25 CFR 170.105 - When must State governments consult with Tribes?
As identified in 23 U.S.C. 134 and 135, States will develop their STIP in consultation with Tribes in the area where the project is located. This includes providing for a process that coordinates transportation planning efforts carried out by the State with similar efforts carried out by Tribes. Regulations governing STIPs can be found at 23 CFR part 450.