Yes, there was a conspiracy led by General Motors to replace streetcars with their buses in the 1930s. But streetcars were dying well before then, due to competition with the automobile and other reasons apart from nefarious corporate collusions.
May 12, 2015 Vox
NPR interviews technology historian Peter Norton, D.C. Planning Director Harriet Tregoning, and motorists on D.C. streets who resent exclusive bus lanes, parking tickets, red light cameras, and parklets usurping parking spaces.
Jul 24, 2012 NPR
Sarah Goodyear chronicles the transition of streets in America from public space to the exclusive domain of autos. Professor Peter Norton, author of "Fighting Traffic: Dawn of the Motor Age" explains the ingenuous strategy of the auto industry.
May 2, 2012 The Atlantic Cities