I decided to ride to Great Clips to get my haircut ( trying to cut out the truck as much as i can ) 14mi, no biggie, on my way back. I come up to a light with a car stuck at it, with his flashers on. I go around him, hear a rock get pinched between my back tire and the road. It usually happen a lot so I didn't pat attention to it, then I heard the THWACK!!! Scared the bejeebers out of me. They didn't say anything and they turned right down the street. But I did keep looking back to see if they were there but I think I was just being paranoid. Did get me to pick up the pace though.