There is an airport bus (Germany) which has it's rear wheels covered by the fender. Even front wheels have strange shape of fender around them (tilted toward front). What purpose of that?
They may do it for the safety of passengers.
Passengers in the tarmac usually have been exhausted and disoriented after a long flight and possible jet-lag. They have at times small children tagging along with both hands holding luggage and carry on.
They need to be shielded from any moving part, tires, cavities, as well as the obvious spraying of water by the wheel.
The front wheels are usually not in the path of foot traffic.
An airport bus is unlikely to "need" efficient high speed aerodynamics, but it does need to be highly visible.
In the still picture, note the lights which are evenly spaced along the length of the bus, and that one of them is in exactly the same position as the rear wheel. The front two lights seem to be mounted on the front fairing as well.
Accidents where a luggage cart driver tries to drive through the middle of a parked bus because he thought the lights at each end were two separate short vehicles are preventable!