As part of its effort to create an improved regional transportation model for the Hampton Roads area, VDOT is enabling the regional model to estimate truck movements.

Regional models, like the one used in Hampton Roads, were invented at the beginning of the interstate era 50 years ago and have been used since then to forecast changes in travel which occur as a result of changes in population, land use, and infrastructure.  In Hampton Roads the regional model is used by VDOT, HRTPO, HRT, and private firms to determine future transportation needs, conformity with air quality requirements, and the impacts of proposed transportation projects.

Given that the current 2000 Hampton Roads model was calibrated using data over ten years old, VDOT is re-calibrating the model using data from the year 2009, the latest available.  The new 2009 model will be based on:

• the travel behavior of 3,000 local households surveyed by the federal 2009 National Household Travel Survey (NHTS) financed in part by VDOT
• truck and auto counts collected in hundreds of local locations by VDOT.

In addition, in order to make the model more useful for today’s transportation questions, VDOT is adding the following capabilities to the model:

• differentiation between trucks and autos (current model simply estimates vehicles)
• subdividing daily vehicle volumes into four time periods: morning peak, mid day, afternoon peak,and evening (current model simply estimates 24-hour volumes).

The truck component of the model will enable users to forecast future truck volumes.  The time-period components of the model will enable users to better forecast the usage of toll roads whose rates vary by time of day and the usage of HOV lanes which have usage rules which vary by time of day.

It is expected that the new Hampton Roads regional transportation model will be available for usage later this year.