NCTCOG And Next Generation Modeling

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NCTCOG AndNext Generation Modeling

• Ken Cervenka, P.E., AICP
• North Central Texas Council Of Governments
• For
• AMPO Travel Modeling Work Group Meeting
• Kansas City, Missouri
• September 28, 2004

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Agenda

• Current Modeling Environment

Next StepsNear Term
Multi-Year Network Coding
Next StepsTaking The Plunge
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Total Population Within The Dallas Fort Worth
Metropolitan Planning Area
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Four-Step Modeling Process
ZONE LAYER
DEMOGRAPHIC INFORMATION
TRIP GENERATION
ROADWAY NETWORK
TRIP DISTRIBUTION
ROADWAY SKIMS
MODE CHOICE
TRANSIT NETWORK
LOOP
ROADWAY ASSIGNMENT
TRANSIT SKIMS
TRAVEL TIME CONVERGENCE
INPUT
NO
PROCESS
YES
DECISION
TRANSIT ASSIGNMENT
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Market Segmentation

• To Account For Differences In Commuter Behavior
• Segmentation Basis (6 HBW And 6 HNW)
• Household Income (3)
• Low
• Medium
• High
• Vehicle Availability For A Household (2)
• Vehicles Less Than Persons
• Vehicles Greater Than Or Equal To Persons

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Traffic Assignment
User Equilibrium Generalized Cost (Three
30-Iteration Assignments) A.M. Peak (630a
859a 2.5 hours) P.M. Peak (300p 629p
3.5 hours) OffPeak (18 hours) Four Vehicle
Classes Loaded Simultaneously Drive Alone
(Sees HOV-Toll Lanes As Tolled) Shared-Ride
(Sees All HOV Lanes As Free) Shared-Ride
(Doesnt See Any HOV) Trucks (Vehicles With 6
Or More Tires)
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Multi-Year Network Concept

• One Link/Node Layer And One Transit Route Layer
  For
• ALL Years
• Contains ALL Streets
• Essentially A 25-Year TIP!
• Travel Model Network Extracted From All Streets
  Layer
• Link And Route Selections Based On Start And
  End
• Date Fields
• Local And Non-MPA Street Links Excluded

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Example Blue Street Links Are Extracted To
Travel Model Links
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Agency's "Master Roadway Layer"

• Covers 16-County NCTCOG Area

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2003 Digital Aerial Photos (Six Inch)

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Example Future-Year Interchange

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Single-Point Intersection

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Network Coding Environment
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GIS Database Integration
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Some Tough Issues

• True Multi-Year Coding Is A Complex Environment
• But Allows For Greater Consistency/Quality
  Control
• Between Travel Model Years (And With TIP)

Traffic Counts And Detailed Roadway
Data (Including Traffic/Transit Projections)
Should We Put Everything On the Web? Who Pays
For The Initial Collection Costs? Is
Everything Free To The End User? Should We Be
Concerned About Possible Misuse?
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Taking The PlungeActivity-Based (AB) Modeling

• Maybe It Is Put Up Or Shut Up Time!
• We Must Find Out Where Things Stand
• Rigorous Sensitivity Tests Of Estimated Models
• NCTCOG Can Test CEMDAP (UT-Austin/DFW Data)
• Other Agencies Can Test Other AB Model Brands

Major Issues For Resolution Current
Worthiness And Readiness Of AB Models
Spatial/Temporal Transferability Of
Formulations/Estimations If Not Ready
Realistic Costs And Timeframes For Improvements
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Simple Sensitivity Tests (Examples)

• Global Increase/Decrease Of Input Variables
• Area-Specific Increase/Decrease Of Input
  Variables
• Check Local/Regional Change In Travel Patterns
• Check Local/Regional Change In Person Miles
• Perform Same Tests With Implemented Four-Step
  Model

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If Current Activity-Based Model
Formulations/Estimations ArentReady For The
Real World

• Form An MPO (Or MPO/DOT) Consortium
• Pooled Funding/Staff Resources
• Pooled Survey Data And Network Skims
• Identify Realistic Project Scope
• Competitive Procurement Of University/Consultan
  t Team
• Independent Review Panel/Paid Workgroup Team
• Quarterly Meetings For Sponsors To Measure
  Progress
• Public Exposure May Help Keep Everyone
  Honest/Objective
• Must Deal With Proprietary Software Issues

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Desired Results ForPooled Funding Effort

• Applied Research Conducted In An Orderly Fashion
• Does A New Theory/Latest Fad Smell Right?

Each Model Calibration/Validation Effort
Builds Upon Successes/Failures Of Previous
Implementations
Provide Support For New Basic Research
Discourage A Start-From-Scratch Mentality
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For E-Copy Of This Presentation

• Type In This URL
• http//www.dfwinfo.com/trans/program_areas/travel_
  forecasting.html
• Or Simply Google On
• NCTCOG Travel Forecasting Program
• And Look Under Travel Forecasting Presentations