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NCTCOG And “Next 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. Agenda. Current Modeling Environment. Next Steps—Near Term. Multi-Year Network Coding.
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NCTCOG And“Next 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
Agenda • Current Modeling Environment • Next Steps—Near Term • Multi-Year Network Coding • Next Steps—Taking The Plunge
Total Population Within The Dallas – Fort Worth Metropolitan Planning Area
Four-Step Modeling Process DEMOGRAPHIC INFORMATION ZONE LAYER TRIP GENERATION ROADWAY NETWORK ROADWAY SKIMS TRIP DISTRIBUTION TRANSIT NETWORK MODE CHOICE LOOP ROADWAY ASSIGNMENT TRANSIT SKIMS TRAVEL TIME CONVERGENCE INPUT NO PROCESS YES DECISION TRANSIT ASSIGNMENT
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
Traffic Assignment User Equilibrium Generalized Cost (Three 30-Iteration Assignments) A.M. Peak (6:30a – 8:59a: 2.5 hours) P.M. Peak (3:00p – 6:29p: 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 (Doesn’t See Any HOV) Trucks (Vehicles With 6 Or More Tires)
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
Example: Blue Street Links Are Extracted To Travel Model Links
Agency's "Master Roadway Layer" • Covers 16-County NCTCOG Area
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?
Taking The Plunge:Activity-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
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
If Current Activity-Based Model Formulations/Estimations Aren’tReady 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/Consultant 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
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
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”