An Integrated Tour-based Truck Travel Forecasting Model Ian Harrington Central Transportation...
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Transcript of An Integrated Tour-based Truck Travel Forecasting Model Ian Harrington Central Transportation...
An Integrated Tour-basedTruck Travel Forecasting Model
Ian Harrington
Central Transportation Planning Staff
Boston, Massachusetts
Outline of Presentation
• Why prepare a new truck model?• Identifying available data• Trip generation model structure• Trip distribution model structure• Trip table adjustment• Forecasting future truck travel
Why Prepare a New Truck Model?
• Previous truck trip tables based on old survey data
• Using truck trip tables allows for no estimation of impact of changes in demographics, infrastructure, tolls, or other changes in regional transportation system
Data Available forTruck Travel Forecasts
• Truck ownership data• Truck/Vehicle Inventory and Use Surveys• Residential location and characteristics• Survey of sample of local businesses• Field observations of trucks• Truck trip generation rates• Interregional truck trip table• Vehicle classification counts
Trip Generation Model Structure
Trucks fall into the following use categories:• Tankers• Household Goods• Truckload/Less-than-Truckload• Food and Warehouse Distribution• Intermodal• Package• Heavy• Retail• Pickup/Van
Trip Generation Model Structure
Truck tours consist of the following trip types:• Regional Truck Tour Ends• Intermediate Starts and Stops• Regional Truck Entrances/Exits• External Truck Entrances/Exits• Through Truck Entrances/Exits
Regional Truck Tour EndsNumber of truck tour ends is a function of:• Number of trucks• Number of tours per day• Portion of days each truck active
TE = 2 * Trucks * Tours * % Days Active Day
Estimated for each truck use category
Regional Truck Tour Ends
Number of trucks per employee by industrial sector based on CTPS survey
AverageSector Trucks/EmpGovernment 0.060Manufacturing 0.045
Agric, Mining, & Constr 0.539Transport, Comm, & Util 0.262
Service 0.030Fin, Insur, & Real Estate 0.003
Retail 0.039Wholesale 0.147
0.076
Regional Truck Tour Ends
Cross-classification of trucks by use category and industry based on CTPS field observations
Hhld LTL & Food & PickupSector TankersGoods TruckloadWarehouseIntermodalPackage Heavy Retail and VanGovernment 0.0% 0.0% 0.0% 0.0% 0.0% 20.0% 48.0% 0.0% 32.0%Manufacturing 0.0% 0.0% 0.0% 42.2% 0.0% 0.0% 31.0% 1.7% 25.0%AMC 0.3% 0.0% 0.0% 0.3% 0.0% 0.0% 42.1% 0.3% 57.2%TCU 2.7% 13.2% 34.2% 1.5% 4.0% 11.9% 13.5% 0.2% 18.8%Service 0.7% 0.0% 0.0% 1.2% 0.0% 0.0% 27.6% 0.5% 69.8%FIRE 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 23.1% 0.0% 76.9%Retail 19.9% 0.0% 0.0% 11.2% 0.0% 0.0% 2.7% 53.4% 12.8%Wholesale 5.9% 0.0% 0.0% 78.6% 0.0% 0.0% 2.7% 5.9% 6.8%
Regional Truck Tour Ends
Trucks in Government and Manufacturing industries have distinct distributions by use category
Hhld LTL & Food &Sector TankersGoods TruckloadWarehouseIntermodalGovernment 0.0% 0.0% 0.0% 0.0% 0.0%Manufacturing 0.0% 0.0% 0.0% 42.2% 0.0%
PickupSector PackageHeavy Retail and VanGovernment 20.0% 48.0% 0.0% 32.0%Manufacturing 0.0% 31.0% 1.7% 25.0%
Regional Truck Tour EndsOperational data from TIUS/VIUS data for
MassachusettsDays Tours
Active per DayTankers 61.0% 2.01
Household Goods 63.8% 0.9LTL/TL 91.2% 0.9
Food/Warehouse 81.5% 1Intermodal 88.5% 0.95Package 81.5% 1.2Heavy 68.8% 1.15Retail 94.0% 1.1Pickup/Van 86.9% 1.3
Intermediate Starts and Stops
Based upon truck trip generation rates in literature with adjustments for Eastern MA
Hhld LTL Food & Inter- PU/Tankers Goods /TL Warehouse modal Package Heavy Retail Van Total
Government 0.0034 0.0004 0 0.05 0 0.04 0.02 0.015 0.09 0.219
Manufacturing 0.004 0.0003 0.05 0.09 0.003 0.05 0.06 0.021 0.15 0.428
Agric, Mining, & Constr 0.003 0.00005 0.05 0.05 0 0.03 0.03 0.02 0.1 0.283
Transport, Comm, & Util 0.0035 0.0003 0.05 0.05 0.001 0.044 0.044 0.01 0.05 0.253
Service 0.0017 0.0004 0 0.05 0 0.06 0.019 0.015 0.09 0.236
Fire, Insur, & Real Estate 0.003 0.0005 0 0.05 0 0.05 0.02 0.015 0.09 0.229
Retail 0.003 0.0002 0.01 0.53 0.0003 0.04 0.02 0.01 0.09 0.704
Wholesale 0.002 0.0001 0.05 0.06 0.0023 0.04 0.02 0.01 0.11 0.294
Households 0.0095 0.0009 0 0.002 0 0.03 0.035 0.015 0.121 0.213
Group Quarters 0.0010 0.0011 0 0.0008 0 0.0115 0.0035 0.0058 0.0465 0.070
Intermediate Starts and Stops
Truck trips generated per employee at government and manufacturing worksites
