Classic example of this today. On the dual carriageway between Tredegar Park and Bassaleg, the left lane is closed right at the top by the Bassaleg roundabout, but everyone is queuing in the right lane for its entire length, that's about 600yds of one completely empty lane and the other with traffic tailing back and completely blocking up Tredegar Park roundabout, causing terrible queues leaving the M4 on both slip roads. All because people won't use both lanes and merge in turn at the end. It's just bloody idiotic.