Section 547.503 - Display of Hazard Lamps(a) The operator of a vehicle that is described by Subsection (b) and that is stopped on a roadway or shoulder shall immediately display vehicular hazard warning lamps that comply with Section 547.331, unless the vehicle: (1) is parked lawfully in an urban district;(2) is stopped lawfully to receive or discharge a passenger;(3) is stopped to avoid conflict with other traffic;(4) is stopped to comply with a direction of a police officer or an official traffic-control device; or(5) displays other warning devices as required by Sections 547.504-547.507.(b) This section applies to a truck, bus, truck-tractor, trailer, semitrailer, or pole trailer at least 80 inches wide or at least 30 feet long.Tex. Transp. Code § 547.503
Acts 1995, 74th Leg., ch. 165, Sec. 1, eff. Sept. 1, 1995.