Somehow I find it hard to believe that this rig is truly stable and roadworthy. But then, this state doesn't have regular safety/road-fitness vehicle inspections, only emission standards tests. Of course if there were regular safety inspections I expect the owner would simply take the truck in without its outsized accessory.
Ironic side point—the state does insist on inspecting cars brought in from another state. So the ludicrous situation was that all those decades ago, when we'd been living in Pennsylvania for a while, where all cars and trucks had to be inspected every six months, we had to have our cars inspected by the state police to register them, even though cars in-state are never inspected. Bureaucracy reasons in strange ways.
When Interstate 84 was built it cut right through the center of town, elevated high above the city streets. There are lots of concrete walls and structures supporting the elevated highway, and they see lots of action from taggers.