Adopting Innovative MethodsFor Planning
Ken Cervenka, P.E., AICPNorth Central Texas Council Of Governments
For TRB Workshop 111:
Innovative Travel Models: Proof of ConceptWashington, D.C.January 9, 2005
Agenda
Background (About NCTCOG)
So What Holds People Back?
What I Wish Would Happen
Thoughts To Provoke Discussion
Current NCTCOG Modeling
TransCAD Platform
5,000 Square Miles / 4,874 Zones
Fully-Batched Graphical User InterfaceBut Humans Must Still Analyze/Interpret TheResults (And Make Final Decisions)
Four-Step Process
TRIP GENERATION
TRIP DISTRIBUTION
MODE CHOICE
ROADWAY ASSIGNMENT
TRAVEL TIMECONVERGENCE
TRANSIT ASSIGNMENT
NO
YES
ZONE LAYERDEMOGRAPHIC INFORMATION
ROADWAY NETWORK
TRANSIT NETWORK
LOO
P
ROADWAY SKIMS
TRANSIT SKIMS
INPUT
PROCESS
DECISION
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 Area
What Happens Next For NCTCOG
Applications TrainingStaff / Other AgenciesCertify Consultants?
Document The “Whys” Of Our Model Assumptions
More (And More) Output SummariesTables, Graphs, Maps
Integrated GIS Database EnvironmentMulti-Year Roadway/Transit Network Coding
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 Integration
TransCAD 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
What Happens Next (Cont.)
Destination Choice/Gravity Model Comparisons
Expanded Model Area (8,000+ Square Miles)
Update Or Replace Land Use Model (Metropilus)
Coordination With TxDOT Statewide Analysis Model
Sensitivity Tests Of Activity-Based Model (CEMDAP)UT-Austin, NCTCOG, TTI, Texas DOT
So What Holds People Back?(Impediments To Progress)
Unclear How Much Current Tools May Be Causing Bad Decisions About New/Expanded Roadways And Transit Service
Also Unclear How Advanced Models Would Have Responded
Do We Trust Researchers/Developers Who Tell Us TheyHave Much Better Tools Ready For Our Investment
The Real Cost, Timeframe, Ease Of Use, etc.
Pressure For Speed In Model Runs, Ease Of Use, And (Sometimes) Ease Of Interpretation
Impediments To Progress (Cont.)
How Much Will It Cost?
How Long Will It Take To Get The Product?
How Long Will It Take To Run The Product?
How Useful Will Be The Model Results?Will They Make Sense To The Decision Makers?Is There Something Else I Should Have Done?
Impediments To Progress (Cont.)
Staff Limitations (Consultants)How Many In The Available Contractor Pool Know How To
Implement Anything Other Than Four-Step Models?
Staff Limitations (MPO/DOTs)Lower Public Agency Salaries Often Result In Progressive
Thinkers/Champions Switching To Consultant JobsYes, The Money Is Higher Elsewhere—But A Potential Dead End
For Actual Advancement Of The Practice!
Quality Of Local Survey Data/Demographics/NetworksA Model Estimated/Calibrated From Garbage Is Still Garbage
What I Wish Would Happen
We Need Clear Information As To Where Things Stand With Advanced Model Readiness
Rigorous Peer-Reviewed Examination Of Implemented ModelsEven Estimated (Non-Calibrated) Models Can Be Sensitivity
Tested
Major Issues For ResolutionCheck For Spatial/Temporal TransferabilityNeed Realistic Costs/Timeframes For Improvements
Pooled Funding For Applied Research Leading ToImplementation
MPO (Or MPO/DOT) Consortium
Sensitivity Tests (Examples)
Think Of These As Attempts To De-Mystify ComplexModeling Assumptions
Area-Specific Increase/Decrease Of Input VariablesCheck Local/Regional Change In Travel PatternsCheck Local/Regional Change In Vehicle Miles And Hours Of
TravelCheck Local/Regional Change In Transit Passenger Miles And
Hours Of TravelPerform Same Tests With Four-Step Model
Universally-EstimatedAnd Locally Calibrated Model
Competitive Procurement Of Multi-Disciplinary TeamUniversities, Consultants, Software VendorsIndependent (And Paid) Expert Review PanelIdentify Realistic MilestonesQuarterly Meetings For Sponsors To See ProgressPublic Exposure To (Help) Keep Everyone Honest
Pooled Model Estimation Data SetsConsistent Survey Data, LOS (Skims), And Area Characteristics
(Context Variables)Across Several Regions AND Across Time Within Regions
Desired Results For PooledFunding Effort
Applied Research Conducted In An Orderly FashionBoth Minds And Funds Are Being PooledMay Have Many Market Segments And Complex Equations
That Could Be “Collapsed” For Some Implementations
Each Model Calibration/Validation Effort BuildsUpon Successes/Failures Of Previous Implementations
Provide Significant Support For New ResearchBut Discourage A Start-From-Scratch MentalityFull Documentation Of Results A Criteria For More Funding
Thoughts For Discussion:Discrete Choice Methods
How Variable Is Value Of Time (Time vs. Cost)?Work And Non-Work VariationsType Of Work (i.e., Flexibility In Arrival Time)Decision Stage (Home Location vs. Activity Location vs. Mode
Choice vs. Path Choice)
Does The Quality Of Time Vary?In-Vehicle vs. Transit Wait Time (Yes)Transit In-Vehicle vs. Auto In-Vehicle TimeReliability Of Transit Service And Auto Times
Thoughts For Discussion:Land Use Modeling
Comparisons Have Already Been Done, But:Should A Peer Review Group Define Tests, Review Results, And
Figure Out Where Things Stand?
Impacts Of Travel Accessibility Versus All ElseAre The Right Sensitivities In Place?
Could A “Universal Model” Be Developed?Across-Region And Across-Time DataUniversal Estimation / Local Calibration
Thoughts For Discussion:Activity-Based Modeling
What Can Be Learned From RigorousExamination Of Existing Implementations?
Portland MetroSan Francisco CountyNew York (NYMTC)Columbus (MORPC)Florida (AMOS)
Do We Know What Sensitivity Tests Are Needed?
Thoughts For Discussion:Dynamic Traffic Assignment
(And Traffic Simulation)
Why Do So Many Different Models Exist?A Flavor Of The Month Club?
Are These Intended For Both Short- And Long-Horizon Traffic Operations Analysis?
If Forecasted Demand Far Outstrips Supply, WillAssignment Results Be Useful?
High V/C Ratios In Current Assignments Can Serve As“Red Flags” For Detailed Analysis