Late Again

My son just left at 7:33 for a class that starts at 7:30. He remembered the class, mentioned it to me 20 minutes before its starting time, and I reminded him that he should be getting ready to go soon. It is a 7 minute drive for him to get to the building the class is in. Add another few minutes to put his things in place and be ready to begin. Cognitively, he is bright. We have talked about planning ahead to get places on time. We have discussed the scientific impossibility of leaving home at 7:30 and arriving at his class at 7:30, and he understands it. It is not just this particular class, but any appointment when he has to be somewhere that he leaves home at the time he should be arriving at his destination. It does not matter what time of day it is, he is always late. We have given watches, planners, verbal reminders, and timers. Not one of these things has been effective in getting him places on time. His father and I have tried not reminding and prompting, to see if our son will become more independent and step up to the challenge of getting someplace (anyplace!) on time. No go. Truly. Nothing seems to make any difference. We are hoping for some new ideas, since our son wants to get a part-time job, but we don't know where he could work that doesn't involve showing up at a specified time and being on time.