Simulating Cities: An Overview of the ILUTE Approach
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Transcript of Simulating Cities: An Overview of the ILUTE Approach
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
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