A person driving a motor vehicle shall stop such vehicle when approaching, from any direction, any school bus which is stopped on any highway, private road or school driveway for the purpose of taking on or discharging children, elderly individuals, or individuals with mental or physical disabilities, and shall remain stopped until all the individuals are clear of the highway, private road or school driveway and the bus is put in motion; any individual violating the foregoing is guilty of reckless driving. The driver of a vehicle, however, need not stop when approaching a school bus if the school bus is stopped on the other roadway of a divided highway, on an access road, or on a driveway when the other roadway, access road, or driveway is separated from the roadway on which he is driving by a physical barrier or an unpaved area. The driver of a vehicle also need not stop when approaching a school bus which is loading or discharging passengers from or onto property immediately adjacent to a school if the driver is directed by a law-enforcement officer or other duly authorized uniformed school crossing guard to pass the school bus. This section shall apply to school buses which are equipped with warning devices prescribed in § 46.2-1090 and are painted yellow with the words “School Bus” in black letters at least eight inches high on the front and rear thereof. Only school buses which are painted yellow and equipped with the required lettering and warning devices shall be identified as school buses. The testimony of the school bus driver, the supervisor of school buses or a law-enforcement officer that the vehicle was yellow, conspicuously marked as a school bus, and equipped with warning devices as prescribed in § 46.2-1090 is prima facie evidence that the vehicle is a school bus. Evidence that the bus was stopped with at least one warning device prescribed in § 46.2-1090 activated shall be considered prima facie evidence that the bus was stopped for the purpose of taking on or discharging children, elderly individuals, or individuals with mental or physical disabilities.