E20 Speed Camera?

Hello all

I drove my first time today in Tokyo, from Tokyo to Fuji area.

On the way out and way in of Tokyo on the E20 Expressway I noticed a speed camera where the limit of that bit of road is 50kmph.

As someone who started living in Tokyo from a country where respecting the speed limits is a must if you want to keep your driving license I was in stock when I saw everyone going above 50kmph on that speed camera.

My question is, was everyone unaware of the camera, or that thing is doing nothing?

I saw people going around 60mph and others even more.

What am I missing?

Thank for teaching me in advance