I live in Texas and I would unironically feel safer driving the normal ~10-15mph above the speed limit that traffic is normally going than go exactly the speed limit, because I don't want everyone else flying around me recklessly because they all know that nobody goes exactly the legal limit here.
Yes! Speed difference is dangerous. So yes the difference in speed between vehicle and stationary objects it can hit (trees, poles, parker cars). On highways without a divider the danger is from incoming cars as that will double the impact speed. On highways with dividers having speed different from cars around you can be dangerous because it means either you are changing lanes to pass often else others are changing lanes often to get around you.
