On US and state highways, destination signing for major border crossing cities should be placed at major intersecting highways in accordance with the

Texas Manual on Uniform Traffic Control Devices

(TMUTCD). On freeways and expressways, either advance guide and exit direction signs or supplemental signs may be used to sign major intersecting highway routes leading to border cities.

Where multiple routes to a destination exist in the same area, the best route for each direction of travel should be signed. Because routes to major border cities in Mexico may involve a combination of routes, additional destination signing may be appropriate. See Signing in Section 7 of this chapter.

Normally, signing for border cities in Mexico should not extend more than about 50 miles from the Texas-Mexico border.