I am a car fan. I am not, however, a fan of gasoline (petrol) or diesel fuel. My point is that most of the environmental concerns around automobiles arise from their nearly obligate use of fossil fuels, not from automobiles themselves. Biodiesel is an option, and can be refined into lighter fuels.

Such fuels would at least give carbon-neutral options to people who are stuck with whatever car they have right now, with no special modifications or adjustments needed. Even if you like sports cars I got news for you. Ethanol is higher octane than the best gasoline you can get. That = more power.