While growing up in Salina, Kansas in the early 1970s, my gleefully self-destructive friend Eric and his hoodlum friends entertained themselves by joyriding on the backs of huge trailer trucks that were driving down a local stretch of highway.
The trucks congregated at a greasy spoon on the edge of town as the gang of miscreants hovered patiently on top of some kind of pedestrian foot bridge or underpass which straddled the road. Any truck that left the diner would have to drive under that structure, giving the kids an easy opportunity to jump on top of the trailer as it slowly passed underneath them.
Once the truck started to accelerate, the kids had only a few moments to enjoy the rush of dust, exhaust, and bugs before they had to climb down from the top of the trailer to the rear bumber, lest they be decapitated at the next underpass. While this particular maneuver wasn't the most challenging part of the ride, it suddenly became life threatening once when a new initiate to the ritual froze up with fear after climbing only halfway down to the bumper, leaving the kids on the roof screaming at him to get out of the way. Fortunately, one of the less patient kids on the roof simply started climbing down the ladder anyway, pushing the newbie all the way down to the bumper by repeatedly stepping on the kid's head.
With all four delinquents safely on the bumper, they would enjoy a couple minutes of high speed fun before the truck inevitably slowed down for hairpin curves near the military base. The dirt on the edge of the road had been plowed up to be loose and soft (possibly to hinder a land invasion of the base), providing a safe to leap to from a decelerating truck without serious injury. If the gang didn't jump off there, they'd be forced to keep hanging on for dozens of miles before the driver would need to slow down again. Predictably, the new kid hesitated on this move as well, so he missed the softer dirt and hit the hard ground with a loud thud, rolling a couple of times before coming to a stop.
The gang went over to check on the guy and were relieved to find that the dumbass was still alive. He did badly sprain his ankle, though, so there was some lasting evidence of their exploits other than the dirt on their clothes and the bugs in their hair. As one of their brothers drove them all home, the group severely grilled the newbie on how he should lie to his parents about the cause of his injury. Did he mess this part up as well? Of course he did; he is a dumbass.
Instead of something like "I sprained it playing basketball" or "a drunken old lady tripped me" he totally spilled the beans, and his freaked-out parents called the cops on the other kids. Fortunately, Eric's mom couldn't believe that her son would do something as stupid as jumping onto and off of a moving truck, so she incredulously dismissed the police with a wave of her hand.