Except as otherwise provided in this section, each bus on a motor carrier's roster must display the motor carrier's legal name or assumed name as listed on its application for authority or official request for name change as submitted to the department on both sides of the bus in a color that is in sharp contrast to the background color and in a size that is visible from a distance of not less than 50 feet. The display required under this section must meet the vehicle identification requirements of 49 CFR parts 390 to 399.