Dealing with traffic volume growth

I’m doing a baseline and design assessment for a road, and i have traffic growth forecasts for the next 20 years (with and without the design) which i’d like to make use of. I’m thinking about taking the following approach:

  1. Calibrate the model using baseline coding and traffic and fatalities for 2016.
  2. Create a new baseline dataset using the same baseline coding but with 2026 traffic flows, and using the calibration factors from step 1.
  3. Create a new design datatset using the design coding, forecast traffic flows 2026, and using the calibration factors from step 1.

I can then compare the FSI for datasets between steps 2 and 3. I’m using the midpoint traffic volume forecast (ie year 10) since that is about the average of year 1 and year 10.

Does this sound about right?

Hi Greg:
How does one code intersection volumes for the forecast year? I see that you have used the same volumes in the without project and design scenarios in the BIIG1 roads. Perhaps it won’t matter much since these are rural roads and there won’t be much growth at these intersections - I am coding these for similar roads in Central Vietnam provinces and it would be helpful to know.

Best - Krishnan