Can you picture a world where California banned the internal combustion engine by 1975? In 1967 California State Senator Nichoals C. Petris introduced SB 1291 which proposed just that:
Notwithstanding any other provision of this chapter, on or after January 1, 1975, no motor vehicle powered by an internal combustion engine shall be operated on the highways of the state.
It's simple and bold language was a response to California's statewide smog problem, as reflected by the creation of the California Air Resources Board in 1967 to tackle the issue. SB 1291 didn't make it out of the assembly, though it did scare auto makers into action. Petris continued to confront the role of personal automobiles and the internal combustion engine in the state's air pollution, working with groups like Stamp-Out-Smog, and enlisting the support of "consumer crusader" Ralph Nader.
California began leading the way on pressuring the car companies in cleaning up tailpipe emissions which culminated in the Clean Air Act of 1970. 50 years later California is still setting an aggressive agenda in combatting air pollution, most recently with SB32: California Global Warming Solutions Act of 2006.