22-wheeler
Noun: A blockage created by a “careful driver” attempting to pass a tractor-trailer; upon reaching the back of the trailer, the car slows to 1 mph faster than the truck and takes 3 or 4 miles to pass before resuming normal speed.
Shep really had to use the bathroom and almost didn’t make it to the rest stop in time because some grandpa created a 22-wheeler right in front of him.