When I went on as a single rider for Test Track in August 2005, it was joke. The Cast Member over heard me saying I was going to get a Fast Pass, then said I would walk right on as a single rider. So I took their advice & went in line, which was a mistake. The sigle rider line looked just as long as the stand by line which at the time was at 45 or 50 minutes. Because I did not want to have my Dad waiting forever for me thinking I would go right on the ride I got out of line, got a Fast Pass & when I went back to use it I walked right into the briefing room area where they show us what will happen on the ride, then waited about 5 minutes to get into the Test Track car.
Maybe someone else had a different experience then me, but just sharing my views on how things went for me.