July 19, 2006
Car Fuel Efficiency Gains Used For Speed And Size

Technological gains that in theory could increase vehicle fuel efficiency instead get used to make cars bigger and faster at the same average level of fuel efficiency.

The Environmental Protection Agency said in its annual report, based on sales projections provided by automakers, that the estimated average fuel economy for 2006 vehicles was 21 miles per gallon, the same as 2005 models.

Since they are using sales projections they are weighting for number of units sold. High oil prices? Expensive gasoline? Yes, but faster acceleration is just so much fun.

Even as Toyota ramps up hybrids production it is ramping up bigger cars even faster for a net loss in fuel efficiency per mile travelled.

Honda Motor Co. had the highest fuel economy rating by manufacturer, 24.2 mpg, followed by Toyota Motor Corp., with a 23.8 mpg average. But both Japanese automakers saw their averages drop from the previous year as they placed more of an emphasis on larger vehicles.

6 speed transmissions, engines that turn off some cylinders while cruising, hybrids, new lighter materials, and other innovations plus the big rise in oil prices were not enough to change the average fuel economy of new cars. Attempts to increase efficiency get undermined in at least 3 ways by consumers:

  • People choose bigger cars and SUVs.
  • People choose models that accelerate more rapidly.
  • People drive more miles.

Most of the increases in wealth due to productivity increases are going to those who already earn higher incomes. The gaps between the classes are widening. Upper class folks are less affected by higher gasoline prices. At the same time, they buy a disproportionate fraction of all new cars. So new car buying patterns haven't shifted as much in response to higher oil prices as you might expect. Lower class folks tend to buy used cars. So the fuel economy of used cars is lowered by the upper class folks who buy new cars.

Auto pricing changes also have reduced buyer responses to higher fuel costs. The auto makers have higher profit margins on larger vehicles. They've partially compensated for higher gasoline prices by lowering prices more on less efficient large vehicles. So the buyers effectively haven't seen as large an increase in total vehicle ownership costs as you might think if you look at gasoline price increases alone.

Fuel economy has changed little since 1992 even though automotive technology has advanced.

Since 1992, average real-world fuel economy has been relatively constant, ranging from 20.6 to 21.4 mpg. This 21.0 mpg value is five percent lower than the fleet-average fuel economy peak value of 22.1 mpg achieved in 1987-1988. For model year 2006, cars and light trucks are each projected to account for about 50 percent of vehicle sales. After two decades of steady growth, the light truck market share has been relatively stable for five years. New technologies have maintained fuel economy while supporting the heaviest and fastest new vehicle fleet since EPA began compiling data in 1975. Recent technology developments, such as hybrid-electric vehicles, clean diesel technology, improved transmission designs, and engines equipped with variable valve timing and cylinder deactivation, hold promise for stable or improving fuel economy in the future.

There's also a type of higher efficiency gasoline engine under development that uses compression for ignition like diesel does. The gasoline engines of this type do use spark at lower and higher engine speeds but not at mid range engine speeds.

Buyers have shifted from cars to heavier trucks.

Between 1975 and 2006, market share for new passenger cars and station wagons decreased by over 30 percent. For model year 2006, cars are estimated to average 24.6 mpg, vans 20.6 mpg, SUVs 18.5 mpg, and pickups 17.0 mpg. The increased market share of light trucks, which in recent years have averaged more than six mpg less than cars, accounted for much of the decline in fuel economy of the overall new light-duty vehicle fleet from the peak that occurred in 1987-88.

Customers use improved drive trains to allow them to get bigger faster vehicles at the same level of fuel efficiency per distance travelled.

