I don't know about you, but this would slow me down! People slow down and try to 'straddle' the hole, then breath a sigh of relief they completely clear it!
Scroll down and look at all three pictures. And it is much cheaper than speed cameras
Very clever, especially if moved around each day.
When a man wantonly destroys one of the works of man we call him a vandal. When he destroys one of the works of god we call him a sportsman. ~Joseph Wood Krutch