The end of an era?
John McAdam's lasting legacy for motorists around the globe
We’ve published a lot about roads, tarmac and tyres over the years, but it has been a long time since we looked at the guy who made it all possible: John McAdam.
It is hard to believe, but before the Industrial Revolution, no real progress had been made on road building technology since the Romans went bust.
Given that a wagon and horses (or camel) were the only overland transport, you might have though someone would evolve the pot-holed mud tracks, but it wasn’t until one of the fathers of the cast iron age, the engineer Thomas Telford picked up on some theoretical designs for roads with a hardcore base and a water run off camber, that anything actually got done.
Telford’s methods, though effective, needed a lot of work. The system was fussy, it required a lot of masonry work and took a long time to lay. His theories on drainage, however, was a major step forward in road design.
Another Scot, John Loudon McAdam developed a far simpler and more effective idea. He had been working as a highways engineer and surveyor in Bristol, England for several years and theorised that complex base cores were unnecessary.
Using far less materials, McAdam realised that a decent, paved road which ensured smooth running and decent water roll-off could be built for a fraction of the cost of Telford’s complex method.
Straight away, he realised the potential of the development, and he wasted no time in preparing a report which he sent to the government, where he was made Chief of Public Works. Not everybody was so pleased though.
Most major highways in the UK at the time operated as toll roads, and a large programme of works suddenly exposed their corrupt wrongdoing – and as a result of upsetting the wrong people, McAdam’s grant was slashed.
It didn’t make any difference. By the time the rail network started to be built, the toll road system was seen as a hindrance to free enterprise and was abolished. The McAdam process by this time covered every toll road in the UK – and it is still the way we build roads to this day.
The final piece of the puzzle came when the first cars were starting to roam the highways.
A man called Edgar Hooley worked out that an even smoother surface could be achieved by binding the McAdam with tar – hence Tarmacadam – or Tarmac as it became known. The rest of the story is , as they say, a well travelled road.
Well, that’s about it from me. I hope you have enjoyed the magazine over the past three years and I wish all of you the very best for the future.