Presentation Transcript
Implementing the FHWA Quick Response Freight Model in the Twin Cities : Implementing the FHWA Quick Response Freight Model in the Twin Cities Steve Wilson and Jonathan Ehrlich
SRF Consulting Group, Inc.
Dan Beagan
Cambridge Systematics, Inc.
Presented to Tenth Transportation Research Board
Planning Applications Conference
Twin Cities Regional Freight Planning Model : Twin Cities Regional Freight Planning Model
Objectives
Approach/Methodology
Calibration Considerations
Applications
Objectives of the Project : Objectives of the Project Improve New Regional Travel Demand Models
Better Reflect Impact of Trucks on Traffic Flow
Lay Groundwork for Multimodal Freight Analysis and Modeling
Connect to Statewide Freight Plan
Approach : Approach Based on FHWA Quick Response Freight Manual (1996)
Make use of local data
Make use of limited resources
Zonal Data : Zonal Data Employment Categories:
Agriculture, Mining, Construction
Manufacturing, Transportation, Communication, Utilities, Wholesale Trade
Retail Trade
Office and Services
Zonal Data : Zonal Data Employment Data
Census vs. ES202
Freight Facility Inventory
Quality Control Issues
Network Data : Network Data Highways
Prohibitions
Grade
Vehicle Classification Counts
Navigable Waterways
Terminal Locations
Locks and Dams
Railways
At-Grade Crossings
Intermodal Terminals
Other Data : Other Data Freight Analysis Framework
National Freight Flow Database
Growth Rates for External Trips
External Origin-Destination Survey
Distribution of External Trips
Other Data : Other Data Light Commercial Vehicles
In the regional model (large portion of NHBW trips)
Difficult to quantify either in vehicle classification counts or in home-interview surveys
MnDOT Light Commercial Vehicle Study, 1999
Four Step Model: Trip Generation : Four Step Model: Trip Generation By Vehicle Classification from QRFM
Single Unit
Combination
‘Light Commercial’
Function of Employment Type
External Trips based on External Station Vehicle Classification
Special Generator Capability
Four Step Model: Trip Distribution : Four Step Model: Trip Distribution Default gravity model friction factor curves from QRFM
Modify trip table using matrix estimation
Adjusted default curves based on estimated matrix
Four Step Model: Time of Day : Four Step Model: Time of Day Matches 24 time periods from Regional Model
Constant factors for each time period for each vehicle classification
Based on 24-hour vehicle classification count data
Four Step Model: Assignment : Four Step Model: Assignment Regional Model Assignment
Equilibrium Assignment
24 Time Periods
Five Assignment Purposes
SOV, LCV, HOV, SU, CMB
Three Paths
SOV/LCV, HOV, Truck
Passenger Car Equivalency
Validation : Validation Highway Link Volumes
VMT
Calibration Considerations : Calibration Considerations Data Availability
Vehicle Classification
Internal Origin-Destination
Trip Length Distribution
External Station Data
Commodity Data
Concurrent Regional Model Calibration
Regional Scope
Applications : Applications Forecasting Truck Traffic
Pavement Design
Development Impacts
System Level Responses
Modal Shift Impacts
Value of Time/Benefit-Cost
Truck Impacts on Congestion
Grade Crossing Analysis
Recommendations for Further Improvement : Recommendations for Further Improvement
Commercial Vehicle Tracking Survey
National/Multi-State Commodity Flow Model
External Truck Intercept Survey
Vehicle Classification Data
Questions? : Questions?
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