Any dog driven around in the bed of a pickup truck lives life at the mercy of an idiot. Why would I say something so unkind? Because dog owners like that (they're not, by definition dog parents) consider themselves immune to accidents or so much as ever having to stomp on the brakes. This dog's owner is more in love with the image of a tough guy with a hunting dog in the back of his 150 than he is with his dog.
A dog has a high center of gravity to begin with. All it takes is the minimal sideways moment of an unanticipated swerve to launch them out of a truck, even without a full-blown accident. If there is an impact, the dog will enter free flight - which always ends with a hard landing. It's not the flying that hurts, it's the landing. I'm sure this particular gentleman would point out that his dog is attached to something by his collar. To which I reply that this represents the hope that the dog might die more quickly from being hanged than broken in half on a telephone pole.
Riding dogs in the beds of pickup trucks is about a half notch down from allowing people to carry loaded guns in bars.