(a) When any church bus stops and indicates by flasher lights that the bus is loading or unloading passengers, every operator of a motor vehicle or motorcycle approaching it from any direction shall bring the motor vehicle or motorcycle to a full stop and shall not start or attempt to pass in any direction until the bus has finished receiving or discharging its passengers.
(b) If the bus is operated on multiple lane highways divided by a parkway or dividing strip of twenty feet (20') or more in width and if the bus is on the opposite side of the parkway or dividing strip, then the driver of the approaching vehicle need not stop but shall proceed with due caution for the safety of the passengers of the bus.