Two of my touch free autos still have the old metal treadles, and I'd say that 95% of the calls I get are from people that don't stop in the correct spot. I'm thinking of just replacing the treadle with two photoeyes, one on each wall that see each other .. when the beam is broken by the front of the car, the stop light comes on and wash begins. It seems simple enough to get the eyes that send the signal when the beam is broken -- although I don't think I'll be able to keep the backup feature. Do you guys see any other problems beside the occasional 'challenged' driver that may keep rolling even though the stop light and horn come on?