Controlled-access highway

The controlled-access highway emerged because an Italian engineer recognized that automobiles needed roads designed specifically for them—roads where horses, pedestrians, and intersections would not impede the machine age.

On September 21, 1924, the Autostrada A8 opened between Milan and Varese in northern Italy—approximately 50 kilometers of road designed exclusively for automobiles. Civil engineer Piero Puricelli had conceived and championed the project. His innovation was not just better pavement but a new philosophy: cars would enter only at designated points, and nothing else would share the road.

This was revolutionary. Every road in history had been designed for mixed traffic—pedestrians, animal carts, bicycles, and eventually automobiles all negotiating the same space. Puricelli proposed segregation. The autostrada would serve only motor vehicles, with controlled access points (what Americans would later call on-ramps and off-ramps) replacing the crossroads that interrupted traffic flow.

The word 'autostrada' combined 'auto' (automobile) and 'strada' (road), creating a naming convention that would influence German ('Autobahn'), Portuguese ('autoestrada'), and Spanish ('autopista'). Italy expanded the autostrada network through the 1920s and 1930s, building a demonstration of what high-speed motor travel could achieve.

Adolf Hitler visited Italy and reportedly admired the autostrada system. Germany began constructing its Autobahn network in 1933, drawing explicitly on Italian precedents. The United States would not build comparable highways until the Interstate Highway System began in 1956, more than three decades after Puricelli's Milan-Varese road.

The controlled-access highway transformed more than transportation. It reshaped cities, enabled suburbs, changed where people lived and worked, and—through the Interstate Highway System—became the largest public works project in American history. Every freeway, expressway, and interstate descends from Puricelli's insight that the automobile deserved its own infrastructure.