Tex. Transportation Code § 544.011: LANE USE SIGNS.

If, on a highway having more than one lane with vehicles traveling in the same direction, the Texas Department of Transportation or a local authority places a sign that directs slower traffic to travel in a lane other than the farthest left lane, the sign must read "left lane for passing only."

Added by Acts 1997, 75th Leg., ch. 628, Sec. 1, eff. Sept. 1, 1997. Amended by Acts 1999, 76th Leg., ch. 62, Sec. 17.08, eff. Sept. 1, 1999.