In many ways the transportation problems that seem to be treated as new and suddenly important problems have long histories. Part of those histories is that the solutions being discussed today have also been around a long time (electric cars, hydrogen, more trains and buses).
Here is Jack Nicholson driving around in a 1978 Chevy that's been converted to run on hydrogen. This illustrates that technological solutions are often hampered by political hurdles rather than engineering ones. Had we spent the past 30 years promoting hydrogen, we'd certainly be much farther along in switching to cheap, clean fuel for transportation. Instead, thanks to political decisions that skew the market towards status quo we are grappling with how to move forward now in order to avert a potential crisis. How public policy should encourage innovation and new technological shifts in transportation is a major question that needs much more research.