Study finds ancient Roman roads were more winding than believed

A new study has overturned the widespread belief that ancient Roman roads were built as straight as lines, ERR reports. The roads were generally straighter where the terrain allowed, but modern highways are considerably less winding.

An international research team from universities in Denmark, Spain and several other countries created the most detailed digital model yet of the Roman Empire’s road network. Their computer analysis covered nearly 300,000 kilometres of ancient roads and examined their gradients, direction and curvature.

The roads’ design was shaped by the transport of the time and practical needs. Goods were mainly carried by animals and heavy carts, so gradients could not be too steep. More than 90 percent of the empire’s roads had gradients of no more than nine degrees, the study found.

The Alps provide a particularly striking example. Despite the high mountains, Roman engineers kept road gradients lower than in many other mountain ranges. They built terraces on slopes and cut roads into cliffs to maintain connections between Italy and the rest of Europe. In more difficult terrain, they preferred switchbacks and routes through valleys to straight lines, allowing smoother travel.

The study also found that Roman infrastructure continues to influence Europeans indirectly. Many major roads today, particularly in Western Europe, still follow the routes of former Roman roads. Some ancient settlements also grew into major cities such as Paris and Madrid, although the road networks around them have changed considerably.

Modern roads are straighter because machinery and extensive earthworks make it possible to remove obstacles with bulldozers. Ancient roads had to adapt to the surrounding landscape. The provincial capitals of the Roman Empire were also located along the network’s main routes and functioned as transport hubs.

The researchers published their analysis in the journal Nature Communications.