Christof has a couple of good posts about the history and future of HOV/HOT lanes. Good stuff in there, so check it out.
One of the themes in Christof’s second post is the effect of access to and from HOV/HOT lanes and the adjoining businesses. On a related note, Eye on Williamson notes this Statesman article about who will and will not be helped by the design of the new toll roads in the Austin area. If the stated goal is to maximize revenues for the toll roads, then expect to hear a lot more of this sort of thing.