Motor carriers shall require each driver to demonstrate that the driver is capable of safely operating each different type of vehicle or vehicle combination (i.e., vehicles with different controls, gauges, of different size, or requiring different driving skills) before driving such vehicle(s) on a highway unsupervised. The driver's capability to operate the vehicle shall include special equipment such as wheelchair lifts, ramps, or wheelchair tie downs. This Section shall not apply to a motor carrier who is the owner and sole driver of a vehicle or combination of vehicles.