Today’s streets have a harder time than their ancestors. Instead of wooden legs, hooves and wheels, semi trucks and SUVs are shouldered. As we have developed new modes of transportation, we have also changed the nature of the routes we travel, turning gravel roads into paved superhighways. Challenges like extreme weather and carbon emissions mean our highways need to evolve even further, so engineers are turning to futuristic solutions to keep traffic moving. Here is the story of this long and winding journey and its subsequent development.
People have been cutting down trees and burning bushes to transport food and attack our enemies for more than 10,000 years, but the Mesopotamians invented some of the first paved roads to make cities more convenient for transit, around 3,000. Workers made thousands of identical mud bricks, dried them, and then laid them into roof tiles. To prevent the roads from collapsing every time a cow kicked them, they glued the blocks together with bitumen, a semi-sticky natural oil that we still use as a binder in asphalt. But this ancient population worked labor-intensively only on streets of religious or military importance.
While not all road technology could lead back to Rome, the Roman Empire built some of the longest and longest lasting roads in the ancient world. The builders buried layers of stone and gravel in the ground for stability. Closer to towns and in other prominent locations, cobblestones covered these layers with hard stone to give a more polished appearance.
At its height, around 100 AD. C., the Empire supervised a total of 50,000 miles of highways that allowed soldiers and merchants to move quickly through Europe and Asia Minor. Some of these dilapidated passages are still functional today. The Appian Way, which stretches 350 miles southeast from Rome to Italy’s east coast, supports vehicular traffic in some sections, though many major repairs have been made over the past two millennia.
2. Sloping Earth
When the Industrial Revolution began in Britain in the 1700s, local governments built longer networks of gravel roads, relying on tolls to finance the construction of new routes. These so-called highways originated in the countryside, stretching from London and connecting cities in England and Scotland. But most of the paths were made of small stones piled on top of mud, which meant that the slightest splash of rainwater could turn rocky paths into muddy mounds of disgusting and dangerous slush.
A civil engineer named John Metcalfe had a plan to make things right. His construction crews slightly sloped the surface of each new street and dug deep trenches on both sides. This provided adequate drainage to prevent road collapse due to excess moisture and to prevent potholes.
Metcalfe went to great lengths to advocate for these design changes. Blind since childhood, he once defied the colonel and he took him to London. Thanks to the rugged terrain, Metcalfe reached the city on foot faster than a military man could get there in his horse-drawn wagon.
3. Compacted gravel and asphalt
In the early 20th century, highways as we know them began to be developed in the United States, replacing dirt roads with durable concrete. But long-distance routes, such as the Lincoln Highway that connected New York and San Francisco in 1923, were sometimes no better than earthen ditches dug in the fields. While riding in the Lincoln with his army escort in 1919, Lieutenant Colonel Dwight D. Eisenhower had an idea: what if it’s better everywhere? When he became president, Eisenhower planned the Interstate Highway System, which took three decades to complete over 45,000 miles of pavement.
The Present: What Lies Beneath Our Wheels
1. Strong foundation
Apartheid-era South Africa was under sanctions and economically marginalized by many other countries, making buying bitumen for the road prohibitively expensive. So the country’s engineers came up with a custom solution that was not only cheaper, but just as effective as traditional methods. Instead of laying a thin gravel base and covering it with half a foot of asphalt, the South African designers relied on a foot-thick layer of stone (soaked in cement) as the base of the walkway, and then laid a 2-inch layer. layer. thick strip of asphalt on top. Trade reopened after apartheid ended in the 1990s, but no one was in a hurry to rebuild the region’s surface: the unique roads proved to be as strong and resilient as those in other countries. The thoughtful and efficient solution was admired by transport officials around the world.