[masraum]

Sec. 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."

Sec. 545.057. PASSING TO THE RIGHT. (a) An operator may pass to the right of another vehicle only if conditions permit safely passing to the right and:

(1) the vehicle being passed is making or about to make a left turn; and

(2) the operator is:

(A) on a highway having unobstructed pavement not occupied by parked vehicles and sufficient width for two or more lines of moving vehicles in each direction; or

(B) on a one-way street or on a roadway having traffic restricted to one direction of movement and the roadway is free from obstructions and wide enough for two or more lines of moving vehicles.

(b) An operator may not pass to the right by leaving the main traveled portion of a roadway except as provided by Section 545.058.


Sec. 545.051. DRIVING ON RIGHT SIDE OF ROADWAY. (a) An operator on a roadway of sufficient width shall drive on the right half of the roadway, unless:

(1) the operator is passing another vehicle;

(2) an obstruction necessitates moving the vehicle left of the center of the roadway and the operator yields the right-of-way to a vehicle that:

(A) is moving in the proper direction on the unobstructed portion of the roadway; and

(B) is an immediate hazard;

(3) the operator is on a roadway divided into three marked lanes for traffic; or

(4) the operator is on a roadway restricted to one-way traffic.

(b) An operator of a vehicle on a roadway moving more slowly than the normal speed of other vehicles at the time and place under the existing conditions shall drive in the right-hand lane available for vehicles, or as close as practicable to the right-hand curb or edge of the roadway, unless the operator is:

(1) passing another vehicle; or

(2) preparing for a left turn at an intersection or into a private road or driveway.

(c) An operator on a roadway having four or more lanes for moving vehicles and providing for two-way movement of vehicles may not drive left of the center line of the roadway except:

(1) as authorized by an official traffic-control device designating a specified lane to the left side of the center of the roadway for use by a vehicle not otherwise permitted to use the lane;

(2) under the conditions described by Subsection (a)(2); or

(3) in crossing the center line to make a left turn into or out of an alley, private road, or driveway.

I guess based on the above, the "and" in between 1 and 2 of 545.057 means that you can only pass on the right if there is someone turning left from the left lane.

Looks to me like it is a law.