So when do you think they should have stopped?

This must be a MN thing... A few weeks ago I was merging onto the highway and a car went by at the top of the on ramp, with smoke barreling out of the rear. i noticed as cars got up next to him, they would slow down and try to get his attention. I finally got close enough to this guy and same thing. He was totally oblivious! We were doing 65 down the freeway. All of a sudden the tire finally came off the rim. It rolled past him and then slowed enough just to miss the back of his car and into the ditch. Now he is doing 65 and just on his rim. He was not slowing down one bit! Finally he exited the freeway about 2 miles later. I dont know how he could not feel it or hear it... Some people should not breed!