Rome: Roman Technology In Creating Roads

Abstract

Roman technology created roads that lasted thousands of years, their longevity still visible to us today. Their roads are perhaps their most impressive feat. To understand how the roads were so successful; this paper will discuss their origins, uses, and engineering that let such speed and efficiency be achieved. It will include pictures of the tools used and the finished product. There were many variations of roads including Viae Terrena, Viae Glareae, and Via Munita. Roman civilization lasted for thousands of years with roads every step of the way. From humble beginnings to the grandeur of the empire, we will follow the vital arteries and learn how the ancients battled the same problems engineers face today.

Introduction

The Romans have long been revered for their engineering feats. Their civilization was the known world for thousands of years and lasted from ancient times until just before Columbus walked ashore in the new world. Their longevity and continued power were only possible through these engineering feats. Among the numerous amphitheaters, temples, and aqueducts one system stood out. Rome’s road network enabled trade that built an economy, let legions march thousands of miles, and kept the empire together. These roads were built to last, and last they did. We still see them standing today and we even use some of the originally surveyed routes as modern roads. This paper will discuss the history of the roads, the geography that created the need for them, the geography they had to overcome, and the engineering behind them.

Discussion

Rome did not begin as a large empire. It was founded (according to myth) in 753 BCE as a city-state ruled by kings. Their expansion was slow in the early years because of the surrounding peoples like the Etruscans, Samnites, and Greeks. The first roads were constructed during this time and made of tamped dirt and cleared brush. They were fine for the short distances and low demands on the kingdom but would eventually need upgrading. The need and opportunity finally arose when the Romans, now the Republic, fought for the central area of Italy during the Samnite Wars. They started construction on the Appian Way in 312 BC during the second war with the Samnites. This came after the Romans experienced major logistical problems during the first war. It was Rome’s first paved road, constructed to solve the logistical problems. During the Second Samnite War, the road served its purpose. Rome could move its forces more effectively and won the war. This success led to the completion of roads all across the Republic and later the empire starting with Augustus. The roads got more efficient as time went on and as the Romans learned better techniques for building.

Types

Because the republic and empire were so diverse, different types of roads served different functions. Some roads were advanced than others, the lowest road being the dirt path or the “Viae Terrena.” They usually formed from people and wagons traveling over the same route many times. These were by no means Rome’s premier roads. They were usually used for local traffic and connected to larger, paved roads. The “Viae Glareae” were dirt roads that were covered over with gravel. These accommodated more traffic but still were not quite highways. The impressive roads we think of are the “Viae Munita” which upon closer inspection resemble the roads we build today in terms of features. Those viae were normally public roads built at the taxpayer’s expense, although there was still a toll on them. Roads might also be built for military use or by private citizens as a for-profit toll road. Whoever owned the private road decided who could travel on it. Toll booths were placed at strategic locations like bridges or city gates where avoiding them would be inconvenient.

Similarities to the Modern Highway

Roman roads were fairly similar to their modern counterparts in terms of amenities and features. There were mile markers telling travelers the distance to the nearest way station or landmark. The way stations had restaurants and inns for travelers to stay. They also had changing stations for horses, kind of like a gas station, where travelers could get on a new horse or attend to their animals. Way stations sometimes led to the creation of whole towns. The roads had deep foundations, paved surfaces, proper drainage, landscaping, sidewalks, toll booths, rest areas, hotels, restaurants, and stores. Pretty much anything a modern road had, the Romans had a version too.

Uses/Effectiveness

The empire ended up having about 250,000 total miles of roads with 50,000 of that paved. As previously stated, these roads connected all corners of the empire from the Euphrates to England. The construction of Roman roads was no small feat. It involved other massive works of engineering because difficult terrain required bridges, tunnels, viaducts, etc. On top of that, there were basic excavation and drainage problems to sort out like where to put all the dirt or send the water. They had both an inward and outward effect on the empire. The legions and culture flowed out past the borderlands and the money and goods flowed in and then around the empire. These roads were key to keeping Rome in control of such vast amounts of territory.

