The two US bases/camps are located near the industrial area of Qatar, and the roads around them have miles and miles of trucks. In the mornings, the right side is essentially a truck parking lot. I've no idea why they stop, but they do.
I was fortunate to be traveling with a very skilled driver - in addition to the thousands of trucks, there are roundabouts everywhere and they take both skill and guts to navigate. (Major Williams is a VERY good driver.)