I saw this on a rerun of that terrific PBS series, The History Detectives. It comes from 2006, their Season 4, episode 10. From this link you can download the transcript of the story with one click.
http://www.pbs.org/opb/historydetective ... c_car.html
It turns out that in the 1930s and 40s, General Motors, Firestone Tires, and Standard Oil conspired to replace the very popular clean-running electric trolley system in this country (which you may recall from certain very old movies) with buses. These would be GM buses, running on Firestone Tires, burning Standard Oil. Incredibly, these giant corporations were able to destroy a system of mass transit that was well established nationwide, and very popular at the time they went to work on it. It makes you wonder how many other stories like this are out there. You should read the entire transcript. Here's a little bit of it -
Wes: Black says once they understood the local system, GM and its partners would fund the purchase of the streetcar line. Now, was all of this done with sort of a handshake and a pat on the back, or were there actual contracts?
Edwin: Oh, yes, there were ironclad contracts. These companies would insist that only their products would be used, only their buses would be used, and of course that the trolley systems would be dismantled, destroyed, and quickly converted. And that is how our mass transit was converted from clean electric trolleys that people loved, to these-- these smoke-belching, petroleum-addictive motor buses.
Wes: GM was convicted of monopolizing bus sales, but Black believes they had a bigger agenda. What they desired was the takeover of the entire national transit system. They had created a whole new mind-set, and ultimately, the momentum that they had put in motion subverted the entire trolley system.