I've seen this movie more than thirty times but didn't notice this until I was given a copy on video. Elwood decides to demonstrate the merits of the "new" Bluesmobile by jumping the drawbridge. In the very last frames before they actually hit the bridge you can see the brakes lock on the right rear wheel. Not what you'd want to do if you were trying to get maximum speed in order to fly a 5,000 pound Monaco across an open drawbridge.