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Most of us in the transportation field are familiar with the story of Roman roads and bridges. History tells us that more than 250,000 miles of roads were constructed between 350 BC and AD 150, with 50,000 miles being paved.

While impressive, the story of Roman roads goes much further, and resonates with elements we consider only to be associated with “modern” streets and highways.

Roman roads, for example, were classified according to function, constructed to strict design standards, made with quality materials, and were scrupulously maintained.

Some of these facilities remain in use today – boasting a service-life exceeding 2,000 years.

Classification

Viae publicae, consulares, praetoriage or militares (public roads) were constructed largely at public expense. They were commissioned by a “censor”, a territorial governor, or the military; were named in their honour; were administered by “commissioners” and maintained by “contractors”, who were paid by through the proceeds of tolls levied on neighbouring land-owners.

The viae regales or Roads of the Persian Kings (who are widely-credited with having organized the first system of public roads), for example, translates literally into the modern “King’s Highway”.

The term viae militariae or “war-way” needs no explanation. Roman roads allowed for the rapid movement of military forces to counter internal and external threats – a concept which foreshadowed the construction of the Dwight D. Eisenhower National System of Interstate and Defence Highways in the United States or as it is more commonly-known, Interstate Highway System, by more than two millennia.

Unfortunately, during the fall of the empire, these same roads also allowed a rapid advance by the conquering barbarian hordes; and they likely didn’t stop to pay tolls.

Viae privatae, rusticae, glareae and agrariae included private or country roads, originally constructed by private individuals, in which their treasure or toil was invested, and who had the power to dedicate them to the public use. Such roads benefited from a “right of way”, in favour either of the public or of the owner of a particular estate.

Viae vicinales comprised roads at or in villages, districts, or crossroads, leading through or towards village. Such roads were considered public or private, according to the fact of their original construction. Such a road, though privately constructed, became a public road when all memory of its private constructors had perished – the Roman equivalent of the 99-year lease enjoyed by 407ETR.

Engineering

Roman roads were constructed to be immune to floods and other environmental hazards.

The laws of the Twelve Tables, dated to approximately 450 BC, specified that roads shall be 8-foot wide where straight, 16-foot wide where curved, and was the geometric design guide of its day. Local authorities gave preference to building roads as straight as possible, in order to build the narrowest roads allowable, and thus save on labour and materials.

Even in 450 BC, agencies, designers, and contractors were all watching the bottom line.

There were several variations on a standard Roman road. Most of the higher quality roads were composed of five layers, placed after the roadbed was excavated to bedrock or a suitable founding surface. Ramming was often used to improve the load-bearing properties of native soils. The finished road stood proud of the surrounding terrain, facilitating drainage.

Higher-quality roads utilized concrete extensively, which the Romans had discovered. Mortar and stones were mixed in the adjacent ditch; an impromptu mobile batching plant.

The bottom layer, called pavimentum, was one inch thick and made of mortar. This provided a water-resistant base.


 Above the pavimentum were four strata of masonry. The layer directly above was called the statumen. It was one foot thick, and was made of stones bound together by cement or clay.

Above that, there were the rudens, which were made of ten inches of rammed concrete. The next layer, the nucleus, was made of twelve to eighteen inches of successive thin layers of concrete, which were placed and rolled to ensure consolidation.

A summa crusta of silex or lava polygonal slabs, one to three feet in diameter and eight to twelve inches thick, were laid on top of the rudens. The crusta was crowned for drainage. The final upper surface was made of concrete or well smoothed and fitted flint.

Generally, when a road encountered an obstacle, the Romans preferred to engineer a solution to it rather than redirecting the road around it. Bridges were constructed over all sizes of waterways; marshy ground called for the construction of raised causeways with firm foundations; and hills and outcroppings were frequently cut or tunnelled through rather than avoided. The tunnels were made with square hard rock block.

Laws

Roman law defined the right to use a road as a servitus, or claim. This claim established the right of all persons to use a footpath across private land, and to use a carriage track under a “right of driving”. These laws created the concept of a public domain for all persons, and made it distinct from the private domain or private property.

Unfortunately, too many road users to this day interpret driving to be a “right” (perhaps citing Roman law) rather than a privilege to be earned through competence, compliance, and a sense of community.

Financing

Financing road building was a Roman government responsibility. Maintenance, however, was generally “downloaded” to the provinces. Inter-city roads were under military jurisdiction, while roads within municipalities were a local responsibility.

Under the levy system, neighbouring landowners could be required to furnish labourers for the general repair, or to keep in repair, at their own expense, a certain length of public road passing through their respective properties.

Road Tolls

Despite the fact that many roads were in the public domain, and a right of usage was granted to citizens, tolls abounded, especially at bridges. Often they were also collected at the city gate.

Freight tolls were levied according to weight, ostensibly based on the increased wear-and-tear they imposed on the road network. Freight costs were made still more expensive by import and export taxes between cities and provinces.

This should all sound very familiar to today’s trucking industry.

Vehicles and Transportation

Outside the cities, Romans were avid horse-riders and rode on or drove quite a number of vehicle types.

Carts driven by oxen were used. Horse drawn carts could travel 40 to 50 km (25 to 30 miles) per day. Pedestrians could walk 20 to 25 km (12 to 15 miles) per day.

Roman vehicles may be grouped as cars, coaches, and carts. Cars were used to transport one or two individuals, coaches were used to transport parties, and carts transported cargo. In all cases, the tires were made of iron.

Of the cars, the most popular was the carrus (“car”), more commonly known as a chariot. It carried a driver and a passenger. A carrus of two horses was a biga; of three horses, a triga; and of four horses, a quadriga, which likely made it the Mustang GT of its day.

