1. Simulating Cities: An Overview of the ILUTE Approach
E.J. Miller
Dept. of Civil Engineering
University of Toronto
PROCESSUS Second International Colloquium
Toronto, June 13, 2005

2. Presentation Outline Urban Form – Transportation Interactions
Need for Integrated Urban Models
Microsimulation
The ILUTE Project
Key Features of ILUTE
Modelling Activity/Travel -- TASHA

3. Transportation and urban form
are fundamentally linked. How
we build our city directly
determines travel needs, viability
of alternative travel modes, etc.
Transportation, in turn, influences
land development and location
choices of people & firms.

4. Employment distributions and densities, in particular, have
enormous impacts on travel
mode choice.
1996 Employment Levels, GTA
(Source: Haider, 2003)
There are many major employment
areas in the GTA, but the Toronto
downtown is by far the greatest
density centre.
1996 Employment Densities, GTA
(Source: Haider, 2003)

6. TRANSPORTATION SYSTEM
To understand these complex transportation – urban form interactions
and to analyse the wide variety of policies (transportation, housing,
etc.) that affect the urban system requires integrated, comprehensive
models of transportation and land use.
INPUTS
URBAN ACTIVITY SYSTEM
TRANSPORTATION SYSTEM
Land
Development
Transportation
Network
Demographics
Location Choice
Automobile
Ownership
Regional
Economics
Travel Demand
Network Flows
Government
Policies
Activity
Schedules
Activity Patterns

7. Example Application: The Toronto Waterfront
What would be the impact of tearing down the
Gardiner Expressway? What if it wasn’t
replaced? What transit options might exist?
What would be the impact on population &
employment distributions? …
2030_A
Target Year
(Policy Option A)
2005
evolve
Base Year
branch and
evolve
2010
2030_B
Event Year
Target Year
(Policy Option B)
2030_C
Target Year
(Policy Option C)

8. Example Application: Places to Grow
What will be the impact of a greenbelt on:
housing density & prices?
employment concentration?
transit viability?
congestion?
emissions? …

9. Simulation Applications
Given the size and complexity of urban systems, a primary tool in the analysis of these systems is simulation, typically at the micro level of individual vehicles, trip-makers, households, etc.
The PROCESSUS Network is actively developing and applying microsimulation models of transportation networks and urban systems.

10. Microsimulation “Micro” implies a highly disaggregated model:
t = t0
“Micro” implies a highly disaggregated model:
spatially
socio-economically
(representation of actors)
representation of processes
“Simulation” implies:
numerical
dynamic (time dimension
explicit)
stochastic
end state is “evolved” rather than
“solved for”
Synthesis of Base Sample
For t = t0
Endogenous Changes to
Sample during this Dt
Exogenous Inputs
this Dt
t = t + Dt
Disaggregate
Behavioral Model
Behavior/System State
at (t + Dt)

11. Why Microsimulate?
To explore alternative futures and “emergent behaviour”.
Static equilibrium
projection
VKT
Trend
Projection
Dynamic, path-dependent
response to policy
initiatives
Historical
Trend
Time
Base
Year
Forecast
Horizon

12. The ILUTE Modeling Project
Demographics
Land Use
In Canada, the PROCESSUS Network is working on microsimulation modelling within the Integrated Land Use, Transportation, Environment (ILUTE) Modelling Project.
Regional Economics
Location Choice
Auto Ownership
Government Policies
Activity/Travel &
Goods Movement
Transport System
Dynamic Traffic
Assignment Model
Flows, Times, etc.
External Impacts

13. Object-Oriented, Agent-Based Models
The model is being developed within the OOP paradigm
OOP ideal for microsimulation applications
Model design focuses on definition of the objects which exist
& interact within the system
An intelligent object is an agent.
Agents:
perceive the world
around them
make autonomous
decisions
act into the world
Person 1
Agenda
Schedule
Household
Dwelling Unit
Zone
Worker
Job
Firm
Building
Vehicle

14. The ILUTE Pyramid ILUTE Temporal / Spatial (Physical World)
Markets: Agent Interactions
Scheduling/Planning: Agent Decision-Making
Temporal / Spatial
(Physical World)
Representation
ILUTE

15. Microsimulating Markets
Many markets are of interest within ILUTE (housing, labour, commercial real estate, etc.). Market interaction is a three-stage process:
Microsimulating Markets
Become Active
in the Market
Constrained
Search
Bidding &
Search Termination

16. Household-Level Models
Allocation
of resources,
assignment of
tasks
Household-level models are required to “properly” deal with many system components:
housing location/type choice
automobile ownership
demographics/household
structure/lifecycle stage
activity/travel scheduling
Households:
share resources among household
members
constrain member behavior
condition member decision-making
generate activities
Requests for resources,
availability for tasks
Person 1
Person 2
Pers1
Pers 2
Car 1
Time
Request for
car
Allocation of
the car to a
given person

17. Software Status
Development of the initial operational model is complete, documented as part of Ph.D. thesis, "ILUTE: An Operational Prototype of a Comprehensive Microsimulation Model Of Urban Systems" by Paul Salvini (2003)
Operational prototype running with
GTA 1996 base
Over 15,000 lines of C++ code in 60
classes
Fully documentation in UML
Runs on any Windows workstation
Ready for additional sub-models

18. Modelling Daily Activity & Travel
Many problems exist with conventional urban travel demand
forecasting models that limit the ability of such models to deal
effectively with modern, complex urban transportation systems,
especially the competition between auto and transit for travel markets.
The PROCESSUS Network is contributing to a world-wide effort
to develop “next generation” models that have a sounder behavioural
base so as to improve their credibility and their policy sensitivity.

19. TASHA One example of this work is TASHA (Travel/Activity Scheduler for
Household Agents). A second prototype version of the model
is expected to be operational by mid-summer. Key features include:
Activity-based
Household-based (only such model currently in existence)
Microsimulation-based
Agent-based, object-oriented
Capable of interfacing with either conventional aggregate
modelling systems or new disaggregate microsimulators at both
“input” and “output” ends of the model (unique to this model)

20. Scheduling Episodes Project 1 episode 1.1 episode 1.2 …. Project 2
Project N
episode N.1
episode N.2 …. ……
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7

21. Tour-Based Mode Choice
Chain c:
1. Home-Work
2. Work-Lunch
3. Lunch-Meeting
4. Meeting-Work
5. Work-Home
Tour-Based Mode Choice
Drive Option for Chain c
Non-drive option for Chain c
m1 = drive m5 m4 m3
Sub-Chain s:
2. Work-Lunch
3. Lunch-Meeting
4. Meeting-Work m2 m1
mN = mode chosen for trip N
Drive for
Sub-chain s
Non-drive for
Sub-chain s
m2 = drive
m3 = drive
m4 = drive m4 m3 m2
m5 = drive

22. TASHA Application: GTA Growth & Transportation Impacts
Pop. Growth Rate
Pop. Growth Rate
In a “Business as Usual” scenario with respect to
GTA growth and transit system investment, auto
usage is projected to grow faster than population;
transit usage will grow at about half the rate of
population.

23. Thank you. ILUTE Model Output Highway 401 & Allen Road Interchange
UofT Paramics simulation model
ILUTE Model Output