I thought I had seen everything until the day I was traveling through Charlotte on my way to Georgia for a vacation with my parents a few years ago... in the lane next to us there was a cop in his patrol car, decked out in full uniform, getting road head from (what we assumed was) his gf. My dad (one of the most religious people I know) almost crashed the minivan.
I get a little paranoid on really busy roads, especially since guys love to drive big ol' trucks around here. You never know who's peeking in. As for road sex, every guy I dated drove a stick-shift and figuring out the logistics on that one wasn't easy. Oops...