Well, if you look at this data, virtually all of the tickets are for leaving your car in a street sweeping zone at the wrong time. So they are functioning as adjuncts of the street sweeping regime. Then you should think about this history of street sweeping in San Francisco. I think you might find that it is the opposite of your preconception. The wealthiest neighborhoods got rid of street sweeping decades ago, specifically because they didn't want to have to move their cars so much.