I've been replaying Fallout 3 and I keep seeing military checkpoints in game. There's a military truck and then a sign about radiation. They seem to be in a wide permiter around Vault 87. One that I can remember is near Smith Casey's garage with a Sentry bot and a tent. Did anyone remember any in game explanation? I know that at the Germantown jail the, presumably, National Guard set up aid stations, so maybe this was from the same postwar response? The only other thing I can figure is that the FEV experiments were already being run at Vault 87 before the war and started leaking radiation.