Short answers, pulled from the story.
John Loudon McAdam was a Scottish civil engineer born in Ayr on the 23rd of September 1756. He invented macadamisation, a method of building roads with a smooth, hard surface using controlled materials of mixed particle size and a convex camber to drain rainwater away from the foundations.
McAdam was born in Ayr, Scotland, on the 23rd of September 1756. He died in Moffat, Dumfriesshire, on the 26th of November 1836, while returning to his home in Hoddesdon, Hertfordshire.
The macadam method raises the road above the surrounding ground and builds the surface from crushed stone bound with gravel, laid on a firm base of large stones. A slight convex curve, called a camber, channels rainwater off the road before it can penetrate and damage the foundations.
Tarmac is a contraction of Tar Macadam, named after McAdam's method of stone-surface road construction. Coal tar was later added by others to bind the stones together. McAdam's own direct connection to tar was only commercial: his colliery supplied coal to the British Tar Company of Archibald Cochrane, the 9th Earl of Dundonald.
The National Road was the first macadam road in North America, completed in the 1830s. By the end of the nineteenth century, most of the main roads in Europe had also been built using McAdam's process.
Professional jealousy led Parliament to cut McAdam's expense grant from £5,000 to £2,000 in 1827. His efficient road management had exposed corruption and abuse of road tolls by turnpike trusts that were run at a deliberate loss despite collecting high receipts.