Bob Dawg, a 17 lb. dog sits in one of those oblong plastic milk crates that I have bungy corded down to the passenger seat. I have carpet lining the bottom and a foam swim noddle cut to fit along the front edge with a piece on non skid tape attached to it. if he sits down he can see out but he usually rides standing up with his front feet on the swim noodle. 1500 miles and 0 problems except he doesn't want to ride in the truck anymore.