The transport system of the Roman Empire reflected the geographical characteristics and constraints of the Mediterranean basin. The Mediterranean Sea played a central role in supporting trade among a network of coastal cities, the most important of which were the Empire’s (Rome, Constantinople, Alexandria, Carthage, etc.). These cities were served by a maritime and road network that permitted trade within their respective hinterlands. Little fluvial transport took place because the major pan-European rivers, the Rhine and the Danube, were military frontiers rather than the core of the empire.
The road served numerous functions, such as military movements, political control, and cultural and economic (trade). Road management and maintenance fell into four categories: via publica (main public roads crossing provinces), via militaris (maintained for military purposes), via vicinalis (provincial roads connecting towns to main roads), and via privata (managed by private landowners but open to the public). To improve travel speed, posthouses with fresh horses were spaced every 15 kilometers along the route, and lodgings for travelers were available about every 40 kilometers. This 40 km corresponded to the average distance a traveler could cross each day. Courier services could travel twice that daily distance. Since maritime transport was more efficient than road transport, it was less costly to ship grain from Egypt to Rome than to transport grain from other nearby areas of Italy to Rome by road. The notable exceptions were the Nile and the Rhone rivers.
The Appian Way (Via Appia), about 560 kilometers in length, was one of the first Roman roads (Via) to be constructed (around 312 BC) under the initiative of consul Appius Claudius Caecus. It linked Rome to Brundisium (Brindisi). As the empire grew, this system was expanded to cover 80,000 kilometers of first-class roads at the height of the Roman Empire (around 200 AD). Most of the roads were constructed by soldiers, prisoners of war, and slaves. The minimum requirements for a first-class road were a width of 5 meters and a drained stone surface. The Romans also built the world’s first dual carriageway, the Via Portuensis, between Rome and its port, Ostia, at the mouth of the Tiber.
The Roman Road network covered most of the conquered provinces, with Rome as the focal point (thus the saying “All roads lead to Rome”). At the center of Rome was located the milliareum aureum (the golden milestone), from which the Roman roads radiated. Way stations where travelers could rest and eat dotted the network. The system collapsed during the Middle Ages due to neglect and the plundering of construction materials. However, the remains of the Roman network provided transportation in Europe for a thousand years. Only small segments of this system are left today.