Our Istobal Bay has yellow metal guides about 1.5" above the floor & 1.5" high for the length of the bay. Plus the entrance has 4' reflective road posts that flop down to help customers line up inside the guides. Even with that help we do have customers who stop on top of the guides and then wonder why the machine stops because of concern for hitting the car. When they blame the machine I check the video to confirm that they were the cause and usually give them a mulligan.