When I get off Route 3 North on Exit 2 at night, there is always at least one speed trap on the bridge. On the Nashua side, there is usually one or two (one facing each direction) on that patch of pavement between the roads, and on the Hudson side, the cops usually park in the grass alongside of the road, which makes them very hard to see until its too late. The limit there is 50MPH, and they will pull you over for doing 51 (Ive seen it happen more than once). I usually do about 40MPH, and they leave me alone.