Vehicle weight and performance are two of the most important engineering parameters that determine a vehicle’s fuel economy. All other factors being equal, higher vehicle weight (which can be a proxy for some vehicle utility attributes) and faster acceleration performance (e.g., lower 0 to 60 time), both decrease a vehicle’s fuel economy. Improved engine, transmission, and powertrain technologies continue to penetrate the new light-duty vehicle fleet. The trend has clearly been to apply these innovative technologies to accommodate increases in average new vehicle weight, power, and performance while maintaining a relatively constant level of fuel economy. This is reflected by heavier average vehicle weight, rising average horsepower, and faster average 0-to-60 mile-per-hour acceleration time. MY2006 light-duty vehicles are estimated, on average, to be the heaviest, fastest and most powerful vehicles than in any year since EPA began compiling such data.

The gap is closing between the more and less fuel efficient auto makers with most of the gap closing coming as a result of more rapid deterioration in fuel economy among the makers with higher average fuel efficiency.

For MY2006, the eight highest-selling marketing groups (that account for over 95 percent of all sales) fall into two fuel economy groupings: Honda, Toyota, Hyundai-Kia (HK), and Volkswagen all have estimated fuel economies of 23.5 to 24.2 mpg, while General Motors, Nissan, Ford, and DaimlerChrysler all have estimated fuel economies of 19.1 to 20.5 mpg.

Each of these marketing groups has lower average fuel economy today than in 1987. Since then, the differences between marketing group fuel economies have narrowed considerably, with the higher mpg marketing groups in 1987 (e.g., Hyundai-Kia, Honda, and Nissan) generally showing a larger fuel economy decrease than the lower mpg marketing groups (e.g., Ford and General Motors). Two marketing groups (Toyota and DaimlerChrysler) show a slight increase in average fuel economy since 1997. For MY2006, the six top-selling marketing groups all have truck shares in excess of 40 percent; only Hyundai-Kia and Volkswagen have a truck market share of less than 40 percent and the Hyundai-Kia truck share is increasing rapidly.

Clearly people have a strong preference for bigger and faster. Technological advances will eventually enable a big drop in the cost of hybrids and other fuel efficiency enhancing technologies. When that happens cars will get faster, bigger, and moderately more fuel efficient all at the same time. Plus, people will drive more. But the only way we can substantially reduce the use of fossil fuels in transportation is to develop ways to use non-fossil fuels for transportation.

To repeat: Fuel efficiency increases are not a panacea for reducing fossil fuel usage. Only the development of competitive non-fossil fuel energy sources can make a very big impact on fossil fuels consumption.

Share |      Randall Parker, 2006 July 19 11:03 PM  Energy Transportation

Brett Bellmore said at July 20, 2006 3:33 AM:

All this is perfectly predictable, given that,

1. The price of gasoline isn't that much higher than historical levels, when adjusted for inflation.


2. That it today represents a smaller fraction of most people's incomes.

Factory said at July 20, 2006 4:00 AM:


1865 called, they want their innovative ideas on economics back.. :)

gmoke said at July 20, 2006 11:34 AM:

1908 Model T Ford: 25 miles per gallon
2004 US Fleet Average: 21 miles per gallon

Now that's progress!

PS: Ford designed the Model T to run on ethanol I understand.

Rob said at July 20, 2006 12:43 PM:

According to this article:


hybrids actually use more energy than SUVs, when you include the cost of manufacturing them and the fact that they have fairly short projected lives (only 100,000 miles for the Prius). Average old SUVs are just made of steel, rather than exotic metals or composites, and steel doesn't take nearly as much energy to produce. Hybrids also have much more complex innards, which require much more design and tooling time (all of which costs energy too).

I'd like to see more numbers and the results independently verified somewhere, but it looks like we might be fooling ourselves with hybrids.

It certainly wouldn't surprise me.

odograph said at July 20, 2006 2:46 PM:

God I hate how a marketing company can produce bullshit and have people buy it.

That's what CNW Marketing Research did for somebody, probably Ford or GM.

The full scoop is here,


but the most critical and glaring lie is that they made up figures for vehicle lifetime which totally skew the result.

National Highway Traffic Safety Administration estimates: cars: 152,000 miles, light trucks 180,00 miles, an 18% advantage.

CNW Marketing Research: cars: 100,000 miles, light trucks 250,000 miles, a 250% advantage.

