We cannot credit a single person for inventing roads but Pierre-Marie-Jérôme Trésaguet deserves a mention. A French engineer, he sat down to write guidelines for the construction of roads. In 1775 he became Inspecteur Générale for roads and bridges in France and the country began updating paths and tracks. Trésaguet insisted on excavating the ground, installing a layer of large rocks and then adding finer layers of gravel on top, all with drainage channels by the side. Like that, horse-drawn carriages could ride smoothly across mud-free roads as water would now drain away.
The next prominent name in early road construction is John Loudon McAdam, a Scot whose name lives on today thanks to macadam and tarmac. Macadam is the use of soil and stone that is then rollered into place to form a compacted layer that resists the passage of traffic, horseshoes included. This technique is still in use the world over and today cycling races use such roads in the strade bianche of Tuscany or the Colle delle Finestre, a regular in the Giro d’Italia which was built for the Italian army.
[Imagine if the road could be patented (It no doubt could if it were "invented" today). Evolutionary development happens all the time. Real leaps in understanding, design, or application are rare. Chip seal roads suck because they are "tweeners"… neither gravel road nor pavement. They catch you unaware, lulling you to sleep with well packed sections when a sudden pile of loose stone or some fresh oil does you in. feh.]
Source: The Inner Ring