Why Ancient Roman Roads Still Affect Modern Economies Today
Don’t underestimate the power of habit over time
“The default carries immense power even in advanced industries like rocket science. This idea is called path dependence. What we’ve done before, shapes what will come next.”
— Ozan Varol, Think Like A Rocket Scientist
In certain ways, we’re all creatures of habit. There’s a comfort in a routine, especially if it works and gives your mind a break from the stress of decision making. But it goes beyond the individual.
Nations, organizations, and even NASA cling to habit. A former employee, Ozan Varol, in his book above mentions the engines on NASA’s rockets are four foot, eight inches wide for the strangest reason. Mainly, to fit a rail line from Utah to Florida.
Although that’s just where it starts. The rail line is that width because it’s built according to similar specs from rail lines in England. Why are English lines that wide? They’re based on ancient Roman roads.
So, the modern rocket engine is the ultimate creature of a habit that’s existed for two thousand years. However, it’s only one example. At the peak of its empire, Rome had about fifty thousand miles of roads.
These roads were so plentiful and well built, their remnants can be seen from space.
What’s more, a group of economists from Denmark claim that within Europe “Roman roads not only predict current infrastructure, but also ancient and current economic activity.” Talk about the power of habit.
Now, the rocket connection is somewhat obvious, but how can modern infrastructure and economics be connected back to ancient roads? Easy. Just follow the lights.
Lights Observed From Space Along Old Roadways
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In 2018, four economists from The Centre for Economic Policy Research took a map of Roman roads at the extent of their empire in 117AD and compared it with modern data. This included “nightlight intensity,” or a map of lights at night taken from space, along with population density.
Just by eyeballing the maps overlaid on top of each other, they noticed a connection between the light distribution and the amount of Roman roads within an area. According to the team:
“From a bird’s-eye view, there does seem to be a (reduced-form) link between the location of ancient roads, and economic activity today.”
To confirm their suspicions, they performed a regression analysis. The economists found that areas in Europe with high road density today, had similar densities in Roman times. Plus, there was correlation between nightlights and Roman road concentration.
Both had a ninety-five percent confidence interval. Although they noticed this didn’t hold true with parts of the Roman Empire in North Africa and the Middle East.
In many ways this made sense. The team notes that this section of the world didn’t make much use of wheeled carts “during the second half of the first millennium.” Camel caravans supplanted them due to technology and terrain.
Better saddles and skilled riders with improved weapons made camels “the dominant mode of inland transport” within these areas. Not to mention flexibility and endurance of both the animal and their rider.
T.E. Lawrence (Lawrence of Arabia) found camels could go about two hundred fifty miles without water and march a hundred or so a day while carrying six hundred pounds. In his book Seven Pillars of Wisdom, he mentions each of his camels could carry six weeks of supplies too.
With animals like these, who needs carts? And if carts aren’t needed, what’s the point of putting resources into roads?
The team found this habit carried into modern times, with little correlation between Roman road density and development today in North African and Middle Eastern regions.
But for the regions where there is a connection, what makes a Roman road so special?
Roads Worthy Of Rome
Miles of modern highways are built and paved quickly, only to break apart and need continued resurfacing every year. However, Roman roads were built to last. They were projects built upon layer after layer of material.
According to the documentary Roman Engineering: Roads, The Neural Network of the Empire, Roman engineers first cleared all the vegetation and top soil, looking for a “solid base.” Then, curbs were placed and the opening filled with large rocks. Smaller stones and material covered this. Finally, gravel, sand, and clay made a top layer.
This final layer was spread evenly, watered, and packed down with cart-drawn rollers. After, the edges were tipped down to direct rainwater away.
Once the road was complete, ditches were dug parallel to it twenty meters on each side.
These gave the traveler a line of site to notice danger, and kept unauthorized carts from the road.
While the famous Appian Way, and Roman roads within cities were topped with flagstone, most weren’t. This stone could be slippery. It was designed to repel mud and be easier to clean. Traditional Roman roads had a gravel cover, which was perfect for cart-drawn traffic.
These roads connected the empire like veins within a body, and their shadows are still present today.
Roman Infrastructure And Modern Europe
This research on Roman roads says a lot, and in certain ways, not much at all. First, it states the obvious. Infrastructure can help communities and regions develop commerce.
Furthermore, once you have a settled region with a large population and diverse center of commerce to support them, it makes sense to keep it going. Consequently, some populated areas continue this way for thousands of years.
However, this study also shows the sophistication in Roman engineering throughout their empire. Roads weren’t just an afterthought. They were a type of glue which connected first the republic, then empire together.
They weren’t the flagstone we often imagine (well, except for cities), but levels of crushed rock, stone, and fillers. Hence, they were perfect for carts. Furthermore, they were designed to last for years, with some still visible today.
What’s more, current population centers within Europe follow the paths of these roads. And their nightlights form a map. They shine up to space as modern milestone markers for the highways of the ancient empire.
After all, there is a certain comfort in routine. Perhaps that’s why ancient Roman roads still affect modern economies today.
-Originally posted on Medium 5/18/23