The Construction and Use of Ancient Roman Roads

By Raina Roemhildt

Introduction

There is a classic saying of “All Roads Lead to Rome”. As a tourist or travel junkie, that might mean to you as a calling to go visit the eternal city; gouging yourself with gelato and cappuccinos, throwing a coin into the Trevi fountain, and crossing another destination off of your bucket list. However, to ancient Romans, “All Roads Lead to Rome” was taken as a literal phrase.

To anyone with the slightest knowledge of Roman history, Rome was known as a conquerer. The nation consisted of a strong army, a very wealthy leadership, and engineering that surpassed all others. How does a civilization begin to build more off of that? The answer lies within their roads. Reaching vast locations all around the country of Italy, Rome was as interconnected as modern day cities. Each road built meant more areas to send armies to take over land, generating more wealth and more opportunities.

If that doesn’t impress you enough, the fact that you are able to visit these roads today should. For example, the Via Appia Antica – the longest and oldest Roman road – is still in use today. Over 2,000 years later and these roads are still supporting tourists and cars.

How were these roads built to last so long? What is an ancient Roman road like today? In this report, I will cover these questions within three major sections; the construction of ancient Roman roads, major roads and classifications, and the Via Appia Antica.

The Construction of Ancient Roman Roads

The greatest example of a well built road is the ability to visit and walk on it over 2,000 years later. The construction of ancient Roman roads is a guide to a durable craftsmanship and material use, to which most of we still use today. Whether it’s been military troops, travelers, animals, weather, or tourists: these roads have seen it all. What went into the construction of these roads, who used them, why were they built in such specific locations, and what traits do we still use today?

Building Process

The process behind building a Roman road is made out of layers (Pavica, 2024). The crew begins by digging parallel trenches named “scoop-ditches” along the main road way, keeping retaining walls up on both sides of the new road. These scoop-ditches assisted with the structural integrity of the road, helping the road drain when it rains. The storm drains were dug around 40 feet apart. Between the two scoop-ditches would start the main road: the crew digs a ditch 6-9 feet deep, or reaching bedrock and firm ground. This ditch is called the “fossa” (Cartwright, 2023). Using leftover earth from digging the storm drains, the crew packs a 3 foot layer into the bottom of the fossa, creating a foundation for the new road. Layered on top of this is sand or dry earth, called the “pavimentum” labeled as layer “A” in figure 1 below, to level the surface. 

The main construction begins, following the four common steps of every Roman road: the statumen, rudus, nucleus, and summum dorsum (Pavica, 2024). On top of the pavimentum – the sand layer from previous – is the statumen. The statumen is composed of fist-size rock, averaging at least two inches in size. This layer was put down 10-24 inches thick (layer “B” from figure 1). On top of the statumen is the rudus, a nine inch thick layer of pottery shards or stone gravel mixed with lime mortar creating a type of concrete (layer “C from figure 1). The nucleus is next, a mixture of sand, gravel and lime to create concrete, all compacted together with a roller to sit 12 inches thick (layer “D” from figure 1). In some cases, the nucleus is the top layer of the road. To finish off the layers is the summum dorsom: a six inch layer of wet concrete and large flat stones in lime mortar (Layer “E” from figure 1). This layer has a slight curve to it for drainage purposes, and would increase the longevity of the road with weather-related issues (Cartwright, 2023).

Roman roads were more similar to roads today than we think. They would be lined with curbs built by upright slabs fitted into the sides after the rudus layer to hold the paving stones tightly in (Pavica, 2024). Each road would have mile markers, named “milliaria” or “lapides”, to notify travelers to passing one Roman mile; 1,000 paces equal to 4,850 feet (Cartwright, 2023). These markers were built out of marble or granite, and also listed the official who was in charge of that road section, repairs, and the current emperor or consul (Cartwright, 2023). In the Roman Forum, Emperor Augustus had placed a “golden milestone”, which can be found near the Temple of Saturn. 

