Purcellville, Virginia Roadblocks

I checked registration but all they asked for was to see my license. There were 4 deputies handling the road (2 for each direction) another handful in the parking lot where several vehicles had been pulled over in gas station parking lot. Could find no sign of prior announcement. Been driving the road for years during rush hour and this was the first road block I’ve seen. Google earth – 39deg 15′ 22.09"N 77deg 45′ 38.95"W has a good image of site. It’s perfect based on what this site describes.