1. Public Transit options (bus, tram, subway, rail) are all available in the USA. Yeah, it "sucks" but there's a bus route for all corners in the USA... and some cities have more advanced options.
2. Public Transport itself can use alternative fuels: Ethanol, Biodiesel, Electric, Hydrogen, Nat Gas. Transitioning a bus from crude oil/diesel into (whatever) will affect dozens, or even hundreds, of people. Especially if we work to fill up our busses for this incoming wave.
3. Some counties / states may not have the resources to transition public transport to alternative-fuels. That is okay, we don't need to reduce all of our oil consumption, just enough to "survive" until the long-term solutions exist.
4. FlexFuel (aka: 85% ethanol fuel), Hybrid, PHEV, and Electric cars exist as individual options. Pushing the standard from E10 (10% Ethanol) to E15 or E20 could very well handle the rest of the impending oil-crisis. All cars built since 2001 are designed to handle at least E15.
5. Carpooling. A car with 5 people in it is basically as efficient as a 30-person bus. If you can't use public transit, create efficiencies by pooling cars together.
Transportation is one of the biggest users of energy consumption in the USA (https://www.eia.gov/totalenergy/data/monthly/pdf/sec2_3.pdf), and IIRC, a significant amount of our transportation-energy is simply cars carrying just a single-person.
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Natural Gas seems more difficult, but in the USA Nat-Gas is basically domestic. This will be a bigger issue for our European friends across the Atlantic.