Driverless capability convoy trains of up to ten lorries could be coming to our roads next year as first trials begin. The lead vehicle would be driven as normal with the tailing vehicles all linked in to each through wifi, then all actions and course changes would be passed on down the convoy chain. The other vehicles would have drivers, but would only be needed in emergency situations or complicated junctions and route changes. The idea is that the trailing drivers could rest and relax on the longer trunk roads, then be more alert and ready when the convoy positions change or the convoy splits.
You can find more details here at cars.uk.msn.com