The urban freeway

What it is

The urban freeway is a high-speed, grade-separated motorway driven directly through the built fabric of a city, developed from German autobahn engineering of the 1930s and built at huge scale in the United States after the 1956 Interstate Highway Act. Routes were often pushed through poorer and minority neighbourhoods, where land was cheap and political resistance weaker, severing street grids and displacing residents. Elevated decks and trenches cut neighbourhoods off from one another.

Why it matters

Urban freeways reshaped, and frequently gutted, mid-20th-century cities, enabling car commuting while hollowing out the districts they crossed. The damage they caused has driven a growing movement to tear them down and reconnect the surrounding streets.

Plans it shaped

• Regional Plan of New York & Its Environs (1929)
• São Paulo Plano de Avenidas (1930s)
• Plan Obus for Algiers (unbuilt) (1931–1934)
• Islamabad (1960)
• Curitiba Master Plan (1966)
• Milton Keynes (1967)
• Second Regional Plan for New York (1968)
• Tehran Master Plan (1968)
• Greater Cairo Master Scheme (1970s)
• Karachi Development Plan 2000 (1973–2000)
• Mexico City Plan Director (1976)
• Barcelona 1992 Olympic Plan (1986–1992)