1. Developing External and Truck Trips for a Regional Travel Model
Matt Stratton
Transportation Modeler
Statewide Planning Session
May 15, 2017
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2. Purpose
Develop a process to extract trip tables from the Ohio Statewide Model (ODOT) for MPO models
MPO regions:
Cleveland
Columbus
Cincinnati
Dayton

3. Introduction: State of the Practice
Regional models often rely on simplified models of external and truck travel:
Driven by observed traffic counts and internal zone production/attraction models
Little known of external zones that produce/attract trips
Internal trip generation and distribution treated as closed system

4. Important Aspects of External Trips
External-Internal and External-External trips often not covered by Household surveys
External zone production/attraction factors hard to capture without overarching model
Internal-External work trip formation depends on Internal work opportunities compared to External zones

5. Important Aspects of External Trips
External-Internal workers take job opportunities from Internal- Internal workers
Leads to modeling error if not accounted for
External trips play larger role:
Near regional model boundaries
On major roadways
In smaller regions

6. Our Approach Larger Scale Model Core Regional Model Generalizable
External trips are derived from a larger “mega” model that plays a meta role with respect to the external-internal proportions. The external trips should be sensitive to local land use.
Larger Scale Model
The core internal model (ABM) has to be properly scaled to reflect the external trip shares predicted by the inter-regional mega-model.
Core Regional Model
Approach need not rely on statewide model and ABM to be applicable, but can be applied with a simple model for a “halo” area around a smaller region.
Generalizable
Too many words

7. Our Approach

8. Statewide / “Mega” Model
Truck & Commercial Vehicle Trips
Transfer of Statewide models to MPO geography:
DCOM – Disaggregate Commercial Model
Disaggregate tour-based microsimulation of local delivery and service truck trips
ACOM – Aggregate Commercial Model
Aggregate econometric model that converts commodity flows to truck trips
Represents inter-urban trips that are longer than 50 miles
Too many words

9. Statewide / “Mega” Model
Truck & Commercial Vehicle Trips
DCOM is separately applied to MPO TAZs, land use, and employment
Internal ACOM trips from Statewide model are disaggregated to MPO zones, and then scaled to the proper proportion relative to the locally applied DCOM
Too many words

10. Making External Trips Policy-Sensitive
If MPO inputs differ from Statewide model, the following redistribution procedure is applied:
Cordon station productions and attractions from the Statewide model
Internal productions and attractions calculated based on the MPO trip generation equations for estimating IE truck and auto trip ends
Auto trip distribution done via gravity model
Truck trip distribution done with Fratar
Too many words

11. Making External Trips Policy-Sensitive
Trip tables from the statewide model are blended with the gravity/fratar model output with internal-TAZ specific weight, 𝑤_𝑖𝑇𝐴𝑍, that is normalized between 0 and 1, where a value of 0 means there is no difference between the MPO land use data and the Statewide model and the Statewide trips are used as is, and a value of 1 means one of the sources is 0 and the other is not, so the gravity/fratar results are used.
Too many words. Add equations.

12. Core Regional Model Accounting for External Auto Trips in Core ABM
Trip Production Side:
Proportion of workers commuting from internal zones to outside MPO region extracted from Statewide model (see map on next slide)
The internal work arrangement model was set with a “work outside the region” alternative.
Probabilities for this alternative driven by zonal proportions of workers leaving the region.
IE commute flow matrix used to assign internal workers to external stations
Too many words

13. Core Regional Model

14. Core Regional Model Accounting for External Auto Trips in Core ABM
Trip Attraction Side:
External workers take internal jobs (see map on next slide)
These jobs unavailable for internal workers
Proportion of jobs taken by external workers in each zone is used to calculate the number of jobs available to internal workers in each zone
Size term for the usual work location model is scaled by the ratio of total regional jobs available to internal workers relative to total internal jobs
Too many words

15. Core Regional Model

16. Integration: Model Component Flow

17. Integration: Model Component Flow

18. Integration: Model Component Flow

19. Future Directions
This model integration was one-directional (Statewide to MPO). Two- way integration could be useful.
How should overlapping non-work trips be handled?
In absence of mega models, more regions should expand geographic halos to capture commute-sheds

20. Future Directions
Household Travel Surveys can be better structured to capture internal-external travel behavior.
GPS important on this point
Establishment surveys can help with external-internal travel market.
Big Data vendors can be useful for seed matrices of external-external travel.

21. Many Thanks To Ohio Department of Transportation
Rebekah Anderson, Greg Giaimo
OKI Regional Council of Governments
Andrew Rohne
Miami Valley Regional Planning Commission
Ana Ramirez, Ami Parikh
Mid-Ohio Regional Planning Commission
Zhuojun Jiang
Northeast Ohio Areawide Coordinating Agency
Ali Makarachi
WSP USA
Chrissy Bernardo, Gaurav Vyas, Ashish Kulshrestha, Peter Vovsha

22. Contacts Matt Stratton Chrissy Bernardo Transportation Modeler
Systems Analysis Group
Chrissy Bernardo