Scotland has a reasonable claim to have invented half of the modern road. John McAdam became a trustee of the Ayrshire Turnpike in 1783 and spent ten years trying to improve road-building. Although his method of layering stones and raising the road above the surroundings was a considerable improvement, it required an American inventor, Edgar Hooley, to add the layers of tar or bitumen that gave us our modern Tar Macadam or ‘tarmac’. Scotland's claim to have invented much to run on those roads is less impressive. At the start of the twentieth century the Argyll motor car, made in Alexandria, near Dumbarton, won a number of prestige races but never made the transition to mass production. Under government pressure, Midlands-based car manufacturer Rootes opened an assembly plant at Linwood (a village about 15 miles south of Glasgow) in 1963. The Hillman Imp's status as a Scottish car brought it some success north of the border but it fell far short of expected sales and there were extra costs in bringing components made in the Midlands north and sending assembled cars back south for finishing. The ex-shipyard workers had no experience of car manufacture but they did have a history of union militancy which caused an unprecedented number of strikes and stoppages. After changing ownership a number of times and limping through various schemes for state support, the plant was finally closed in 1981.