Rig on a roll

摘要

THE monster 18-wheel trucks that hurtle along America's highways carry most of the nation's freight. There are reckoned to be some 1.3m of these "semi-trailers", as the combination of a tractor unit and trailer are known. Such vehicles are called articulated lorries in Britain, although they tend to be a bit puny compared with American rigs that can weigh 32,000kg (70,ooolbs) or more. Not surprisingly the big semi-trailers take skill to handle-and they consume a lot of diesel. But a new development could reduce fuel consump tion and give truckers one less thing to worry about when on the open road.