The new roads let troops and supplies move incredible distances, especially when compared to paths. Trade boomed when merchants gained the ability to move goods at a good speed for a toll. Fresh goods were moved from the agriculturally rich lands in the south and sold elsewhere in the empire. The trade network created interconnectedness never before seen.

The military aspects of the road were the main benefit. They united and consolidated the conquests of the Roman empire, all the way to the edges of the known world. No matter how far a town was, troops could always arrive. A baggage train could be easily carried with a legion as it marches along a road. Also, the legion could easily set up camp for the night without needing to search in advance for a place to set up.

Laws and Planning

Although whoever built the road, whether public or private, could alter the specifications somewhat depending on the geography and resources of the area. The types of roads generally took on the same forms. Mile markers were placed along the road at intervals of one Roman mile or 1,000 paces. They were five feet high stone columns which indicated the mile number, the distance to Rome, and the distances to the nearest towns and way stations. The person who did the work on the road would also put their name on the makers. It was also required by law for way stations to be set up around 16-19 miles apart. However, they sprang up for economic reasons anyway. The data I discuss in the engineering section is the general standard throughout the empire.

Engineering

Figure 1. Dioptra, chorobates, and groma demonstration (ferrovial.com 2018)

The dioptra (on the left) is similar to our tachymeter or theodolite. It measures vertical and horizontal angles.

A chorobates (top right) was used to level the ground. The level in use today is an evolution of this technology.

The groma (bottom right) is a vertical pole with a cross mounted on top at ninety-degree angles which could turn. It was used for checking alignment over many miles.

The construction process for paved roads was generally as follows. To start, crews would be sent to find the precise direction between two points, they then went to create a straight line between them. Straight lines were seen as more efficient and direct than a road curving around obstacles. This ended up with roads that just went straight over or straight through mountains. Eventually, they realized gradients of up to 20% in mountainous country was impractical for people and animals alike. Later roads fixed this issue when surveyors started to factor in gradient. Curves were still more of a last resort though. To keep the line straight, surveyors used a groma. As shown by the picture above, a groma is a cross with evenly weighted weights on each end. The user would look down the horizontal cross on top of the instrument at ranging poles lined up in the distance. The groma was used to make sure the ranging poles were in a straight line. See (figure 1) above for a visual demonstration.

Figure 2. Roman road cross-section (stackexchange.com 2015)

After the route was planned with the groma and measured with the dioptra, excavation started on the road’s foundation. The depth varied, but swamps, for example, needed a 3-6 foot trench. Once the dirt was excavated by workers, slaves, or legionaries; the new bottom was tamped down and leveled with a layer of sand added to create a flat surface. Again, composition then varied based on materials of the region. However, larger stones packed first to make a solid base that was possibly cemented together. On top of that were smaller stones also possibly cemented together. Further still was sand (depending on availability) to make a genuinely smooth surface checked by their version of a level, the chorobates. Concrete might be added depending on sand availability. Paving stones of flint, lava rock, or marble formed the hard surface. On all paved roads, the center was a foot higher than the sides. This created runoff and the water cleared almost instantly. Drainage ditches were built into the side to accommodate this runoff. See figure 2 for a cross-sectional view of an average road. The width of a Roman road is eight Roman feet minimum and two and a half times that width on a curve. Sometimes gravel sidewalks were used (usually on private roads) for pedestrian traffic. Brush also needed to be removed to deprive bandits of a place to hide and so growth did not affect the road. Once the distances and the miles were calculated, markers and way stations were set up.

Conclusion

The roads were the backbone of the Roman economy and military. Fast troop movements and a stable economy kept the empire together for hundreds if not thousands of years. The roads themselves survive into modern times and even outlasted the civilization that built them. Their effectiveness in resisting wear and tear from use and the elements came down to simple but effective engineering techniques. For the most part, the only problem was the gradient in some sections which was solved. These causeways of commerce look strikingly similar to our modern roads with their way stations and miles markers while lasting much longer. The reader should note how advanced the Romans were. With relatively simple tools they conquered the same problems we face today. It is important to note that we are not inherently smarter than them, we are just standing on their shoulders. So, of course, we can see a little further.