I've seen Mr. Miller present at Black Hat and have talked with him about my own vulnerability reports to automotive vendors (I worked with one about two years ago to fix a rather embarrassing remotely exploitable flaw). However, I do not support testing or demonstrating any of the flaws on open public roads. Unforeseen things can and do happen. If the reporter would have been rear-ended this wouldn't have gone well for either researcher & that's enough right there to justify not doing this on public roads. The term "keep it to the track" which is often applied to the automotive racing scene is more than applicable here. The general public already tends to have a negative view of security researchers and performing "research" like this just re-enforces the perception.
