Hopefully every 20 yrs or so, the average time from ambulatory houseplant to sentience for a human, people will see personal vehicle ownership in population centers, as less and less necessary, already many young people have little interest in cars/driving, but this will take lots of time, and in this vast country, public transportation is not practical, I know people who drive a half hour each way just to a good grocery store or Wal-Mart/Target, no bus service, no trains, what are they to do? I have commuted on 2 wheels for much of my working life, not to be green but because I enjoy riding, but we do not all live in sunny So-Cal, there is this winter thing where no 2 wheeler makes sense, I have used the bus service, purposely got a place on a bus line, but my current job would only allow me to go in to work, service stops before my shift ends, so I drive, a small fuel efficient car vs my big tank or my truck, if I did not car-pool my boss home I would go from using aprox 2 gallons of fuel a week to using 1 gallon a month on my moped, but again, winter? The trick to being green is not hybrid tech or electric bikes, though all have a place, but to waste less, buy local, buy used vs new all the time, our mopeds are 40 odd yrs old but still in use, how many 40 yo cars are still used? The poorest among us live like kings compared to prob half the world, "know" this, conserve, think, turn off lights, conserve water, walk or bike vs driving, moped, when it is feasible, we are spoiled in the United States, being born here is an accident of geography, embrace it, don't waste it. I do these things, partially because I'm not wealthy, and partially because I see so much thrown away, that is perfectly serviceable, for every un-repaired anything a new one must be produced, and the old one has to go somewhere. If we don't shape up as a species, the planet will deal with us, as it has so many others, going more sustainable is not going to save the earth, it will save us, from ourselves.