>There would be screaming here if people were given speeding tickets based on elapsed time cameras, without being pulled over by a human being.

The New Jersey Turnpike tried something like that many years ago. It wasn't a ticket, but you were handed a warning slip when you paid your toll when you got off. If you went from your point of entry where you received your toll stub to your exit point where you paid in less time than the miles between the point indicated, you got the "warning". They never did implement it with fines or anything. This was back in the '70's or '80's, I think.