Texas Transportation Code - TRANSP § 547.403. Service Brakes Required

(a) A vehicle required to have brakes by this subchapter, other than special mobile equipment, shall be equipped with service brakes that:

(b) A vehicle required to have brakes by this subchapter shall be equipped so that one control device operates the service brakes.  This subsection does not prohibit an additional control device that may be used to operate brakes on a towed vehicle.  A vehicle that tows another vehicle as a commodity when at least one set of the towed vehicle's wheels is on the roadway is not required to comply with this requirement unless the brakes on the towing and towed vehicles are designed to be operated by a single control on the towing vehicle.