It used to be you needed a special license to drive something that big. Why's that not a thing any more?
I've heard that people drive these behemoths for safety reasons. Which makes sense—when two vehicles collide, the bigger one's gonna win. An arms race, basically, except bigger trucks instead of bigger bombs. If that's the case, then only government regulations can put a stop to it; people serving their self-interest certainly aren't going to.