Traffic forecasting involves determining who will develop the traffic forecast, how the forecast will be developed (i.e., which forecasting methodology), and who will approve the traffic forecast. After determining who will develop and approve the forecasts, it is suggested that the choice is marked in the traffic forecasting section of the

Scoping Form

by checking TPP Led or District Led.

Depending on who is developing and approving the traffic forecast, selecting forecast methodology may be necessary. If the project lies within an MPO with a TDM, then the analyst can consider using the MPO’s TDM. If the project is outside the MPO boundaries with a TDM, the analyst can consider using TxDOT’s Statewide Analysis Model (SAM) outputs.

Other methods of traffic forecasting include historical trends and growth patterns. Typically, more than one method of traffic forecasting is used to cross-validate forecast results.

Document traffic forecasting assumptions on the

Scoping Form

and include information about which MPO’s TDM will be used, where historical volumes will be taken to obtain a historical growth rate, or what planned land uses were used to develop growth patterns for traffic forecasting.

For additional guidance on traffic volume and forecasting, refer to the TxDOT TPP Traffic Forecasting Analysis Standard Operating Procedures (SOP). Coordinate with the TxDOT project manager to gain access to the latest SOP. An internal link to the SOP is also found in

Appendix B, Section 4 – External References (Reference 1)

.