Police normally sit in the parking lot at the bottom of the overpass (south side) using radar guns. The speed limit on highway 41 (also called north 3rd street) is 40 mph on the north side of the overpass, but at the overpass and on the south side it is 30 mph. It is very easy for people to miss the 30 mph speed limit sign posted right before the overpass and by the time you factor in the step grade coming down the overpass you can easily exceed 45 mph in the 30 mph zone.