Built by packed gravel, footpaths and sidewalks were included along the sides of the road. Along with these sidewalks was placed a higher block to stop traffic from running into the side. The blocks were placed around 12 feet apart, and also assisted travelers to step up and mount horses or pack animals (Cartwright, 2023). Busier stretches of roads had areas for travelers to pull over and rest, just like rest stops you see on busy highways today. Along with these pull off areas were state-run inns – houses for travelers to stay and rest while they were on their journey. These rest stops were called “statio’s”, and could be found around every 10 Roman miles (Cartwright, 2023).

Some purely Roman additions to roads were ridges for traction, specifically on mountain roads. These traction roads had ruts cut into the stones to guide vehicles and assist with vehicles. In true Roman fashion were arches incorporated into the beginning and ends of popular roads. Since roads were a commemoration of their engineering and building skills, a “triumphal arch” was a necessity to celebrate the completion of another road (Cartwright, 2023). These arches would stand alone and span the entire roadway.

Materials Used

Although the basis of every road was the four layers – the statumen, rudus, nucleus, and summum dorsum – didn’t always mean that they had those materials available. The Romans used whatever materials they could find. The main three were very simple, including sand, concrete, and stones. Roman concrete was made from pozzolana, a type of volcanic ash (Lea, 2019). They would mix two parts of the pozzolana to one part of lime, creating a strong concrete or mortar. With this pozzolana concrete, Romans would mix in more travertine, brick, marble, tuff, or any other broken material to create an extra strength concrete. In the 3rd century BCE, pozzolana began to replace sand in their concrete, and it has been a building staple ever since (Lea, 2019).

Roadway Layouts

The layouts for main Roman highways were built simply for travel time. Romans wanted a straight path for every road (Britannica, 2024). The planning would start at Rome and branch off to all different directions. Heading straight towards their destination, the roads were forcefully built into mountain sides, forests, creeks, and marshes (Cartwright, 2023). Each road was built specifically for speed in mind. As for actual cities, they would build roads based on “centurations”. Centurations, or centuries, was a square comprising 2,330 feet on each side, becoming a city block. The Romans were inspired to incorporate the use of centuries from Egyptian, Etrurian, and Greek construction. This type of grid construction is known as orthogonal town planning. It is important to note that the city of Rome was still not built on a grid, however this construction became known as the standard.

The Construction Crew and Travelers

Roman roads were built from the joint knowledge of surveying, masonry, and the creation of cement and pavement. The roads were built by legionnaires, or citizen soldiers, of the Roman army (Pavica, 2024). The use of soldiers meant that these engineers would already have prior knowledge of roads and bridge construction. The main grunt work of the roads came from slave use, having slaves dig trenches and construct the actual roads (Authors of Roman Roads & Machinery, 2020). 

The primary use of Roman roads was for the Roman military. With all roads connecting to Rome, travel that included transporting all soldiers and military equipment would be completed in record time. Using the highways, a Roman legion could travel 20 miles a day. The use of these roads carried Rome to victory, being able to out-move their enemies and conquer more territory. Alongside military use, the roads were then used for trade, travel, and migration (Authors of Roman Roads & Machinery, 2020).

Major Roads and Classifications

There are multiple main highways stemming out from Rome and different categories that each road is able to fall into. Disregarding the Via Appia, there are four great roads that start off from the Rome area to reach all around Italy. These roads are titled the Via Aurelia, the Via Flaminia, the Via Valeria, and the Via Latina (Cartwright, 2023). Each was built in a different time period and moving in a different direction. Additionally, ever road is classified into 3 different subjects, ranging from entirely public to a private dirt road.

The Four Great Roads
The first of the four great roads is the Via Aurelia. Built around 241 BC, the purpose of the Aurelia was to connect Rome to the Pisa in Tuscany. Shown with the yellow line in figure 2 below, the Via Aurelia measured just over 200 miles moving on a track northwest (Cartwright, 2023). The Via Flaminia, or the “great northern highway of Italy”, is the second of the great roads. Built in 220 BC by consol Gaius Flaminius, the Flaminia is labeled by the purple line in figure 2 and travels to Rimini in the northeast, a coastal town in the north of Italy. Similar to the Aurelia, the Via Flaminia measured just over 200 miles (Messineo, 2002). The Via Valeria is the third of the four great roads, rumored to be a continuation of the Via Tiburtina since it begins in Tibur instead of Rome. There is no known builder to the Via Valeria, however it is assumed consul Marcus Valerius Maximus of the Valerius family built the road in 289-286 BC (Lendering, 2020). The Via Valeria is labeled with the gold line in figure 2 and moves east to Marsala, or what used to be Lilibeo, traveling for a total of 240 miles. The last of the four great roads is the Via Latina. Labeled jointly with the Via Appia on the red line in figure 2, the Via Latina moves south-east and connects to the Via Appia ending at southern Lazio and finishing at a distance of 125 miles. 

