I'm currently on a road trip to LA to see a show.
Trying to find parking in downtown LA is quite the challenge. And it's made much worse when I saw a sign saying "Warning: Do not back up - severe tire damage" as I attempted to worm my way out of a full parking lot. I looked down and saw a row of large tire spikes.
These spikes are installed at entrances and exits of all the public parking lots I've visited in downtown LA. Usually there's one at the entrance and another at the exit. They retract down into the ground, and are curved in a way so that cars driving in the "correct" direction would push them down harmlessly while a car diving in the "wrong" direction would have its tires impaled on the spikes.
Now I'm from Philadelphia. I've never seen such blatantly dangerous and harmful access control devices in downtown Philadelphia. Here it's either a powered lift/tilting gate or a speedbump-like device. The other type of parking lot access control device I've seen is a row of powered bollards I saw in London and Cambridge (Great Britain).
Why do many (if not all) parking lots in downtown LA use retractable tire spikes as access control devices? What would be the benefit of a impaling a car on the spikes, causing damage to pretty much all parties involved (the driver/car owner, the parking lot operator, and the people trying to enter/exit the lot)?