Hhld LTL Food & Inter-Tankers Goods /TL Warehousemodal
Government 0.0034 0.0004 0 0.05 0Manufacturing 0.004 0.0003 0.05 0.09 0.003
PU/Package Heavy Retail Van Total
Government 0.04 0.02 0.015 0.09 0.2188Manufacturing 0.05 0.06 0.021 0.15 0.4283
Intermediate Starts and Stops
Supply of intermediate starts and stops based on operational data:
S&S = Stops/Tour * Tour Ends/2
Stops Stopsper Tour per Tour
Tankers 7 Package 21Household Goods 2 Heavy 4LTL/Truckload 4 Retail 6Food & Warehouse 14 Business PU/Van 4Intermodal 2
Intermediate Starts and Stops
Intraregional truck tour starts and stops:
Intra S&S = Tour Ends/2 * (1 - % Tours Ext)
* Stops/Tour
Pct Trips Pct TripsExternal External
Tankers 24.0% Package 2.0%Household Goods 16.5% Heavy 11.0%LTL/Truckload 39.3% Retail 5.0%Food & Warehouse 8.5% Business PU/Van 18.0%Intermodal 50.0%
Intermediate Starts and Stops
Regional truck interregional tour
starts and stops:
Reg IX S&S = Tour Ends/2 * % Tours Ext
* Stops/Tour
Assume interregional tours have one-half the number of stops per tour within region
Intermediate Starts and Stops
External truck intermediate starts and stops:
Ext S&S = Total S&S – Intra S&S
– Local IX S&S
Regional Truck Entrances/Exits
Regional truck interregional tour external tour ends:
Reg IX Ext TE = 2 * Reg IX S&S Stops/Tour
Assume interregional tours have one half the number of stops per tour within region
External Truck Entrances/Exits
External truck tour ends
Ext TE = 2 * Ext S&S Stops/Tour
Assume interregional tours have one-half the number of stops per tour within region
Through Truck Entrances/Exits
Based on external survey truck volumes, subtract estimated crossings from total
Thru TE = Tot Vol – Reg IX Ext TE – Ext TE
Truck Trip Distribution
• Use estimated trip ends and adjust initial gamma functions to match estimated regional trip length frequencies by use category based on TIUS/VIUS data for Massachusetts and an interregional trip table
• Use double-TAZ setup to match appropriate trip end pairs in trip tables
Truck Trip Distribution
Match appropriate pairs of trip productions and attractions for intraregional and through truck trips
TAZ A Ext A TAZ B Extern BAttrs Attrs Attrs Attrs
TAZ A P:Local Reg TEsProds A:Local Reg S&Ss
Ext AProds
TAZ B P:Local Reg S&Ss P:Local Reg S&SsProds A:Local Reg TEs A:Local Reg S&Ss
Ext B P:Thru TEsProds A:Thru TEs
Truck Trip Distribution
Match appropriate pairs of trip productions and attractions for interregional truck trips
TAZ A Ext A TAZ B Extern BAttrs Attrs Attrs Attrs
TAZ A P:Reg IX S&Ss P:Reg IX S&SsProds A:Reg IX Ext S&Ss A:Reg IX Ext TEs
Ext A P:Reg IX Ext TEs
Prods A:Reg IX S&Ss
TAZ B P:Ext S&Ss P:Ext S&SsProds A:Ext S&Ss A:Ext TEs
Ext B P:Ext TEsProds A:Ext S&Ss
Trip Table Estimation
• Since estimated truck trip tables are based on so many assumptions, need to check distribution results
• Create set of truck vehicle counts by use category using vehicle classification counts and a cross-classification of truck use category and FHWA truck class
• Use resultant trip table as seed for new gamma functionsThree Five Six Seven Eight Nine Ten Eleven Totals
Tankers 757 2,499 587 12 336 800 43 0 5,033 2.2%Household Goods 1,722 532 12 0 67 136 0 0 2,470 1.1%LTL/Truckload 60 943 185 0 1,027 1,066 64 58 3,404 1.5%
Food & Warehouse 7,956 5,056 834 0 865 1,242 12 12 15,978 7.1%Intermodal 0 0 0 0 386 326 0 0 711 0.3%Package 9,032 3,681 125 0 0 0 0 0 12,837 5.7%Heavy 7,403 19,215 4,744 850 1,107 2,342 423 0 36,085 16.1%Retail 19,970 1,636 12 0 48 106 0 0 21,772 9.7%Business PU/Van 125,174 1,348 0 0 0 0 0 0 126,521 56.3%TOTALS 172,073 34,910 6,498 862 3,836 6,019 543 70 224,812
Forecasting Future Truck Travel
• Apply truck trip generation model -- with future scenario employment, household, group quarters, and external station trip ends -- to estimate tour ends, starts and stops, and entrances/exits
• Apply gamma functions and productions and attractions for initial estimate of truck trip tables
• Apply trip table adjustment factors to produce future-year truck trip tables based upon future-year demographics and network characteristics
Summary
• Now our truck travel forecasting model is sensitive to changes in regional demographic characteristics, infrastructure, tolls, and the regional transportation system.
Contact Information
Chief Transportation Planner
David S. [email protected]
Central Transportation Planning Staff to the Boston Region Metropolitan Planning Organization (www.bostonmpo.org)