In florida, predominately along the west coast I75, there are a few truck weigh stops, as you are approaching there is a massive looking sonar/radar device hanging high over the right side lanes.
Also I have seen on the turnpike at least in broward county what appears to be a truck monitoring setup of some sort, there is a small overpass over the turnpike (southbound) and there is a row of many video/photo whatever angeled downward at the rear of passing traffic. Also under the over pass is a moblietrailer that has all the cables running towards it, been there for awhile. It not speed enforfement, trust me I know. Just wondering what equipment they are using and for what? Traffic monitoring or electronic truck weigh in while in motion???