 2030 forecast

Effects of recent downward adjustment in population and employment forecasts