I flagged down a couple one time. I was walking out of work and get in my carand look over to see a trailer fly by at highway speeds with the curb side slide tipped out on the top all **** eyed. I stompped the gas pedal down and caught them a 1/2 mile up the road. I pointed back at the trailer and as soon as the driver was checking his mirrors he spotted it and pulled over right away. I stopped and helpped him push it back in. I had never seen one tip out on the top like that. They thanked me and we parted ways.