Complete and unsupported bullshit.

odograph said at July 20, 2006 2:48 PM:

Sorry, the National Highway Traffic Safety Administration story:


Tom said at July 20, 2006 5:01 PM:

Brett: "The price of gasoline isn't that much higher than historical levels, when adjusted for inflation."

I guess it depends what you mean by "that much higher", and "historical levels". Since 1950, there have only been a few years where it's been significantly over $2 in 2005 dollars - 1978-1985, and 2004-now. The median looks to be about $1.85 or so (by my eyeballs), so at $3, we're about 62% above the median (sadly, I paid $3.19 the other day). The peak in 1981 was $3.01 in 2005 dollars, about the same as now.

Nice chart:
$3.01 figure

Randall Parker said at July 20, 2006 5:09 PM:


I read that CNW claim about hybrids and went digging and could find little about how they arrived at it or what competence they have for doing these sorts of analyses. They seem like a market research firm for car companies.

Anyway, I decided they hadn't proven their argument and I'm suspicious of it.

What exactly in Hybrids is going to wear out? The exhaust ought to last longer. The engine doesn't run all the time. The tires ought to last the same. Paint job ditto. Seats ditto.

The batteries look like they will last a lot longer than 100,000 miles. When it comes time to replace them the replacements will cost less. The Prius batteries have already declined in price.

Tom said at July 20, 2006 5:20 PM:

Maybe in a few years we'll all be driving these:


I guess they'll have to come down a bit though - 80 grand is a bit much. But 0-60 in 4 secs - yikes!

Randall Parker said at July 20, 2006 8:50 PM:


But incomes have risen faster than inflation. People have more buying power. So $3 per gallon today represents a smaller fraction of total income than it did in 1950. Again, rising buying power means more money spent on energy.

Tom said at July 21, 2006 4:04 AM:

Randall: That's true. Per capita GDP is more than 50% higher than it was when gas prices last peaked in 1981.

rob said at July 21, 2006 12:55 PM:

Actually, lead-acid batteries are only good for four or five years. Lithum/ions aren't a ton better (I don't know about metal hydrides, but I had some AA metal hydrides that didn't last more that 25 recharges or so).

I think the point they were trying to make in the analysis is that the hybrid cars are much more complex to manufacture, contain a lot more parts and require a lot more R&D expense than traditional cars. Since all of these activities to cost energy, it's not a specious argument. As to the exact numbers, well, like I said, I would like to see some independent verification.

Think about this, though: if you drive 10,000 miles per year, that's only about 400 gallons of gas or a little over a gallon a day. The difference between $1/gal gas and $3/gal gas is about one latte a day. Important money to some people, but not many.

Let's see what we can find...

Here: http://www.irn.org/programs/mphanda/index.php?id=011205targetaluminium.html we find the sentence:

"The electricity required to smelt a ton of aluminum, according to the Washington–based Worldwatch Institute, could power the average U.S. household for one and a half years"

An average household probably uses about thirty or forty kilowatt hours per day (going by this page: http://physics.syr.edu/courses/modules/ENERGY/ENERGY_POLICY/tables.html ), so this about 16,000 kilowatt hours of electricity. Given that a gallon of gasoline contains about 36 kilowatt-hours of energy (if you could extract it with 100% efficiency) that ton of aluminim takes around 450 gallons of gasoline to smelt, if we use it with perfect efficiency (call it 700-800 gallons in real life).

So, yes, the energy cost of one ton of aluminium is a good deal greater than the energy cost of driving a car for one year.

So, the article may be wrong, but it's not implausible.

Randall Parker said at July 21, 2006 4:22 PM:


If hybrids take a lot more energy to manufacture that ought to show up in their prices. They do cost more and some of that cost represents energy. Also, maybe the car makers are selling them for a smaller profit margin?

