One thing that might help the wait would be to exclude patrons who are obviously not "household". The person in front of me had a pickup bed filled to overflowing with material including 6 computers, industrial batteries, and about a dozen 5 gallon paint cans. It looked to be the waste from a entire small apartment complex or office park. Since that sort of site generates (at least) a truck-bed's worth of material, perhaps that could be picked up at the site of generation, rather than going through the line with households who have much less stuff and can get in and out faster.
(Plus, none of that load was packed per the instructions of the web site, so the workers had to spend a lot of time digging around in the bed. Even so, at the end of the line when the electronics which had been buried by the paint cans were revealed, they still couldn't empty the truck.)