There is a double dip by my Vegas house. If you go into the first one too
fast, the next one is deeper, and the following hump is higher. There were
serious gouges in the second where people's frames and oil pans had grooved
the concrete. We had two people crash there after launch, one taking out a
fire hydrant and block wall, the other taking out a street light. I heard
one hellacious bang one day, a car launching from one into the depths of the
other, then being thrown into the air on the subsequent hump. I looked over
the fence in time to see a police cruiser that was the offender. The bump
is one block from their station house, so figured he musta been new. He had
to have one helluva jolt there, and must have smacked his head on the car's
ceiling. A week later a second one did it again.

Steve