From What is the Future? by John Urry, loc 2554-2570:

This car-based suburbanization is neither natural nor inevitable, and in the US partly stems from a ‘conspiracy’. Between 1927 and 1955, General Motors, Mack Manufacturing (trucks), Standard Oil (now Exxon), Philips Petroleum, Firestone Tire & Rubber and Greyhound Lines conspired to share information, investments and ‘activities’ to eliminate streetcars from American cities. They established various front companies, especially National City Lines, which during the 1930s bought up and then promptly closed at least forty-five electrified streetcar systems (Urry 2013b: ch. 5). These cities lost their streetcars and came to depend upon petrol-based cars, trucks and buses for moving about.