Eastbound Rt 32 from Columbia after passing NSA HQ building; there is a left "NSA Employees only" exit that goes in to a roundabout. Trooper sits in roundabout and shoots you from behind as you pass, then scoots out on roundabout entrance to Rt 32 and you’ve been had. Wooded area in median prior to exit/roundabout prevents visual on trooper until it’s too late. A proper RADAR detector (Valentine One) will give ample warning from back-scatter from RADAR gun.