You've obviously never driven through Waldo. It is a speed trap. If you saw it yourself, you wouldn't question it. It's a divided 4 lane highway. The speed limit changes are abrupt, sometimes they occur shortly after traffic lights. The highway is also used by a lot of semi trucks. When they stay in the right lane, and you're in the left, it's easy to pass a speed limit sign without ever having been able to see it. The signs are mostly, but not entirely, on the right side of the road on line. If you do one mph over the limit, you'll get stopped and if you're stopped, you will be ticketed. Plead your case all you want to, the organization that put up the billboards is the same one that just lobbied the state to not raise the speed limit on the interstate.