Diesels get good gas mileage
but are very heavily polluting (The VW TDIs are the worst polluting vehicles on the market in their classes) if using the diesel fuel that is available in North America.
In Europe they have low-sulphur fuels which I've heard are much better in this regard (Low sulphur means less sulphur compounds in the tailpipe which means less acid rain). You'll also hear a lot of people nattering about bio-diesel, which if I remember correctly is made from corn and burns relatively cleanly but isn't yet available at the pumps anywhere in the world.
Originally posted by Slow-N-Low
Why don't you see more diesel cars in N. America? Take a look at Diesel prices. A gallon of Diesel costs more than a gallon of gas, and contains less energy.
I've never seen diesel cost more than 87 octane unleaded.