No person shall drive a bus and a motor carrier shall not require or permit a person to drive a bus unless—
(a)All standees on the bus are rearward of the standee line or other means prescribed in § 393.90 of this subchapter;
(b)All aisle seats in the bus conform to the requirements of § 393.91 of this subchapter; and
(c)Baggage or freight on the bus is stowed and secured in a manner which assures—
(1)Unrestricted freedom of movement to the driver and his proper operation of the bus;
(2)Unobstructed access to all exits by any occupant of the bus; and
(3)Protection of occupants of the bus against injury resulting from the falling or displacement of articles transported in the bus.