Car queues

Coming through customs in my car I was left wondering how much fuel was eaten up in long queues of cars waiting their turn, each having to move 3 metres forward every 2-5 minutes.  Multiply that by every vehicle entry into the UK over the year, each cold-started on a ferry, and the emissions could be interesting to think about doing something about.  Queuing systems, mobile staff, ramps and tracks all come to mind.  Might even have some application at drive-in MacDonalds.