Even if simply passing a law in Maryland wouldn’t solve the problem, it would have two benefits. First, there’s a normative effect to such a statute. We all knew from the dawn of texting that it was probably unsafe to do while driving, but it took actually making it illegal to got a lot of people to stop doing it. The same is true of snow on cars. We know it’s dangerous, but many of us may need a little extra push to do something about it. Second, the more states enact laws like these, the more resources will be devoted to helping commercial truckers deal with the situation. Truck stops often don’t have equipment to clear snow and ice from the roofs of cars, but if more states enact such laws, they probably will.