WisDOT: Big bumps on Zoo Interchange ramp to be smoothed out soon WisDOT: Big bumps on Zoo Interchange ramp to be smoothed out soon Two significant bumps have been catching drivers a little off guard on a ramp in Milwaukee's Zoo Interchange. But there is a promise of a smoother ride. MILWAUKEE - Two significant bumps have been catching drivers a little off guard on a ramp in Milwaukee's Zoo Interchange. But there is a promise of a smoother ride. From high above, it is a challenge to see just how big the bumps are. But as you watch from the ground, you can see they have a bounce to them.