The cost of oil has gone way up. Has this driven up manufacturing costs for hybrids? I do not think so. Though I suspect the bulk of the energy used for vehicle manufacturing and battery manufacturing is electricity. That's coming from nukes, coal and other non-oil sources. Though natural gas is used for electricty and natural gas's cost has gone way up.

Engineer-Poet said at July 21, 2006 5:02 PM:

rob claims:

hybrids ... have fairly short projected lives (only 100,000 miles for the Prius).
Tell that to the taxi operator in Vancouver who has already driven 2 of them to well over 200,000 miles.  Each.

A hybrid's systems are inherently more long-lived than a conventional vehicle's.  The brakes don't get used as much because the motor supplies braking; the engine is off-loaded during acceleration; Atkinson-cycle engines have cooler exhaust and don't stress the valves, manifold, catalytic converter and the stuff downstream as much.  Electric motors have almost nothing to break, and motors routinely go 20 years or more without any service whatsoever.

The claim about less energy required to produce an SUV than a hybrid is similarly bogus.  A small NiMH or Li-ion battery pack takes more energy to produce than an extra ton or two of steel?  I'm sure some of the oil industry's propagandists came up with that one, because no rational human being would believe it (most people are irrational) and no honest human being would say it.

gmoke said at July 22, 2006 10:33 AM:


Vehicle Design Summit

Students at MIT have organized an eight-week summer program building five or more versions of a 300 mpg vehicle:

"Fuel Cell:  Harnessing the power of free hydrogen, the fuel cell car is a promising source of power.  California's proposed "hydrogen highway" will lead the way in a nationwide hydrogen infrastructure.

"Biofuel:  Harnessing the power of crops allows truly renewable energy.  Biofuel combustion doesn't add carbon dioxide to the atmosphere, because photosynthesis used to create the energy takes it up at the same rate.

"Human/Solar hybrid:  Human power and solar power, which run both the Tour De France and the World Solar Challenge, come together to create a vehicle completely free from fueling stations.

"Retrofit:  Make no mistake, car manufacturers are very good at what they do.  But when their safe, comfortable designs are combined with our lightweighting and efficiency expertise, the result is a car that is the best of both worlds.

"Think car:  True innovation cannot be predicted.  That's why we're making a design unrestricted by expectations.  All that we can say for sure is that it won't look like your grandfather's automobile.  Then again, maybe it will!"

Here's their full presentation

The most interesting thing to me is that these 50 students are getting together and doing it open source.  They are hacking the transportation system from the ground up, as a hack.  The Vehicle Design Summit isn't a competition but an open, collaborative design process.  These people are working together to build what they'd like to see on the road.  The more we have of this kind of activity, the we will be building an open source operating system for hardware, Linux for the concrete infrastructure if you will.

I'd like a human powered vehicle that I can ride safely and keeps my feet dry yet is light enough to be carried up three flights of stairs.

Maybe a wheelchair tricycle with pedals and hand controls, a collapsible fairing or weather skin, something light, secure, safe to operate, and protective in a crash.  Regenerative braking, electricity generating for battery assist as well as battery switching, grid and network interconnect.

Or maybe just some kind of egg or chrysalis on wheels.

"the only war that matters is the war against the imagination"
Diane Di Prima

aa2 said at July 23, 2006 1:32 AM:

Even if today's hybrids use more energy in their lifetime then a conventional ICE... it doesn't mean it isn't worth it for a nation to go for them. The USA has a 700 billion dollar trade deficit. 350 billion of that is oil imports. But if it was burning coal.. or hopefully uranium and using that energy to make hybrids.. A zero net energy gain would still be advantageous economically imo. Also when you factor in the military costs of protecting that oil supply.

aa2 said at July 23, 2006 1:39 AM:

Randall you are exactly right about efficiency gains. They are not an answer to energy problems. In the book, 'The bottomless well, why we'll never run out of energy', the authors explain that increased efficiency leads to increased total use. They made a joke that if the auto companies weren't funding research into efficiency gains, the Saudis would. And we see the example here.. People take the increased energy output and use it for larger size, more speed..

