Where Are the Oldest Roads in the World?
The earliest known constructed roads date back to ancient Mesopotamia, in present-day Iraq. These stone-paved streets were built around 4000 B.C. in the cities of Ur and Babylon. Located in the fertile lands of the Sumerians, these roads enabled efficient irrigation, farming, and livestock management, supporting the growth of early civilizations.
The Sumerians were skilled brickmakers, creating uniform mud bricks that were dried and transported to temple sites, then bonded with bitumen, a naturally sticky black substance found in asphalt. Asphalt would not appear in Europe and America for many centuries.
In Glastonbury, the legendary Isle of Avalon in Somerset, England, archaeologists discovered timber roads built in swampy areas. Glastonbury, famous for King Arthur legends and home to Glastonbury Abbey, attracted pilgrims for centuries. These early roads enabled carts and wagons to travel more easily, although more advanced roads would come later.
An interesting figure in early road construction was John Metcalfe, a Scottish man born in 1717 who was blinded at age six. He built miles of roads and bridges in Yorkshire, England, using a three-layer system: large stones, a mixed road base, and a gravel topping.
Two other notable Scottish engineers, Thomas Telford and John Loudon McAdam, are credited with creating modern road-building techniques. They introduced cambered roads to improve drainage. Telford also analyzed stone thickness, traffic volume, alignment, and slopes, pioneering methods that became standard practice. His achievements include numerous bridges, canals, harbors, and the renowned Menai Suspension Bridge in North Wales, completed in 1826.
McAdam, born in 1756, developed roads with a hard, durable surface, layering broken stones in tight, orderly patterns and covering them with smaller stones. His system, called “Macadam”, revolutionized 19th-century road construction and eventually evolved into tarmacadam, the bitumen-bound roads we know today. The first tarmac road in Europe was built in Paris, with the Champs-Elysees being covered in asphalt in 1824. By the late 1800s, the United States began paving roads, including Pennsylvania Avenue in Washington D.C.
Today, most roads in the U.S. are paved with asphalt concrete, a mixture of asphalt binder, sand, and crushed rock. Despite its simple appearance, modern asphalt is a highly engineered material. According to Bob McQuiston, FHWA Pavement and Materials Engineer, asphalt must be carefully designed for durability, stability, and resistance to heavy traffic. Modern pavements often include polymer-modified binders to prevent rutting and fatigue, while remaining flexible enough in cold weather to avoid cracking.
The aggregates used—both fine and coarse—are crushed to precise shapes and sizes to enhance stability and support heavy trucks. Contemporary pavements can be engineered for long-lasting durability, better skid resistance, and a smoother ride, meeting the demands of modern highways. Whether building new roads or maintaining existing ones, asphalt remains essential to keeping the transportation network safe and efficient.