(a) A vehicle required to have brakes by this subchapter, other than special mobile equipment, shall be equipped with service brakes that:
(1) comply with the performance requirements of this subchapter; and
(2) are adequate to control the movement of the vehicle, including stopping and holding, under all loading conditions and when on any grade on which the vehicle is operated.
(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.