The streets of Pompeii are and iconic element of the ancient city. Today they are used by tourists exploring the ruins, but they still preserve traces of the traffic that once coursed through this city.

How did Romans drive around an ancient city? If you transported a wagon laden with wine amphorae from a rich man’s country estate to his fancy townhouse, what did you need to know to get there? In a new book, Eric Poehler examines traffic systems at Pompeii, the vehicles and drivers who used those systems, and the people who controlled and maintained them.

No one who visits Pompeii or even spends much time looking at pictures of the ancient city can fail to notice the ruts in the streets. A century and a half ago, the American satirist Mark Twain based his complaints about the corruption of city officials at Pompeii on these cavities:

have I not seen with my own eyes how for two hundred years at least the pavements were not repaired! – how ruts five and even ten inches deep were worn into the thick flagstones by the chariot-wheels of generations of swindled tax-payers? … I wish I knew the name of the last one that held office in Pompeii so that I could give him a blast. I speak with feeling on this subject, because I caught my foot in one of those ruts, and the sadness that came over me when I saw the first poor skeleton, with ashes and lava sticking to it, was tempered by the reflection that may be that party was the Street Commissioner.

Caught in a rut? Such cavities in the street surface can be a menace for modern visitors, but they were gradually worn into the stone by the passage of countless vehicles. This repetition means that the ruts preserve crucial evidence for how traffic moved through Pompeii.

Twain’s passage expresses what each of us naturally intuits: ruts just feel like evidence. Instantly recognisable and immediately understandable, they represent not only ancient people – and lots of them – but also their movement, and create an unconscious link between our act of walking through the ruins and the flow of traffic that once coursed through the living city.

Ruts can tell us much about traffic in Pompeii, including something of its intensity and the sizes of ancient vehicles. What ruts cannot reveal is the actual direction ancient carts were travelling in while producing them. Fortunately, there are more than 600 examples of wear patterns left by carts’ wheels on the kerbstones, crossing stones, and small guard stones in Pompeian streets that do unequivocally demonstrate the direction of travel. Thirteen years ago, I shared the preliminary results of my survey of these patterns in CWA 4 and the final report has now been published as The Traffic Systems of Pompeii. It makes the case for how to recognise these forms of evidence and how to reconstruct the traffic system or systems that produced them. At Pompeii, this reveals the existence of a flexible system that evolved and was altered over the course of a century: there was no single traffic system at Pompeii, but several traffic systems.

Although the wagons using the Roman road system were sophisticated devices, their drivers were reviled for incompetence and coarse manners. As the emperor Vespasian discovered, even at the top of the imperial hierarchy the mark of the muleteer never truly washed off.

Wagons roll

To appreciate how traffic flowed through the city a number of new areas needed to be explored. For example, who were the people driving in Pompeii and what did their vehicles look like? Unlike today, when most people are using their own vehicles for their own purposes, in the Roman world, most drivers were slaves or former slaves. These people were looked down on (at least in literature) more for their poor character than their lowly status, and were accused of using loud and coarse language, being unclean, and even dangerously incompetent when driving or packing their vehicles. Not even the Emperor Vespasian, who once owned a mule-driving business, could escape the taint of that association, and was chided for his rustic pronunciation of the Latin word for wagon (plostrum, rather than plaustrum).

However one pronounces the name of these wagons, they have been underexamined and underappreciated by modern scholars. Whether they were a lighter, two-wheeled cart called a cisium or birota, or a larger four-wheeled wagon called a plaustrum or raeda, these vehicles were remarkable examples of ancient technology. A wagon from the villa Arianna at Stabia, buried during the eruption of Vesuvius in AD 79, showed each wheel was fitted with an iron tyre 117cm in diameter and 3.5cm wide. This diameter equates to almost exactly four Roman feet, precisely the size recommended by the ancient architect Vitruvius, because it allowed a kind of odometer to be fitted. This used the number of wheel rotations to keep track of the distance travelled, although no such device was found at Stabia.

The remains of the four-wheeled wagon discovered at the villa Arianna at Stabia. This vehicle had the capability to dodge obstacles without change course, and even – if an odometer had been fitted – keep track of the distance travelled.

An equal level of complexity can be seen in the steering system. The pole linking the vehicle to the animals providing the means of propulsion was connected to the front axle. It could pivot independently by using two curving wooden forks that slide into notches in the framework just above the axle. This design permitted 20° of sway for the draft animals to avoid objects in the road before force was applied to the axle, causing the entire vehicle to change direction. When this occurred, an iron bar that bound the forks together was engaged against the axle. This bar turned both wheels until they came into contact with the body of the cart, where iron plates were attached to prevent damage to the frame. It gave the wagon approximately another 12° of motion.

Stepping stones for pedestrians to cross the streets without having to set foot on them are a common feature of Pompeii. It boasts 20 times more crossing stones than are known at any other Roman city, a provision that may speak volumes about the quantity and quality of water draining through Pompeii’s streets.

Such mechanisms were essential at Pompeii, because the streets were narrow (80% were limited to a single lane), the kerbs were high (more than 30cm on average), and crossing stones in the middle of the street were especially abundant (316 of them, 20 times more than are known at any other Roman city). This street design was necessary to contain the constant overflow of aqueduct water from three dozen public fountains and the runoff from rainstorms, since Pompeii lacked proper under-street sewerage. The expectation for so much water in the street, together with the sloping terrain of the city, meant that Twain’s vision of a rubbish-filled roadway was mostly, but not entirely, wrong. Recent excavations revealed a street that seems to have been orphaned from the overall network. This street was partially blocked at its intersection with the main thoroughfare and strewn with construction debris and the detritus of daily life: dirt, bones, and broken dishes and pots.

All images: Eric Poehler

This is an extract from the full article in featured in issue 87 of Current World ArchaeologyClick here for more information about subscribing to the magazine.

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