 British turnpike builders began to realize the importance of selecting clean stones for surfacing while excluding vegetable material and clay, resulting in more durable roads.By the late 18th and early 19th centuries, new methods of highway construction had been pioneered by the work of three British engineers, John Metcalf, Thomas Telford and John Loudon McAdam, and by the French road engineer Pierre-Marie-Jérôme Trésaguet.The first professional road builder to emerge during the Industrial Revolution was John Metcalf, who constructed about of turnpike road, mainly in the north of England, from 1765.