The enduring image of Roman roads as perfectly straight, arrow-like paths connecting the empire may be a misconception, according to a new study. Researchers analyzing 186,000 miles (300,000 kilometers) of Roman roads across the former empire have created the most detailed map yet, revealing a complex network significantly influenced by local geography and terrain.
Contrary to the long-held belief that Rome served as the central hub and that Romans exclusively favored straight routes, the study indicates that the road network was adapted to the landscape. Lead author Dr. Adam Pazout of the Universitat Autònoma de Barcelona stated that while Roman engineers preferred straight routes where feasible, these roads were generally less linear than modern highways. Mountains, valleys, rivers, and settlements all played a role in shaping their paths, with engineering techniques like terracing, rock cutting, retaining walls, and bridges enabling passage over challenging terrain.
The research utilized a digital model called Itiner–e, which maps the Roman Empire's vast transportation system as it existed approximately 2,000 years ago. This network spanned 1.5 million square miles across Europe, North Africa, and parts of the Middle East. The study analyzed key landscape properties such as average and maximum slope, elevation, and orientation, comparing them with modern paved roads.
Analysis revealed that Roman roads were predominantly straight in flatter regions, but in hillier areas, they tended to deviate more from straight lines than contemporary roads, due to the technological limitations of the era and the obstacles presented by the landscape. The study, published in the journal Nature Communications, identified the least straight Roman roads in mountainous regions of southeastern Europe, while the straightest were found in the lowlands of western Europe and North Africa.
Furthermore, the research suggests that some cities, including Antioch, Ankara, and Byzantium, were more centrally located within the road network than Rome itself. The study emphasizes that Roman roads were more than just transportation routes; they were instrumental in structuring the movement of people, trade, technology, and ideas across the empire. Understanding this network offers new insights into how infrastructure shapes societies and how ancient decisions continue to influence modern landscapes.
To construct the Itiner–e map, researchers compiled data from archaeological and historical records, topographic maps, and satellite imagery. They also used evidence from Roman milestones and remains of ancient service stations. The Roman Empire at its height, around AD 150, encompassed over 55 million people and stretched from modern-day Britain to Egypt and Syria. In Britain, the Roman invasion in AD 43 led to the rapid development of infrastructure, including roads, connecting cities like Londinium (modern London) and Calleva.
Roman roads were typically wide, measuring 16 to 23 feet (five to seven meters), and often slightly elevated in the center. While the Romans aimed for straightness, discoveries, such as a road between Ribchester and Lancaster, show they also considered natural geography to avoid steep inclines. These roads were crucial for efficient goods transport and the movement of soldiers, and many have persisted as the backbone of economic routes to this day.