Marked and unmarked cars frequently sit behind a fence of a large abondoned industrial building monetering mostly north bound traffic. The car can only be seen from a certain angle for about 2 seconds about 300 yards before you reach it. I don’t know if they station the motorcycle units there or not. Plainfield cops are notorious for ticketing drivers for going 1mph over the limit(in one case I heard of a ticket issued for 0.1 mph over but I have doubts as to the credibility of the source). Best advice go 25mph (5 under the limit) until you can see inside the fence with your mirrors before speeding up to a reasonale speed if every thing checks out.