Traffic Impact Analysis (TIA) and Forecasting Future Traffic Needs: Lessons from Selected North Carolina Case Studies

The focus of this paper is to conduct an evaluation of selected traffic impact analysis (TIA) case studies, review current practice, and recommend procedures that could be adapted to better forecast and plan future traffic needs. Lessons from the evaluations indicate that considering regional traffic growth rate, peak hour factor (PHF), heavy vehicle percentage, and other off-site developments would yield relatively better TIA forecasts. Incomplete development with vacant parcels was observed at several case sites, possibly due to the state of the economy. Therefore, conducting analysis assuming multiple “build out” years (say, three and five years based on the magnitude of the development) as complete build out years would help state and local transportation agencies plan and better allocate resources based on the need.