Pulling over to get out, stretch, and refresh both the body and mind is just good motoring practice. It prevents drowsiness and fatigue, both top contributors to collisions. But if you just pull over onto the side of the highway, you run the risk of getting totally destroyed by a runaway truck tire.
This, my friends, is the opposite of karmic justice. As the video voiceover notes, she suffered three broken bones in the incident.
But just as well, if it isn't an emergency, don't just stop randomly on the side of the road. At the very least, find a gas station or a parking lot or something. Because you'll get hit in the face with a truck tire.