What is Macadam?
John Loudon McAdam (1756-1836)
Around 1820, John MacAdam, a Scottish engineer building roads, upended the premises about proper road construction. Rather than place massive stones as the foundation and surface of a road, he determined that the roads could be build of successive layers of fine gravel, rolled in place, often bound together with tar or bitumen and crushed stone. The ordinary ground would support the weight of traffic and the road would last if designed with proper drainage.