The speed limit on I-820 in this area is 60 MPH and just prior to exiting at the Pipeline Road exit you pass a speed limit sign on the freeway that says 60 MPH. As you start exiting at Pipeline Road (you are still essentially on the freeway) the exit ramp speed limit instantly changes to 35 MPH, it is posted with a sign but there is no warning prior to reaching the sign that changes the speed limit from 60 to 35 MPH. The police sit just down the exit ramp where it merges with the frontage road and clock motorists as they come off of the freeway. I asked why the speed limit was so drastic and low and the officer said there was a driving school facility in the area.