The bus ploughed into the side of the bridge and broke through a large section, crashing all the way down to bottom of the structure, metres away from Park Station.
The nose of the vehicle was planted firmly into the ground and emergency officials were standing near the broken glass and cement around it.
A large section of the road surrounding the wreckage was cordoned off while the road leading to the accident was also closed off.
The accident scene was a hive of activity with several Johannesburg Metro Police (JMPD) officers, emergency services and Johannesburg Road Agency (JRA) officials at the scene.
Pedestrians attempted to cross the cordoned off line to get a closer view of the bus, but were quickly reprimanded by officers who warned them to back away.
ER24 spokesman Russel Meiring said there were no passengers in the bus and the driver escaped with a few minor injuries.