I don't understand why you went back to using a scooter, if you were so clearly able to diagnose the dangers, and had one fairly severe injury. Why not switch to a commuter bike (the ~1 ft wheel foldable ones)?

Also, separate question, my understanding is that potholes are mainly formed by freeze/thaw cycles -- weather not typically found in SF. Have you lived in Chicago or NYC? Can you contrast the pothole density between those three cities?