Guidelines for NCDOT Project-Level Traffic Forecasting Procedures

This project documents a methodology and related procedures to accomplish project-level traffic forecasting for the North Carolina Department of Transportation. While the methodology is general and can guide an engineer or planner through various steps including field visits, local discussions, data collection, analysis and documentation, the procedures provide explicit analytical tools appropriate for the forecasting task. The methodology structures and systematizes the forecasting process using two general methods: (1) the hand method which utilizes spreadsheet procedures to address smaller, rather isolated projects, and (2) TransCAD which can evaluate larger projects that are part of complicated networks. Given Base Year traffic volumes, turning movements, land use and transportation network information, both methods provide estimates of future facility volumes and turning movements assuming alternative development scenarios. The methodology implicitly recognizes uncertainty in the forecasting process regarding development (trip generation) and the importance of truck traffic estimates for design.