ILUTE

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

ILUTE

Presentation Outline

1. Urban Form – Transportation Interactions2. Need for Integrated Urban Models3. Microsimulation4. The ILUTE Project5. Key Features of ILUTE6. Modelling Activity/Travel -- TASHA

ILUTE

Transportation and urban formare fundamentally linked. Howwe build our city directlydetermines travel needs, viabilityof alternative travel modes, etc.

Transportation, in turn, influencesland development and locationchoices of people & firms.

ILUTE

There are many major employmentareas in the GTA, but the Torontodowntown is by far the greatestdensity centre.

Employment distributions anddensities, in particular, haveenormous impacts on travelmode choice.

1996 Employment Levels, GTA

1996 Employment Densities, GTA

(Source: Haider, 2003)

(Source: Haider, 2003)

ILUTE

ILUTE

To understand these complex transportation – urban form interactionsand to analyse the wide variety of policies (transportation, housing,etc.) that affect the urban system requires integrated, comprehensivemodels of transportation and land use.

LandDevelopment

Location Choice

ActivitySchedules

Activity Patterns

TransportationNetwork

AutomobileOwnership

Travel Demand

Network Flows

URBAN ACTIVITY SYSTEM TRANSPORTATION SYSTEM

Demographics

RegionalEconomics

GovernmentPolicies

INPUTS

ILUTE

Example Application: The Toronto Waterfront

What would be the impact of tearing down theGardiner Expressway? What if it wasn’treplaced? What transit options might exist?What would be the impact on population &employment distributions? …

2005 evolve

2010 2030_B

2030_C

branchand

evolve

Base Year

Event Year

Target Year(Policy Option B)

Target Year(Policy Option C)

2030_A

Target Year(Policy Option A)

ILUTE

Example Application: Places to Grow

What will be the impact of a greenbelt on:• housing density & prices?• employment concentration?• transit viability?• congestion?• emissions?• …

ILUTE

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.

ILUTE

Microsimulation

“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”

t = t0

Synthesis of Base Sample

For t = t0

Endogenous Changes to

Sample during this t

DisaggregateBehavioral Model

Behavior/System Stateat (t + t)

Exogenous Inputsthis t

t = t + t

ILUTE

Why Microsimulate?

VKT

TimeBaseYear

ForecastHorizon

HistoricalTrend

TrendProjection

Dynamic, path-dependentresponse to policyinitiatives

Static equilibriumprojection

To explore alternative futures and “emergent behaviour”.

ILUTE

The ILUTE Modeling Project

In Canada, the PROCESSUS Network is working on microsimulation modelling within the Integrated Land Use, Transportation, Environment (ILUTE) Modelling Project.

Flows, Times, etc. External Impacts

Land Use

Location Choice

Auto Ownership

Activity/Travel &Goods Movement

Demographics

Regional Economics

Government Policies

Transport SystemDynamic Traffic

Assignment Model

ILUTE

Object-Oriented, Agent-Based Models

Person 1

Agenda Schedule

Person 1

Agenda Schedule

Household Dwelling Unit Zone

Worker Job Firm

Building

Agenda

Vehicle

AgendaSchedule

• 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

ILUTE

Markets: Agent Interactions

Scheduling/Planning: Agent Decision-Making

Temporal / Spatial(Physical World)Representation

ILUTE

The ILUTEPyramid

ILUTE

Microsimulating Markets

Many markets are of interest within ILUTE (housing, labour, commercial real estate, etc.). Market interaction is a three-stage process:

Become Activein the Market

ConstrainedSearch

Bidding &Search Termination

Active in Housing Market (Uninformed)

Inactive in Market

decide to become active

decide to remain inactiveInformed

get information

Assessing

decide to continue - get search results

decide to back out

ask for broader search

Successfully Transacted

decide to purchase

decide to back out

process implications

ILUTE

Household-Level ModelsHousehold-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

Household

Person 1 Person 2

Requests for resources,availability for tasks

Allocationof resources,assignment oftasks

Pers1 Pers 2 Car 1

Request forcar

Time

Allocation ofthe car to agiven person

ILUTE

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)

Software Status

• 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

ILUTE

Modelling Daily Activity & Travel

Many problems exist with conventional urban travel demandforecasting models that limit the ability of such models to dealeffectively 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 effortto develop “next generation” models that have a sounder behaviouralbase so as to improve their credibility and their policy sensitivity.

ILUTE

TASHA

One example of this work is TASHA (Travel/Activity Scheduler forHousehold Agents). A second prototype version of the modelis 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)

ILUTE

Project 1• episode 1.1• episode 1.2• ….

Project 2• episode 2.1• episode 2.2• ….

Project N• episode N.1• episode N.2• ….

Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7

……

Scheduling Episodes

Tour-Based Mode Choice

Chain c:1. Home-Work2. Work-Lunch3. Lunch-Meeting4. Meeting-Work5. Work-Home

m1m2

m3m4

m5

Non-drive option for Chain c

m1 = drive

Sub-Chain s:2. Work-Lunch3. Lunch-Meeting4. Meeting-Work

m2m3

m4

Non-drive for Sub-chain s

m2 = drivem3 = drivem4 = drive

Drive forSub-chain s

m5 = drive

Drive Option for Chain c

mN = mode chosen for trip N

ILUTE

TASHA Application: GTA Growth & Transportation

Impacts

In a “Business as Usual” scenario with respect toGTA growth and transit system investment, autousage is projected to grow faster than population;transit usage will grow at about half the rate ofpopulation.

% Change in Daily Trips, 1996-2031 by Mode

68.8 67.6

34.3

105.7

61.9 66.6

101.2

42.5

64.2

0.0

20.0

40.0

60.0

80.0

100.0

120.0

1

Drive

Pass

Transit

GO-Rail

Walk

Cycle

Sch-bus

Taxi

Total

% Change in Daily VKT & Emissions, 1996-2031

6875.0 78.3

65.0

95.2

75.1

0102030405060708090

100

1

VKT

CO2

CO

NOx

HC

Fuel

% Change in Population & Employment, 1996-2031

55.8

88.2

0.010.020.030.040.050.060.070.080.090.0

100.0

1

Population

Employment

Pop. Growth Rate

Pop. Growth Rate

ILUTE

Highway 401 &Allen Road InterchangeUofT Paramics simulation model

ILUTE Model Output

Thank you.