Tex. Transportation Code § 547.502: VISIBLE WARNING DEVICES REQUIRED.

(a) Except as provided by Subsection (b), a person who operates, outside an urban district or on a divided highway, a truck, bus, or truck-tractor or a motor vehicle towing a house trailer shall carry in the vehicle:

(1) at daytime:

(A) at least two red flags at least 12 inches square; and

(B) standards to support the flags; and

(2) at nighttime:

(A) at least three flares and at least three red-burning fusees;

(B) at least three red electric lanterns; or

(C) at least three portable red emergency reflectors.

(b) A person who operates an explosive cargo vehicle at nighttime:

(1) shall carry in the vehicle three red electric lanterns or three portable red emergency reflectors; and

(2) may not carry in the vehicle a flare, fusee, or signal produced by flame.

(c) A flare, electric lantern, or portable reflector must be visible and distinguishable at a distance of at least 600 feet at night under normal atmospheric conditions.

(d) A portable reflector unit must be designed and constructed to reflect a red light clearly visible at all distances from 100 to 600 feet under normal atmospheric conditions at night when directly in front of lawful lower beams of headlamps.

(e) A flare, fusee, electric lantern, portable reflector, or warning flag must be a type approved by the department.

Acts 1995, 74th Leg., ch. 165, Sec. 1, eff. Sept. 1, 1995.