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