EXCERPTS: During its zenith under the reign of Septimius Severus in 211 C.E., the mighty Roman Empire stretched over much of Europe, from the Atlantic to the Ural Mountains and from modern-day Scotland to the Sahara or the Arabian Gulf. Crucial to maintaining dominion over such a large empire was Rome’s huge and intricate network of roads that remained unparalleled even a thousand years after its collapse.
It is estimated that the Roman road network was more than 400,000 kilometers long, out of which over 80,000 km were stone-paved. Like arteries, these marvelous feats of engineering ferried goods and services rapidly and safely, connecting Rome, “the capital of the world”, to the farthest stretches of the empire, and facilitated troop movements to hastily assemble legions for both border defense and expansion. Encompassing both military and economic outcomes, roads were truly central to Rome’s political strategy.
While the Romans didn’t invent road building, they took this Bronze Age infrastructure to a whole new level of craftsmanship. Many of these roads were so well designed and built that they are still the basis of highways that we see today. These include Via Flaminia and Britain’s Fosse Way, which still carry car, bike, and foot traffic. The answer to their longevity lies in the precision and thoroughness of Roman engineering.
[...] After completing all the geodetic measurements and projections, the Roman surveyors marked the path of the future road using milestones. All trees, shrubs, and other vegetation that might interfere with the construction of the road were razed. Marshes were drained and mountains would be cut through, if needed.
The average width of an ancient Roman road was around 6 meters (20 ft.), although some large public roads could be much wider.
According to the writings of Mark Vitruvius Pollio, an outstanding Roman architect and engineer who lived in the 1st century C.E., Roman public roads consisted of several layers:
• Foundation soil – depending on the terrain, builders either dug depressions on level ground or installed special supports in places where the soil subsided. The soil is then compacted and sometimes covered with sand or mortar to provide a stable footing for the multiple layers above.
• Statumen – a layer that was laid on compacted foundation soil, consisting of large rough stone blocks. Cracks between the slabs would allow drainage to be carried through. The thickness of this layer ranged from 25 to 60 cm.
• Rudus – a 20-cm-thick layer consisting of crushed rock about 5 cm in diameter in cement mortar.
• Nucleus – a concrete base layer made of cement, sand and gravel, that was about 30 cm thick.
• Summum dorsum – the final layer consisting of large 15-cm-thick rock blocks. But more often fine sand, gravel, or earth was used in the top layer, depending on the available resources at the workers’ disposal. This layer had to be soft and durable at the same time. Paved roads were very expensive and were typically reserved for sections located near and inside important cities. When pavement (pavimentum) was used, large cobblestones of basalt laval were typically used in the vicinity of Rome.
[...] Every 15-20 kilometer (around 9-12 mi) or so along a public road, it was common to find rest stops where postmen could change horses for a fresh mount. These government stables were known as mutationes. Alongside these establishments, travelers could expect to find mansiones, a sort of early version of an inn where people could purchase basic lodgings for themselves and their animals, as well as eat, bathe, repair wagons, and even solicit prostitutes. In more busy intersections, these service stations morphed into small towns complete with shops and other amenities.
Roman roads were surprisingly safe. The flow of trade and the taxes that went with it were crucial to the Roman empire, so any disruption caused by bandits and other roadside outlaws was unacceptable. A special detachment of the army known as stationarii and beneficiarii regularly patrolled public roads and manned police posts and watchtowers to monitor traffic. They also doubled as toll collectors.
Roman roads tended to roll through sparsely populated areas, and special attention was given to clearing vegetation and digging ditches along the sides of the road. This reduced the cover that bandits could use to ambush carts and law-abiding citizens.
[...] Although suffering from major deterioration due to neglect, Roman roads continued to serve Europe throughout the Middle Ages. In fact, Roman road-building technology wasn’t surpassed until the late 19th century... (MORE - missing details, graphics)