Uh-oh! Car trap!!

I LOVE this sign. I pass it every day on the way to work and it always makes me smile.

I wonder what sort of trap they have laid for the cars....is it a net on the ground that springs into the air scooping up the car when it drives onto it? Or maybe a mousetrap-style trap with a spring that snaps down on the unsuspecting car? Or a big cage that falls on top of the car as it dares to drive through the no go area. :o)