My biggest memory is not necessary dangerous all the time but only certain times. I was on a "Gold Coast" tour from Key West to Galveston. We were leaving Tyndall Air Force Base (southeast of Panama City, FL) right around 4:30pm on a Friday as everyone was getting off duty at the AFB.
As we crossed the bridge into the Panama City area, tons of cars driven by young 20s year olds looking for a good time on Friday Night were flying bumper to bumper across the bridge. No shoulder, everyone speeding while trying to pass each other. I was actually planning in my head what I would do if I got knock off the bridge and survived. I have 75k+ miles of touring over 45 years and it is easily in the top 3 scariest moments.
However, I have feeling that if we had crossed at say 1pm it would have been perfectly fine.
Another time (around 1987) I was riding into Boston southbound on US1 due to a traffic construction detour, again at rush hour. Absolute chaos but since I was only 23, I didn't really care and/or know the danger. In hindsight, I realize how lucky I was and I sure the drivers thought I was nuts.
So in summary, the first example was not necessarily a dangerous road per se but a dangerous time. The second example was stupidity on my part so I can't really say it was a dangerous road in that I probably should not have even been on it.
Interesting thread. Tailwinds, John