John Loudon McAdam (born
John Lowdon McAdam, 23 September 1756<ref name="OPR /> – 26 November 1836) was a
Scottish engineer and road-builder. He invented a new process, "
macadamisation", for building roads with a smooth hard surface, using controlled materials of mixed particle size and predetermined structure, that would be more durable and less muddy than
soil-based tracks.