NCTCOG And“Next Generation” Modeling

Ken Cervenka, P.E., AICPNorth Central Texas Council Of Governments

For

AMPO Travel Modeling Work Group MeetingKansas City, Missouri

September 28, 2004

Agenda

Current Modeling Environment

Multi-Year Network Coding

Next Steps—Near Term

Next Steps—Taking The Plunge

4,536,010

6,671,351

4,848,237

5,650,339

7,952,0708,503,146

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

8,000,000

9,000,000

10,000,000

1995 2000 2005 2010 2015 2020 2025 2030 2035 2040

Previous Plan Demographics (Mobility 2025 Update) New Plan Demographics (Mobility 2025, 2004 Update)

(Previous Plan)

(New Plan)

Total Population Within The Dallas – Fort Worth Metropolitan Planning Area

Four-Step Modeling Process

TRIP GENERATION

TRIP DISTRIBUTION

MODE CHOICE

ROADWAY ASSIGNMENT

TRAVEL TIMECONVERGENC

E

TRANSIT ASSIGNMENT

NO

YES

ZONE LAYERDEMOGRAPHIC INFORMATION

ROADWAY NETWORK

TRANSIT NETWORK

LOOPROADWAY SKIMS

TRANSIT SKIMS

INPUT

PROCESS

DECISION

Trip Distribution

Gamma-Format Gravity Model (7 Purposes) Four HBW Groups (Income Quartiles) – AM Peak HNW (Non-Airport) – OffPeak NHB (Non-Airport) – OffPeak Trucks (Vehicles With Six Or More Tires) – OffPeak

Base Year Trip Table Factoring (6 Purposes) HNW And NHB Airport Trips Four External-Related Auto/Truck Trips

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)

What Happens Next For NCTCOG

Training NCTCOG Staff Dallas Area Rapid Transit (DART) Staff Other Agencies (Local/TxDOT) Certification Of Consultants??? Model Implementers, Model Users, And Application Champions

Model Documentation Include The “What” As Well As The “Why” How To Run The Model/How To Understand The Model

What Happens Next (Cont.)

Possible Model Updates (0 - 3 Years) More Output Report Summaries (Tables, Graphs, Maps) Tests Of “Generic” Transit Skim/Mode Choice Procedures LOGSUM Consistencies Destination Choice Instead Of Gravity Model Trip Distribution Expansion Of Modeled Area Updated Land Use Modeling Tools Additional Time Periods For Traffic Assignment

Coordination With TxDOT Statewide Analysis Model

Traffic Microsimulation For Subarea Operations Analysis

Transit Model Outputs:Supply-Side Calculations

Number Of Coded Transit Lines

Roadway Network Links (Or Miles) With Transit

Total Physical Stops And “Transit Line” Stops How Many Are Rail Stations How Many Are Transit Park-And-Ride Locations

AM Peak And Mid-Day OffPeak Vehicle Miles AndHours Of Travel

Population And Employment Within “Buffer” Areas

Transit Model Outputs:Demand-Side Calculations

Transit Boardings And Alightings By Mode, By Route, By Line, Or By Rail Station For Weekday, Or For Each Of Four Assignments

Average Transfer Rates Boardings, Riders, And Boardings Per Rider

Transit Passenger Miles And Hours

Rail Station Mode-Of-Access/Egress Summaries

Multi-Year Network Concept

One Link/Node Layer And One Transit Route Layer ForALL 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

2003 Digital Aerial Photos (Six Inch)

Example: Future-Year Interchange

Single-Point Intersection

Network Coding EnvironmentAgency's

ArcGIS LayerTransCAD Multi-

Year Network

Roadway/Transit Corridor Study

Agency's ArcGIS Layer

TransCAD Multi-Year Network Alternatives

Agency's ArcGIS Layer

TransCAD Multi-Year Network

Final Recommendations

UpdatesUpdates

Updates

Checks

Checks

Updates

Checks

(Do Once)(Frequently)

GIS Database IntegrationTransCAD Multi-

Year Network

ArcGIS TIP/AQ Database and

Layer

ArcGIS Multi-Year Integrated

Layer

Other Databases/LayersTraffic Counts (Access)ITS Data (SQL)Skycomp Data (Access)GPS-Based Travel TimesAccidentsAt-Grade RR CrossingsIntersection Details

Export

Web-BasedInteractiveDisplays

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’t

Ready 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 BuildsUpon Successes/Failures Of Previous Implementations

Provide Support For New Basic Research Discourage A Start-From-Scratch Mentality

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