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I'm seeing some conspiracy theories making the rounds which claim that car-manufacturers are intentionally making cars that aren't as fuel efficient as they used to be. They often point to the Geo Metro and claim it got 50 mpg, which is better than even the modern hybrids.

Were cars like the Geo Metro really more fuel efficient than modern cars in the same class, and if so why?

1995 Geo Metro Fuel Economy

2010 Toyota Yaris Fuel Economy

2010 Nissan Sentra Fuel Economy

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    Add a link to the conspiracy claims and info on the Geo Metro showing the 50 MPG. That will make this a great question. – Larian LeQuella Mar 25 '11 at 18:10
  • i added some links for mpg of various cars, but the conspiracy theories are usually in comments on message boards and what not. Probably not that interesting, but an example is the 6th comment down on yakkstr.com/posts/… – jshen Mar 25 '11 at 18:23
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    Those cars are not in the same class. A 1.0 litre engine with manual transmission is likely to have lower fuel consumption than a 1.5 litre engine with automatic transmission and much less than one with a 2.5 litre engine. – Henry Mar 25 '11 at 18:54
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    @jshen, that's the point. Due to modern safety and emissions regulations - it isn't possible to find a comparable vehicle. Look at curb weights and emissions output to find comparisions - not car "classes". – iivel Mar 26 '11 at 2:11
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    Regarding the "same class" / closeness to the Metro points; as a non-US observer, it seems to me that this is specific to the US market. If the fueleconomy.gov site is representative of what's available there, it seems there is no interest in smaller, more economical cars (today / anymore?). This is not intended as any kind of real evidence, but consider this list of economical cars available in Europe. Even boasting more power, they completely outclass the Metro, as expected. – Daniel B Dec 13 '13 at 8:19
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There are a few things at work here:

  1. Safety requirements and standards are much more strict now than they were 10, 15, or 20 years ago. These added components (such as ABS, etc) along with modern luxuries (such as power steering, etc) have added a lot of weight to modern cars. The Geo Metro you reference had a curb weight of just 820kg (about 1800 lbs), while the Yaris has a curb weight of 2311 lbs. That's a difference of 28.3%!

  2. The EPA changed the standard way to estimate fuel economy in 2008. Here is a summary. The standards are now more strict, so I believe every estimate dropped when these went into effect.

Perhaps the fuel economy in general has gone down to make room for better performance as well, but I think that impact is minimal compared to the 2 items above.

Just for fun here is a link suggesting the opposite. They managed to average 48.5 MPG with the 2011 V6 Ford Mustang (this was not an EPA rating, but a test track rating, of course).

http://usnews.rankingsandreviews.com/cars-trucks/daily-news/100625-2011-Ford-Mustang-V6-Nets-48-5-MPG-in-Track-Test/

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    Note that for the Geo Metro example, the displayed value of 40 MPG in the question is using the newer calculation, so I don't think 2. is a factor. – Ken Y-N Dec 13 '13 at 3:20
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    One more reason is a buyers choice. It's possible to make very fuel efficient and even inexpensive car, but nobody going to buy it just because it's going to be very slow and unresponsive. – alex Dec 13 '13 at 23:50
  • @KenY-N - the claim in the question is that the Geo Metro gets 50 mpg; the original EPA rating was 46, and the recalculated EPA rating is 40. So Luke's second point is relevant to the claim, but not to the link. – Mark Dec 14 '13 at 2:13
  • also note that the whole CO2 hype has caused manufacturers to singlemindedly focus on a single emission figure, even to the detriment of fuel efficiency. An engine that needs more fuel but produces less CO2 emissions as a result can lead to subsidies, lowering the sales price and/or increasing margins, as well as allowing you to market the car as "green". E.g. a Honda Insight is less fuel efficient than a Ford Focus Diesel costing the same, but more popular with especially corporate customers because of the "green image" that having your staff drive around in hybrids conveys. – jwenting Dec 14 '13 at 11:51
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    There is only one thing missing to this answer. Since the development of the direct injection engine, increases in efficiency are rather small %. This is a concept that has been developed by a large part of humanity for over 100 years now, so improvements are only left for details. But curb weight exploded in the last decade due to increased safety and comfort features. – Daniel May 3 '18 at 10:05
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There are always outliers, but there is a standard in place for the US called CAFE (and a stricter standard in Europe) which requires the Corporate Average Fleet Economy to meet a minimum. Passenger cars are in a single category, and the standard for 2011 is 30mpg. 1995 was 27. There is a fine which manufacturers must pay if their fleet average falls below this requirement.

see: http://www.nhtsa.gov/cars/rules/cafe/FuelEconUpdates/2003/index.htm

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Another possibile explanation for the perception (not for any statistics on performance) is a general shift in the way people drive. "Hypermilers" intentionally drive in ways that are proven to improve fuel efficiency. (Going slower, planning ahead to use the brakes less, etc)

I don't have any evidence to support this, but my own subjective observation is that in general there seem to be a higher percentage of aggressive drivers today than there were ten years ago. There is a lot of evidence[PDF-FuelEconomy.gov] to support the idea that agressive driving has negative effects on fuel efficiency. "Hypomilers"?

At higher speeds, typical of urban expressway driving, however, the fuel economy penalty of aggressive driving is both significant in magnitude and more consistent across all cars. The average car is likely to experience a penalty of 33 percent, with more powerful cars experiencing a somewhat lower penalty of about 28 percent. Hence the impact of agressive driving seems to be especially large at high speeds.

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protected by Jamiec Dec 12 '13 at 8:05

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