Roadway Classifications

Although all Roman roads were built generally the same way, each road could be placed into one of three categories. The general names of the three categories were the Viae Publicae, Viae Privatae, and Viae Vicinales (Smith, 1898). 

The public roads, or Via Publicae, consulares, praetoriae, and militares, include all main roads, or roads constructed and maintained by the public’s expense. These are roads that lead in between towns, to public beaches or seas, or to another main public road (Smith, 1898). The average traveler of a Via Publicae was a basic traveler, military, or any commercial traveler. These roads were placed by commissioners and then repaired by contractors with the public’s money. Via Publicae roads all bear the name of their contractors, since they are not used by one person or built under one family. The construction of these roads is no different than any other road, however there would be more repair costs due to the heightened vehicle and foot traffic. 

Private roads, or Via Privatae, rusticae, glareae, and agrariae, are private and country use roads. These roads have been constructed under private individuals, however the owners still have the power to send them to public use; the purpose of which being to gain the public’s favor (Smith, 1898). Included in this category of roads would be any road leading to housing estates. The subsections of Via Privatae roads include Viae rustivae, meaning secondary roads, viae glareae, translating to prepared but unpaved roads, and viae terrenae, translating to dirt roads. Since these roads were built by the owners of estates themselves, they didn’t always end up being paved with that final summum dorsum layer.

The final category, the Viae Vicinales, are roads at, in, or leading towards villages. These roads can be considered both public and private (Smith, 1898). If the road was originally built privately and named after the constructor, once the constructor had passed away the road would automatically be transferred into the public Viae Publicae category.

Via Appia Antica

The first and most famous of the ancient Roman roads is the Via Appia Antica, or Appian Way. With some parts of the original road still in place, the Appian Way is both a tourist destination and a road still used for vehicles today. 

The History of the Via Appia Antica

Built during the time of the Roman republic in 312 BC, this road was the first major highway to extend out of Rome. The Appian Way was created and named under the ruling of Censor Appius Claudius Caecus, and was built for military movement and trade. The road was built during the Second Samnite War, making the movement of military troops top priority. The construction of this road also increased trade throughout Rome, connecting to eastern Mediterranean countries and increasing the transportation of goods (Steves, 2024). The original section of the Appian Way, just over 100 miles, was the first section to be constructed to Capua. It wasn’t until 244 BCE when additions were extended to Brindisi. This connection increased the Roman empire to reach Egypt, Greece, and other eastern countries (Mussio, 2023). In total, the Appian Way stretched over 430 miles, gaining the title of Longarum Regina, translating to Queen of long-distance roads (Cartwright, 2023). 

Today, the road is visited as both a tourist attraction and a way to travel out of Rome. Starting at the southeastern edge of Rome at Porta San Sebastiano, the first 10 miles are currently preserved as the Parco dell’Appia Antica, a regional park (Steves, 2024). As legend goes, between the area of Porta San Sebastiano to the Domine Quo Vadis Church – 850 meters apart – is where St. Peter had his vision of Christ in 64 AD (Mussio, 2023). Farther down the road, the tomb of Cecilia Metella – the daughter-in-law of the richest man in Rome – is set up. On either side and along the way down the road are ancient pagan tombstones, and underneath are two Christian catacombs: the Catacombs of San Sebastiano and Catacombs of San Callisto. (Steves, 2024). The entirety of the Appian Way is bursting with both Christian and pagan history and is an undersight to Roman tours.

