Frequent speed enforcement on Rt. 123 bridge over Occoquan River. Police work both directions. Going south on 123, they hide to the right of the light at the end of bridge, or sometimes to the right at the beginning of the bridge. Perhaps a little more often, they are catching northbound drivers coming from Woodbridge over the bridge. They hide just past the curve at the end of the bridge. Going northbound out of Woodbridge, speed limit is 35 mph. Southbound speed limit switches from 55 mph to 35 mph just before the bridge. I usually see them late mornings and weekends.