(Courtesy Eric Poehler)
As a student excavating in Pompeii, archaeologist Eric Poehler made the unusual choice to study the ancient city's traffic patterns. Now an adjunct professor of anthropology and classics at the University of Massachusetts Amherst, he spoke with ARCHAEOLOGY's Eric A. Powell about one-way streets in Pompeii, bumping against curbs, and how the Romans managed without stop signs.
How does traffic show up in the archaeological record? It seems like a fleeting phenomenon that wouldn't leave any evidence.
The most obvious features in Pompeii are wheel ruts left in the paving stones. You can easily imagine the thousands of vehicles that made them. The ruts tell us there was heavy traffic, but not much about how it was organized.
How can you reconstruct traffic?
On the curb stones there are patterns of wear left by wheels that can tell you in which direction vehicles were headed. Because roads were used for water management, vehicles also left wheel wear on blockage stones that controlled the flow of water. There are also marks on the stepping stones pedestrians used to cross flooded streets.
Why is it important to know the direction of traffic?
At first I thought I'd find only a few streets that were consistently one-way. But what I discovered was that even the back streets had evidence for one-way traffic. That tells us street traffic was a city-wide system planned at the highest levels of the city administration.
Can you distinguish between the marks left by, say, an ox cart and those made by a chariot?
Well, nobody was rolling around in a chariot unless they were in the circus. Personal transportation as we understand it today wasn't very common. The kind of vehicles we're talking about are two- and four-wheeled carts used for things like carrying goods or hauling trash. In the first century a.d. they had iron rims, which created these distinct wear patterns. In some instances you can still see iron stains in the marks on the curbstones.
I assume that drivers would want to avoid hitting those stones. So in a sense, are the marks also evidence of bad driving?
No, I think of it as evidence of a small city gone big. The streets were very narrow, I'd say there were about 100 streets, and of those more than 80 percent were one lane. It was the narrowness of these roads that was responsible for this wearing pattern.
So even the very best cart drivers probably left these marks.
You know, everybody runs over a curb once in a while. Imagine if you were driving your car and you had fewer than 18 inches of clearance on either side. You'd probably hit the curb fairly regularly too.
Sounds like driving wasn't much fun--probably even a little terrifying--having to navigate
the narrow one-way streets.
You're right. Traffic catastrophes were so common that Roman case law used examples of accidents in discussions of larger legal concepts; liability, for instance, like who's responsible if a slave crashes a cart into someone. Driving could be dangerous. That's one reason a traffic system had to be put in place.
How did the government enforce the system?
They didn't have stop signs or one-way signs. So while it's clear traffic flow was designed by the city administration, it was actually run by the people who were involved in it--the drivers. It was their cooperation that actually kept the system going.
Has studying traffic had any impact on your own driving?
Absolutely. Now when I drive, I pay a lot of attention to the infrastructure surrounding traffic. For instance, we still use curbs and concrete barriers to tell drivers to stay away from sidewalks and buildings. That's a technology that hasn't needed improvement in the last 2,000 years.
But you don't think your driving habits have changed?
I actually don't see modern driving as directly analogous to ancient driving. In Pompeii the traffic was organized to prevent gridlock, but today it's organized around vehicles maintaining incredibly high speeds Roman drivers couldn't even begin to imagine.