But that logic doesn’t account for a different phenomenon: On the whole, clean-diesel sales have leaped by 124 percent compared with last year; that’s a serious improvement, and if both trends continue, then hybrid and diesel sales will be dead even in as few as five months. So why are diesel models growing in popularity in a market that has traditionally shunned diesel as an alternative fuel? There's no magic answer, but several factors are likely at play.

For starters, a few very desirable diesel models have hit the market in the States, giving American buyers a small taste of what European consumers have been enjoying for years. Cars like the Jetta TDI and Jetta SportWagen TDI have proved that excellent fuel economy need not require sacrifices in comfort and power, nor does it always mean a large price tag. Similarly, BMW, Mercedes-Benz and Audi are all enjoying growing diesel sales in the US.

There’s also the fact that diesel technology has advanced by leaps and bounds in America. Diesel engines are quieter and cleaner than ever, all while offering fuel economy well above 40 mpg in some models. The times, they are a-changin' -- at this point, it’s just a matter of whether manufacturers are keen enough to realize American tastes are changing with them.