In January 2020, the Hampton Roads Transportation Planning Organization (HRTPO) officially updated its Travel Demand Model (TDM). The HRTPO TDM is a computer model of the transportation system in Hampton Roads and is used as an analytical tool to support the regional transportation planning process. It can be used to develop traffic forecasts, test alternative transportation scenarios, and evaluate transportation systems or policies. HRTPO staff use outputs from the TDM to help decision makers determine where it is most beneficial to make long term transportation investments to the Hampton Roads region. Updates to the HRTPO TDM include:
The HRTPO TDM study area was expanded to include the City of Franklin and Southampton County. The other localities represented in the model include: Chesapeake, Gloucester County, Hampton, Isle of Wight County, James City County, Newport News, Norfolk, Poquoson, Portsmouth, Suffolk, Virginia Beach, Williamsburg, and York County.
The HRTPO TDM summarizes demographic data into small geographic areas known as Transportation Analysis Zones (TAZs). The Hampton Roads region is made up of approximately 1,200 TAZs. As part of the model update, TAZ boundaries were updated to reflect current land uses and densities. Roadway and transit networks were also updated to reflect recent transportation improvements.
The HRTPO TDM includes a toll choice component that helps determine whether drivers will choose to use tolled facilities in their trips. This component relies on the value of time of drivers. As part of the model update, the calculation for a driver’s value of time now accounts for household income.
The updated HRTPO TDM has the ability to investigate potential impacts of connected and autonomous vehicles. Connected vehicles are vehicles that use technology to wirelessly communicate with the driver, other vehicles on the road, roadside infrastructure, or the internet. Autonomous vehicles, also known as automated vehicles or driverless vehicles, vary in the levels of human interaction needed in order for them to be driven (human interaction behind the wheel is not required if full automation is achieved). Both connected and autonomous vehicles could drastically change the future of transportation, potentially providing major safety and mobility benefits in traveling.
As part of the development of the 2045 Long-Range Transportation Plan (LRTP), the recently updated TDM was used to forecast anticipated congestion assuming a “No Build” scenario (in other words, looking at potential future congestion if no additional improvements are made by the planning horizon year of 2045). Forecasting this 2045 LRTP “No Build” scenario is important because it highlights transportation system deficiencies. The “No Build” scenario also provides a baseline to which the benefits of proposed transportation improvements may be compared.