I just did a quick and dirty search of the Texas Transportation Code - you probably need to look more thoroughly but here is what jumped out at me initially:
§ 547.305. Restrictions on Use of Lights
(a) A motor vehicle lamp or illuminating device, other than a headlamp, spotlamp, auxiliary lamp, turn signal lamp, or emergency vehicle or school bus warning lamp, that projects a beam with an intensity brighter than 300 candlepower shall be directed so that no part of the high-intensity portion of the beam strikes the roadway at a distance of more than 75 feet from the vehicle.
(b) Except as expressly authorized by law, a person may not operate or move equipment or a vehicle, other than a police vehicle, with a lamp or device that displays a red light visible from directly in front of the center of the equipment or vehicle.
(c) A person may not operate a motor vehicle equipped with a red, white, or blue beacon, flashing, or alternating light unless the equipment is:
(1) used as specifically authorized by this chapter; or
(2) a running lamp, headlamp, taillamp, backup lamp, or turn signal lamp that is used as authorized by law.
(d) A vehicle may be equipped with alternately flashing lighting equipment described by Section 547.701 or 547.702 only if the vehicle is:
(1) a school bus;
(2) an authorized emergency vehicle;
(3) a church bus that has the words "church bus" printed on the front and rear of the bus so as to be clearly discernable to other vehicle operators;
(4) a tow truck while under the direction of a law enforcement officer at the scene of an accident or while hooking up to a disabled vehicle on a roadway; or
(5) a tow truck with a mounted light bar which has turn signals and stop lamps in addition to those required by Sections 547.322, 547.323, and 547.324, Transportation Code.
(e) A person may not operate highway maintenance or service equipment, including snow-removal equipment, that is not equipped with lamps or that does not display lighted lamps as required by the standards and specifications adopted by the Texas Department of Transportation.
(f) In this section "tow truck" means a motor vehicle or mechanical device that is adapted or used to tow, winch, or move a disabled vehicle.