Someone else posted this one a couple years ago, but I want to add that the level of enforcement has gone up _dramatically_ over the last year. I don’t drive the road every day, but I do drive it fairly frequently, and, in the last year and a half, I have seen at least one (frequently more) police cars waiting to nab you if you’re going more than 5 mph over the limit every single time I’ve been on the road. It seems to be at its worst between the Rappahanock river and where the road narrows from 4 to 2 lanes. The only good thing to say, I suppose, is that, thus far, I’ve not noted any unmarked cars.