Our diesels typically don't get twice the fuel mileage as their gas counterparts. The other thing you have to figure in is the cost difference between buying a gas car vs diesel as a diesel engine option usually fetches a few thousand more than the same vehicle with a gas engine. Unless you buy used, drive many many miles, or really want a diesel, in many cases your better off buying a fuel efficient gas vehicle over here because it will take a long time to realize some savings.

Many diesels in the US will cost less over a 3 or 5 year than their gas counter part in TCO. Yes, they cost more to buy, but they will recoup most of that extra cost on resale or trade in. Or fuel costs if driven far and/or long. The EPA TCO numbers are further helped by the fact that diesels tend to do better than EPA more often than gasolines.

The issue in the US market is that we have a small selection of diesels, and many that we do get are a larger displacement than available in Europe. The smallest size we have is 2.0L. When the Cruze Eco with the 1.4T gets nearly the same EPA rating as the Cruze diesel, the diesel isn't going to do as well. GM does have smaller diesels in the Cruze overseas though. The savings become obvious when the engine is like vs like, as in the the BMW 328d and 328i. Which is the other issue with diesel cars for the US. Most are in expensive luxury brands.

Diesel trucks are an easier sell. The can haul more than the fuel efficient gas version, and get much better fuel economy than the gas of equivalent payload. People don't tow with cars in the US. That, and stricter tow rating standards, means that cars no longer have a tow rating. Older VW TDI Jetta wagons were rated for a ton, but nothing is published for the current model.

Thats because US marketed cars are engineered lazy too, a lot still use the very dated torque converting autos (which I hate!) and typically have 5 or 6 gears. European cars use double clutch boxes which are much quicker at changing gear, are lighter and can have anywhere between 8 and 12 gears keeping the revs lower when cruising. On saying that, a good 80% of cars here are manual thankfully, which are instantly around 25% more efficient than an auto to begin with. And also, strict carbon emission standards have had auto makers fine tune engines these days for efficientcy as well as performance. The 3.0 diesel found in the new BMW 5 series does 0-60 in 4.8 seconds and still does close to 60 MPG too. Best of both.

It is difficult to make direct comparisons, because it is rare for exactly comparable vehicles to be available with gas or diesel options. From what I have seen, it is usual for a diesel to make 30% to (maybe)50% better mileage. The diesel engine option is usually considerably more expensive, too. These comparisons do not use government tests, but actual real driver use. For instance, Consumer Reports gives the gas mileage of the Chevrolet Cruze as 26; the turbo diesel as 33. They have commented that the diesels of today are not the same as the noisy, smelly, and smoky diesels of the past.

My own experience with a diesel was a Renault-based Winnebago LeSharo. It had a 2.0 liter turbo diesel, said by its service manual to produce 75 BHP. It got about 17 mpg. When I had some work done by Winnebago Industries, I had a good chance to talk to the techs. They told me the 2.0 turbo diesel (manual transmission) and the 2.0 liter gas (with auto transmission) got almost exactly the same mileage, about 17. That doesn't seem to me to show diesels getting twice the mileage.

The post is about gas prices btw. We're down under 3$ here in east central IL at some stations. Toward the middle of the state they're around $2.80. I expect them to go lower. That is a real savings for me driving about 80 miles per day. Gasbuddy shows Missouri with the lowest average prices and several stations below $2.50.

Kevin

I think all your data, 1 vehicle, from about 20 years ago, which isnt even a car is a little outdated Charon! I could show you at least 100 cars that get double the mileage of thier gas equivelents. Take a V8 for example, Audi V8 TDI gets 40+ MPG, whereas a gas V8 you're probably looking at 20's MPG. Another thing to condider is that in the UK diesels are cheaper to insure, my new car despite being bigger, with a larger engine and being worth twice as much as my old car, is around $750 a year LESS to insure, so the extra cost is soon made worth while.

2011 Golf TDI (40.8 mpg)
2014 Mini Hardtop 3 cyl (40.5 mpg)
The mini uses premium that cost a bit more than diesel in the summer, but diesel cost a bit more in the winter. There was no mpg advantage either way between these two vehicles. TDI had more torque yet the Mini felt faster.

The Golf TDI is rated at 94 MPG here, and the mini just 56 MPG. Sure I know the tests always feature hard to acheive figures in the real world, but there's stil a huge difference. The only gas engines that come close to diesel economy are all tiny turbocharged units, which end up being less economical as you tend to work them and rev them harder, just the nature of the engines.

Sorry for going off topic, it always does! Well I just fuelled up and it seems our fuel has dropped a little amazingly! Just paid $10.02 a UK gallon (just over $8 for a US gallon) could be better, could be worse.

I never said the data was current - I said it was my own experience. And the unit was sold as an '84, on a Renault '83 chassis, so it is actually a 30-year old unit. The LeSharo was based on a Renault Trafic. It did indeed fulfill its design object of getting about twice the mileage of conventional motor homes, although at the price of being painfully underpowered. It worked during the late lamented days of the USA 55 mph speed limit, the same general era of the also dreadfully underpowered VW Diesel bunny.