Here's the post by forum member RPB in the other thread:
Well, yes, that's the DPS CDL handbook, which paraphrases the actual laws for commercial vehicles, but that may only be for commercial vehicles. If you are looking for the actual laws regarding lighting/flags on projecting loads to the sides or rear for a non-commercial Pickup truck/passenger vehicle/van etc .... look at:
Texas Transportation Code, Chapter 547, Section 547.382http://www.statutes.legis.state.tx.us/D
Sec. 547.382. LIGHTING EQUIPMENT ON PROJECTING LOADS. (a) A vehicle transporting a load that extends to the rear at least four feet beyond the bed or body of the vehicle shall display on the extreme end of the load at the times specified in Section 547.302(a):
(1) two red lamps visible at a distance of at least 500 feet from the rear;
(2) two red reflectors that indicate the maximum width and are visible at nighttime at all distances from 100 to 600 feet from the rear when directly in front of lawful lower beams of headlamps; and
(3) two red lamps, one on each side, that indicate the maximum overhang and are visible at a distance of at least 500 feet from the side.
(b) At all other times, a vehicle transporting a load that extends beyond the vehicle's sides or more than four feet beyond the vehicle's rear shall display red flags that:
(1) are at least 12 inches square;
(2) mark the extremities of the load; and
(3) are placed where a lamp is required by this section.
Acts 1995, 74th Leg., ch. 165, Sec. 1, eff. Sept. 1, 1995.