Virginia Transportation Modeling Program
Frequently Asked Questions
What is Travel Demand Modeling?
Travel demand modeling is the art of predicting travel behavior and demand for a specific future time frame, based on a number of assumptions.
What Is the Role of a Travel Demand Forecasting Model?
A Travel Demand Forecast Model (TDFM) is a tool used to support the transportation planning process.
It can be used to:
- Develop traffic forecasts
- Test alternative transportation scenarios
- Evaluate transportation systems
It is also used to help determine compliance with air quality conformity standards.
How Do I Obtain a Travel Demand Model from VDOT?Please fill out the travel model request form (PDF, 233 KB) and return it to the Transportation and Mobility Planning Division of the Virginia Department of Transportation (VDOT).
How Do I Contact With Modeling Questions?Send an e-mail to VTM@vdot.virginia.gov.
How Do I Get on the Mailing List for VTM Connection?Send your request in an e-mail to VTM@vdot.virginia.gov.
What Regions in Virginia Have a TDFM?There are currently 14 urban regions in the state that have TDFMs. See the Virginia model regions page.
How Is It Determined When an Area Should Have a TDFM?
When an urban area reaches a population of greater than 50,000, a metropolitan planning organization (MPO) is designated for that area.
The MPO is a policy committee that oversees any planning activities for their region.
A TDFM is normally created for an MPO area as a tool to assist in the creation of the long-range transportation plan and an air quality conformity analysis.
Can I Use a TDFM to Conduct Individual Intersection Analysis?
Due to a travel demand model's regional scope and macro-level nature, it is not well suited for detailed intersection analysis.
Other "micro-level" modeling tools, such as highway capacity software, Synchro or VISSIM, would be better suited for this type of analysis.
Can Transit Ridership Be Represented in a TDFM?
In larger urban regions where transit ridership comprises a significant amount of commuter travel, a mode-choice model can be developed to help predict future transit usage.
The Washington, D.C., Hampton Roads, and Richmond/Tri-Cities models include mode choice.
Are HOV Lanes and Tolls Taken Into Account in a TDFM?Where necessary, sophisticated models contain HOV travel and the effects of tolls on travel behavior.
Can I Get Bicycle and Pedestrian Information from a TDFM?
Because of their aggregate nature and regional scope, travel demand models do not forecast bicycle or pedestrian trips.