The Bluesmobile was portrayed as being a surplus police car from my town. https://en.wikipedia.org/wiki/Bluesmobile I was in high school when the movie was being filmed, and I remember one day going to Victory auto wreckers in Bensenville, a suburb just south of O Hare airport, and the yard was full of stacks of wrecked police cars. When the movie came out, I figured out where they had come from! I wish I had a camera with me so I would have pictures of them there at the boneyard.