The Long History of Roads

Every work — at a glance

• The Roman Road Network

  Fifty to eighty thousand kilometres of layered, cambered, famously straight highway, built by the army to move the army — with trade, mail and Christianity travelling as a side effect.

• The Silk Road

  Not a road and not silk: a shifting network of relays linking China to the Mediterranean, which moved paper and printing west, Buddhism east, and the Black Death both ways.

• Trackway

  The oldest kind of road — a route worn in by use, and where the ground was marsh, engineered: the Somerset Sweet Track is dated by tree rings to 3807 BC.

• Ridgeway

  A track along a ridge crest, because the tops are dry and open while prehistoric valleys were wooded and boggy. England's Ridgeway has been walked for roughly 5,000 years.

• Holloway

  A 'hollow way' — a lane worn metres below the surrounding fields by feet, hooves and rain over centuries, until the track is a green tunnel between banks.

• Corduroy Road

  Logs laid crosswise over swamp so a wagon can cross — ribbed like corduroy cloth, brutal to ride, and rotting from the day it is built.

• Gallery Road

  A road cut as a shelf into a cliff face with rock left overhead, for places with no ground to build on — Switzerland's Axenstrasse is the classic.

• Macadam — John Loudon McAdam

  John McAdam's layered crushed-stone surface, about 1820: no heavy foundation, just small angular stone kept dry by a camber. Add tar and it becomes tarmac.

• Pavement

  From the Latin for a beaten floor — to an engineer, the whole layered structure that spreads a wheel's load, not the black skin on top of it.

• Asphalt

  Crushed stone bound with bitumen, the residue left when crude oil is refined. Flexible where concrete cracks, and millable and reusable when it wears out.

• Milestones

  Roman stone columns counting distance in thousand-pace miles, inscribed with the emperor who paid — measured from the Golden Milestone Augustus set up in the Forum.

• The Persian Royal Road — Darius the Great, 5th century BC

  Darius's 2,700 km highway with relay stations, so a courier crossed it in nine days and an ordinary traveller in three months.

• The Inca Road System — the Inca empire

  40,000 km built by an empire with no wheels and no horses: stairways, cliff ledges, rope bridges, and chasqui runners carrying knotted quipus.

• The Grand Trunk Road — Mauryan empire, rebuilt by Sher Shah Suri

  South Asia's 2,500 km spine, in use since the third century BC; Sher Shah Suri added the inns, wells and shade trees that made it usable.

• The via Francigena — medieval pilgrims

  The pilgrim road from Canterbury to Rome, walked over months by people for whom shortening the journey would have spoiled it.

• The Trail of Tears — United States government, 1830s

  The 1830s forced march of the Cherokee over 1,600 km to Oklahoma: a route used to remove people rather than to connect them.

• The Ho Chi Minh Trail — North Vietnam, 1959-1975

  A web of jungle tracks through Laos and Cambodia that years of bombing could not close, because there was nothing single to destroy.

What to know

1. 01
   A road is a job, not a surface. The Romans counted a paved highway and a marked desert camel path as the same kind of thing, because both were maintained connections with way stations along them — so the question to ask about any route is what it does, not what it is made of.
2. 02
   What a road carries outruns what it was built for. Rome laid its network for legions and got trade, mail and Christianity; the Silk Road moved paper west and Buddhism east and the plague along with them. A channel does not choose its cargo.

Across subjects