I've driven over a few of these in Switzerland the last couple (few?) years, none this length but they are used on the autoroute around the Lake Geneva area som

I've driven over a few of these in Switzerland the last couple (few?) years, none this length but they are used on the autoroute around the Lake Geneva area sometimes. The speed is dropped to 60km/h and enforced by way of speed cameras - I have seen plenty of cars being flashed in the approach to the ramps.