Until a century ago, road users had to endure the inconvenience of dust. But in 1901, John Loudon McAdam, a Scottish engineer invented a process of building roads using tar and crushed stone. He called the process macadamisation. The product of this process was tarmacadam. This is according to Justaquote, a United Kingdom online information service.

When McAdam invented tarmacadam, it was during the days of horse-drawn vehicles. This is according to the article "The man who invented Tarmac” by British Broadcasting Corporation (BBC). Later when cars started to become common on the road, it was discovered that tarmacadam was not strong enough to withstand the weight.

In 1902 Edgar Purnell Hooley an English surveyor discovered the idea of making long-lasting material for road construction. This is according to the article "Tarmac sealed road surface” by Made up in Britain, an online knowledge resource on British inventions.

BBC, Made Up in Britain and other sources say that the idea came to Hooley by accident. The story goes that a barrel of tar had burst open over a road and in order to prevent the tar from spreading, the area was covered with waste slug. As a result, the road became harder and dust-free. Hooley noticed this and began the process of making tarmac by heating tar, adding slag and then mixing it with stone.

He gained copyrights for making tarmac. However, he didn’t change the nameof the process or that of the end product, choosing to pay homage to McAdam.

Because of his decision to pay respect to McAdam, the road-making company was originally called TarMacadam Syndicate Ltd. This is according to the article "Tarmac history: from lucky accident to aggregates giant” by Graham Ruddick, a British property and industry consultant.

One would expect that such an invention would become quickly popular. However, this was not the case. In the article "Tarmac” by Wolverhampton History Website, the failure of the invention to gain immediate success is attributed to Hooley’s lack of marketing skills.

In 1905, Alfred Hickman, a British Member of Parliament bought the company, named it Tarmac and re-launched it. The company has been successful since then. This is evidenced by the fact that the word "tarmac” is used to describe all the macadamized roads.

Tarmacking roads has contributed a great deal to road safety, shortening of distances and making cities neat. For example, one of the reasons why Rwanda is enviably neat is because of the abundance of tarmacked roads.