Before I get to the main subject, I'd really like to see two of SmartPlanet's writers weigh in on this article as commenters, not necessarily as contributors: Christina Sherwood, the author of this article, and Tyler Falk, who writes about cities for SmartPlanet.
When I was growing up in the Philadelphia metropolitan area, my city had trolley buses--or "trackless trolleys"--until I was seven or eight. They were clean and quiet, but they were useless if a traffic accident necessitated a detour or a street needed to be closed for maintenance. Hence the switch to buses in the late 1950s (see
http://oldwilmington.net/oldwilmington/transportation_1.htm).
Now to address the GM issue. The companies accused of conspiracy were: GM, which manufactured the buses; Firestone, which manufactured the tires; and Standard Oil, which provided the fuel. The Bradford Snell report to Congress (1974), which detailed the conspiracy, is presented in Stanley Fischler's book, "Moving Millions: an Inside Look at Mass Transit" (Harper & Row, 1979). Fischler states that Alfred Sloan, in order to increase GM's automobile sales, bought out and closed streetcar companies, changing to what he called "inferior bus service", and that inferior service caused former transit customers to buy their own cars. That, in a nutshell, is the conspiracy story.
I'll offer some sources in my next comment.