And on the issue of speed.. if it takes 1 hour to reach a destination and 3 gallons of gasoline. Or 30 minutes and 6 minuets of gasoline to move the same mass to the same destination.. The 1 hour setting is only more efficient if you consider time to have no value. But in the real world time does have value.

I dont know how, but when we go to all electric powered vehicles I wouldn't be surprised to see increased energy use. Maybe we will have ultra fast cars, and thus travel far further then we ever have before on a daily basis.

Engineer-Poet said at July 23, 2006 7:24 AM:

Electric vehicles are much more efficient than ICE (at least from wall/pump to wheels) so energy consumption would drop.  Battery-related limitations to range will also hold energy consumption down for a while.

Randall Parker said at July 23, 2006 7:38 AM:


When computers get smart enough to operate cars more safely than humans can then the risk of travelling at higher speeds on highways will go down. Vehicle speed and therefore energy usage may rise at that point.


Interesting point. In the early stages electricity will lower the costs of short range travel relative to long range travel.

What would lower time spent on roads: Ultra-low crime rates. People would be more willing to live in cities if crime rates were much lower. Maybe CCTV video cameras watching streets will make them safe enough to bring people back to the cities. There's already a trend in some areas for affluent people to reclaim some cities.

Nick said at July 23, 2006 11:50 AM:

"Based on sales projections provided by automakers"

The mix of vehicles is changing, but Detroit keeps projecting lower gas prices and a traditional sales mix. They hung their hats on the EIA projections of lower gas costs as long as they could. Wishful thinking, and a desire to convince creditors and customers that things will get better - fear of bankruptcy isn't good for corporate bond interest rates, or sales!

Engineer-Poet said at July 23, 2006 12:09 PM:

GM's bonds are already at junk status, how much worse can it get for them?

Sumyung Guy said at July 26, 2006 7:32 AM:

Here at July 26th, I doubt a lot of folks are reading the comments on this page anymore. But I did want to point out that I've read as of this month that GM has taken a large second quarter loss and is blaming it in part on lagging sales of their light trucks and SUVs. An article in Green Car Congress: http://www.greencarcongress.com/2006/07/ford_reports_un.html talks about just this fact, I believe.

I don't doubt that many idiots will buy larger vehicles that "go zoom zoom really loud!", but at the same time other folks not quite as stupid seem to be buying less gas guzzlers. Even here where I live, in the heart of "Bubba land" (hey, I'm a Southerner, I can crack a joke at the Bubbas if I want to), I'm seeing more and more hybrids on the road.

Maybe things aren't quite as hopeless as they seem?

Paul Dietz said at July 26, 2006 9:27 AM:

Maybe CCTV video cameras watching streets will make them safe enough to bring people back to the cities.

Particularly if coupled with powerful computers to read license plates and identify individuals. Extremely
dense and cheap video storage would also be useful, particularly with compression algorithms that preferentially
preserve high fidelity data of human faces, possibly zooming the camera to take mugshots as people pass.

Randall Parker said at July 26, 2006 4:17 PM:

Sumyung Guy,

Gasoline prices have finally gotten high enough for them to cut American demand for big cars. But I'd be surprised if the average fuel economy of vehicles sold in the USA went up by even 5 miles per gallon as a result of current fuel pries. Maybe aat over $4 per gallon we'd see a shift that big in fuel efficiency of average purchased car.

What I'd like to know: Average vehicle fuel economy and gasoline prices per Western developed country. But Americans have higher per capital income. So even if we had German or British gasoline prices we'd still buy larger cars than they buy.

Another thing to watch: Average miles driven per year. Will people move closer to work and take jobs closer to home due to higher gasoline prices?

Will D said at August 8, 2006 7:52 PM:

Higher output batteries ( out very soon ) and increased solar cell efficiencies will make that 30 square feet on top of your car valuable for more than bird droppings. DC motors are simple and so is the reasoning behind squelching the promotion, research and advance of hybrids and electrics.

We'll look back on this...

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