That 18 wheeler rear bumper is also called a "Mansfield Bar"- - - - - -Jayne Mansfield got almost decapitated by the back end of a trailer that had no rear bumper when her stage manager drove under it at high speed and the car didn't stop until it hit the rear axle of the trailer.
https://www.mentalfloss.com/article/28155/how-jayne-mansfield-changed-design-tractor-trailers
