Paving the Way: The Long History of Roads

Reorganized in the fifth century BC, likely under Darius I, this Achaemenid Persian highway ran roughly 2,700 kilometres from Susa to Sardis. It was equipped with 111 posting stations stocked with fresh horses, so a mounted courier could cross the whole route in nine days, a trip that took about ninety days on foot.

Built from around 300 BC onward, the Roman network grew to more than 400,000 kilometres, over 80,500 of them stone paved, surveyed with the groma and built on layered, drained foundations. Twenty nine major highways radiated from Rome itself, built mainly to move armies, administrators and trade across the empire.

The Persian Royal Road predates Romes Via Appia by about two centuries, so on strict chronology Persia built the first engineered long distance road. Most popular accounts still credit Rome instead, because its layered foundations, drained surfaces and surveying methods became the template later road builders followed. This atlas records the dispute honestly rather than picking a winner.

Not a single road but a shifting web of caravan tracks and sea lanes, this network connected East Asia to the Mediterranean world from roughly the second century BCE into the fifteenth century CE. It carried silk, spices and precious metals, and it carried ideas too, including the spread of Buddhism, gunpowder and paper making.

Linking Central Asia to South Asia for at least 2,500 years, this roads precursor was built by Chandragupta Maurya in the third century BC, reportedly inspired by the Persian Royal Road already on this trail. The modern road still runs about 3,655 kilometres, from Teknaf in Bangladesh to Kabul in Afghanistan.

This Scottish engineer developed macadam, a road surface built from layers of compacted, angular crushed stone that shed water without needing the deep stone foundations earlier road builders relied on. Britain, then Europe and North America, adopted it through the early and mid nineteenth century, and it stayed the standard road surface until asphalt refined it further.

A Scottish civil engineer who built roads, canals, bridges and aqueducts across Britain, including the Menai Suspension Bridge. In 1820 he became the first president of the Institution of Civil Engineers, helping turn civil engineering into a formal profession rather than a trade learned only by apprenticeship.

Authorized by the Federal Aid Highway Act of 1956, this network of controlled access highways was the largest public works project in American history at the time it was built. It reshaped how Americans commuted and shipped goods, and reshaped the shape of American cities around long distance car and truck travel.