Well, here in the south it doesn't really make a big difference compared to gas. Most of the time I pay around 1.50 dollars per gallon. But back in the Netherlands there is a huge difference. When I left, it was like 4.30 euros (...5.18 dollars) per gallon for euro 95 gasoline and about 2.80 euros (3.35 dollars) for a gallon of diesel. Diesel is cheaper because there is less tax on it (otherwise roadtransport would be a not-so-profiting sector of business -trucks drive on diesel). The reason why the whole country doesn't drive diesel cars is that the government lets you pay more tax on your annual car tax and an extra tax of approx. 1500 euros on a new car price (although my car emits less carbondioxide, it does emit more sh*t like sulphur). So do the math and you know that you need at least 10.000 miles per year to make a diesel car more economical for your wallet. And I drive way more than that most of the time.