Slow drivers

Is there some kind of unwritten rule that everybody has to drive 10 mph under the speed limit on every main road in this area?

I moved here in October and I have never been so annoyed to leave my house every time I have to go somewhere.

It's even worse when there are 2 lanes and everyone in the left lane is driving slow. If you're going to drive slow, at least get the heck out of the way.