A more luxurious version, the carpentum, transported women and officials. It was drawn by mules. A lighter version, the cisium, was drawn by one or two mules or horses. It came with a driver and was the taxi-cab of its day.

Of the coaches, the mainstay was the raeda, which had four wheels, and resembled a wagon of the old west. It carried several people with baggage up to the road-legal limit of 1000 Roman Libra (pounds), the modern equivalent 327 kg. It was drawn by teams of oxen, horses or mules, and was the intercity bus of its day.

Of the carts, the mainstay was the plaustrum. This was simply a platform of boards attached to wheels and a cross-tree, like a flatbed truck. The wheels, or tympana, were solid and were several centimetres (inches) thick. The sides could be built up with boards or rails. A large wicker basket was sometimes placed on it. A two-wheel version existed along with the normal four-wheel type called the plaustrum maius. It was the equivalent of the modern-day over-the-road truck.

The military used a standard wagon. Their transportation service was the cursus clabularis, named after the standard wagon it employed. It transported the impediments, or baggage, of a military column – and was the Roman deuce-and-a-half (three-tonne truck) of the time.

Wayfinding

Milestones divided Roman roads into numbered miles. The modern word mile derives from the Latin milia passuum, “one thousand paces”, which amounted to 4,841 feet (1,480 m).
A milestone, or miliarium, was a circular column on a solid rectangular base, set more than 2 feet (60 cm) into the ground, standing 5 feet (1.50 m) high, 20 inches (50 cm) in diameter, and weighing more than 2 tons.

At the base was inscribed the number of the mile relative to the road it was on. In a panel above, at eye-height, was the distance to the Roman Forum, along with information about the officials who made or repaired the road.

Romans and ancient travelers in general did not use maps. They were hard to copy and were not in general use.

On the Roman road system, however, the traveler needed some idea of where he was going, how to get there, and how long it would take. The itinerarium filled this need.

In origin it was simply a list of cities along a road. To sort out the various lists, the Romans drew diagrams of parallel lines showing the branches of the roads. Parts of these were copied and sold on the streets, by the ancient equivalent of the Automobile Association. The very best “maps” featured symbols for cities, way stations, water courses, and so on.

These maps did not represent landforms but they served the purpose of a simple schematic diagram for the user – not unlike today’s subway maps.

The Roman government undertook to produce a master itinerary of all Roman roads from time to time. Julius Caesar and Mark Antony commissioned the first known such effort in 44 BC.

Zenodoxus, Theodotus and Polyclitus, three Greek geographers, were hired to survey the system and compile a master itinerary. This task required over 25 years. It must have been a cost-plus contract. The result was a stone engraved master itinerarium set up near the Pantheon, analogous to today’s official roadmap, from which travelers and itinerary sellers could make copies.

Roadside Services

Tolls were only the charges for using the roads. The cost of services on the journey went up from there. Roadside services, then as today, commanded premium price according to their convenience, and the road users’ needs and wants.

Way stations providing refreshments were maintained by the government at regular intervals along the roads. A separate system of mount-changing stations for official and private couriers was also maintained. This allowed a dispatch-rider to travel a maximum of 800 kilometres (500 mi) in 24 hours by using a relay of horses.

Non-military officials and people on official business generally had no legion at their service. The government maintained way stations, or mansiones (“staying places”), for their use. Passports were required for identification. Mansiones were located about 15 to 18 miles (25 to 30 km) apart.

There the official traveler found a complete villa dedicated to his use. Often a permanent military camp or a town grew up around the mansio.

For non-official travelers in need of refreshment, a private system of “inns” or cauponae, were located near the mansiones. They performed the same functions but were somewhat disreputable, as they were frequented by thieves and prostitutes.

Genteel travelers needed something better than cauponae. In the early days of the viae, an unofficial provision existed, which held that houses placed near the road were required by law to offer hospitality on demand.

Frequented houses no doubt became the first tabernae, which were hostels, rather than the “taverns” we know today. As Rome grew, so did its tabernae, becoming more luxurious and acquiring good or bad reputations as the case may be.

A third system of way stations serviced vehicles and animals: the mutationes (“mount-changing stations”). They were located every 20 to 30 km (12 to 18 miles).

In these complexes, the driver could obtain food, water, and stable-space for his animals; or purchase the services of wheelwrights, cartwrights, and equarii medici, or veterinarians as needed. Today’s modern truck-stops serve a similar function.

Two postal services were available under the empire, one public and one private. The Cursus publicus carried the mail of officials by relay throughout the Roman road system. The vehicle for carrying mail was a cisium with a box, but for special delivery, a horse and rider was faster.

The postal service was a somewhat dangerous occupation, as postmen were a target for bandits and enemies of Rome.

Private mail of the well-to-do was carried by tabellarii, an organization of slaves available for a price. Today we call them couriers.

Centurions of the Roman legions generally marched, officers rode horses, and wagons carried their equipment, baggage, and supplies. The formations broke step when crossing bridges, the dangers of harmonic loads on structures having already been recognized.

Summary

Rome’s network of public roads were established by law; financed by tolls and taxes; and engineered, built, and maintained to move people, goods, mail, and armies across an empire. 

They were administered by a central government, policed by a military, and maintained by a private-sector industry of contactors.

The drivers of the cars, trucks and buses of the day, along with the riders and pedestrians, navigated using copies of directions and a system of way-finding signposts not unlike that which we use today.

During their journey, official travelers stopped at public facilities. Everyone else purchased food, beverages, animal care, accommodations, and repair services from private-sector businesses established specifically to serve their needs.

One must wonder if a Roman citizen, shown our modern network of highways, might remark:

“Two millennia…and so little change?”
 

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