Even if every car on the road was powered by corn oil, cars (and SUVs) would still be cutting us off, dooring us, running us over, recklessly accelerating, clogging up city streets (in motion and while parked), consuming tons of nonrenewable resources in their construction, fostering the continued growth of suburban sprawl, shutting people off from each other and from fresh air, leaking nasty fluids into parking lots, and in general making life miserable. That's why the only 'clean' car is... a bike.