Where they are placed is often a result of either geography or history. Some of these things have been there for decades and decades. Certainly the level of attention we give them and the kinds of services and the kinds of enforcement capabilities that we would put in a location would certainly be a function of the enforcement profile there: the types of traffic that would go through, the hours they would go through, and the sorts of things that we've seen historically.
On November 1st, 2010. See this statement in context.