When the Post Office initially opened there were a number of accidents caused by vehicles rolling backwards into he car behind. The authorities then employed someone to ensure that no other vehicle proceeded onto the "slopes" until the car in front was onto the next level.
Neither was it appreciated that the roof on the final level is (or was at the time) lower than two preceeding levels. It will not (or certainly did not) accept a Land Cruiser with lights on the top. The first to discover this was a police Land Cruiser with lights atop who firmly wedged himself into the space.