A few weeks back I talked about a VW Golf that we rented whilst on a trip to the UK. It returned an impressive 88mpg - about 73mpg in US gallons. That's a car you can own and drive today - not some fly-by-night fantasy or future concept. Yes, it's a diesel, yes it has VW's package of fuel economy add-ons (low-resistance tyres, streamlined underbody, stop/start etc) but it's all entirely usable technology right now.
Meanwhile, here in the colonies, we struggle to get 40mpg out of a passenger car and 25mpg out of an SUV is a total miracle. I'm talking about real-world figures here, not the rose-tinted view of the world that the EPA live in where nobody drives in the cold, or up and down hills, or in traffic, or at night, or above 57mph. Heck if you drove that Golf at 57mph with all the electrical items turned off I reckon it would top 80mpg U.S.
I've never really understood why America hasn't taken to diesels. My best guess is that the US-built diesels of the 80's are probably what put most consumers off. Rattly, dirty, noisy beasts that sounded like a 1950's train. But modern diesels are so much better. With the soot and particulate filters and all the other technologies in the engine, they get stellar mpg numbers and in most cases (if you use low-sulphur diesel) are now cleaner than petrol cars for the same engine size. VW knows this - it's why they have the broadest range of diesels of any manufacturer selling cars in the US. Jeep seem to be catching on now - they're going to offer a diesel engine in their range this coming year, but I suspect the old biases will be tough to get past and I don't think diesels will ever really be as popular here as they are in Europe.
The bizarre thing is, of course, that now diesel is so expensive in Europe, people are starting to swing back the other way to hyper efficient petrol-engined cars. Small turbo engines with direct-injection technology are as driveable as any petrol engine you're used to but return diesel-like gas-mileage numbers. Yet again, even with that technology around right now, we still struggle here in the US.
Is it consumer apathy or lack of demand? Is it the low petrol prices? Or is it that vehicle tax over here is still based on the value of the vehicle (in most states) instead of the exhaust emissions? I guarantee if that changed, people would be begging and screaming for properly fuel-efficient engines in their cars....