The Construction behind the Via Appia Antica

The Via Appia Antica is around 4.10 meters in width, leaving enough room for ancient vehicles to move in both directions (Mussio, 2023). The original road was built following the four basic steps of a Roman road, having the top layer created from large rock. In 189 BC, the top layer of pavement was replaced with basoli, large basalt stones, that could resist constant travel (Cartwright, 2023). The ancient roads we see today have rocks spread apart and are quite difficult to walk around from use and time, however it’s known that with original roads the rocks are so tightly packed and fitted together that it creates a perfectly smooth surface (Pavica, 2024). 

Case Study: Walking along the Via Appia Antica

I wanted to get firsthand experience along the Via Appia Antica, so by taking the 118 bus I traveled to Porta San Sebastiano to find the beginning of the road. After a mixture of walking and busing further down the road (which is still very much being used as a public highway), traveling past the Domine Quo Vadis Church and multiple bike rental shops, I made my way to an original section of the Via Appia Antica. Labeled with a “State Property” sign shown in figure 3, the sudden change between sampietrini cobblestones to large flat rock was sign enough that I was traveling back 2,000 years. 

The large flat rocks were set awkwardly and unevenly across a four meter wide area, making walking – or especially bike riding – a difficult task. Popular footpaths along the side of the main road (figure 5) had been hollowed out, with travelers choosing to follow the flattened dirt instead of navigating the rocks. Main ancient highways, the Appia Antica included, were known for having gravel sidewalks for their patrons traveling by foot, so I think it’s a valid assumption that these were some of the same footpaths used thousands of years before. 

Staying on the large rock, I notice the straight deep cut rivets (figure 6). These are evidence of the past wear and tear of carts rolling on the road, cutting into the ground. 

Between the large rock and the sidewalks, flat stones have been stood up on their side to create a curb. The stones are placed neatly together, averaging just under one foot long (figure 7).

To my left, there is a large block alongside the road. About four feet tall with a “cap” shape built on top, I have found my first milestone (figure 8). I can’t distinguish through the erosion if there is writing on the milestone labeling mile mark or just random scratching on the rock, but it looks like a triangle etched into the side (figure 9). 

Farther down to the right looks like an ancient statue is laying on the ground (figure 10). It’s set in front of one of the many brick constructed buildings (which I couldn’t find what they were), and showcases a headless ancient figure, dressed in what appears to be a toga.

As I forge ahead on the road, I notice that the ground beneath me starts to change entirely back to sampietrini cobblestones for a stretch of road, back to the large rock, and then into a mixture of the two (figure 11). The new additions of sampietrini are renovations to the road, built in where the large rock has been lost. 

There is no better example of a road still being used than the constant stream of walkers, cyclists, and cars traveling through. My entire time on the road, I always had another person in view, avoided multiple bikers, and stayed out of the way of many cars. The cars were slow and bumpy driving on the large uneven rocks, however still traveling on top of the ruts just as carts would have – 2,000 years ago. 

By the end of my route, I had only walked a quarter of a mile. However, I was able to scout a mile marker, curbs, sidewalks, a statue, and switches from large rock to Sampietrini.

Conclusion

The top bucket list items of any tourist entering Rome probably do not stray too far from popular sights such as the Pantheon, the Trevi Fountain, or the Colosseum. Although visiting a road seems in no way equal to these infamous landmarks, the engineering is just as much to marvel at. The construction behind these roads, built strong enough to still be used 2,000 years later, is incredible. A simple four layers of sand, rock, and cement to create engineering that lasts generations. The planning behind these roads is just as remarkable. Put on a map, it’s visible that Rome is the center stem to almost perfectly straight roads moving in every direction. The Via Appia Antica – a road still used today – is a prime example of Italian construction and history.

Ancient Rome was ahead of her time with transportation. Whether roads were built for the sole purpose of conquering other nations or trading with the east, ancient Rome gave engineers a very tangible object to awe at for generations to come. The construction behind these roads assisted in the fact that we are able to visit them today, whether that’s on foot or driving in a car. The multiple roads stemming out from Rome only assist further in keeping the eternal city one of Italy’s top tourist destinations, and strengthens the idea still that all roads truly do lead to Rome.

References

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