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35.5-mpg CAFE Explained

It's Not as Bad as it Seems

More details are coming to light on the coming Corporate Average Fuel Economy and Greenhouse Gas requirements, and many of these details make the 35.5-mpg target a bit less daunting. For example:
More on Motortrend.com:
35.5 mpg doesn't REALLY mean 35.5 mpg Most folks confuse CAFE numbers with the gas mileage they get, or what's promised on the window sticker, which these days seems pretty far away from 35 mpg. The mainstream media seldom draws any distinction, and the government is in no huge rush to clear this up because downplaying the impact of this environmental legislation doesn't do them any good. CAFE figures are based on the raw fuel-economy numbers that come out of the EPA city and highway fuel-economy tests, which have been in use and essentially unchanged since 1975. What goes on the window sticker is a corrected number, calculated to better represent the real-world economy drivers will experience. The engineers and scientists at EPA did a helluva job updating these correction factors for 2008, bringing the often publicized EPA City and Highway ratings very much into line with what we observe on our long-term test cars. A total of 33 models achieve 35.5 mpg or better uncorrected combined fuel economy today, including every four-cylinder hybrid (as expected) plus most Minis and Civics, as well as bigger conventional cars like the base versions of the Chevy Cobalt, Ford Focus, Mazda3, Nissan Versa, and Saturn Astra (all of which average 27 or 28 mpg combined on the sticker).
More on Automobilemag.com:
The Greenhouse Gas target of 250 grams/mile by 2016 would equate to 35.5 mpg, but it won't all have to be achieved on the EPA city and highway tests. The government understands that many improvements to vehicle efficiency won't show up on the EPA tests. The two main tests are run with most accessories like the air conditioning switched off, so any improvement in power consumption of these items is lost. EPA is working on test procedures that will give credit for these improvements and may allow A/C credits accrued before the start of the program to carry forward. Other accessory items like solar roof panels, active aerodynamics, adaptive cruise control systems (especially those on the near horizon that take elevation changes into account), and myriad other efficiency boosters will likely be used to generate some credits toward meeting the 250 gpm limit. Flex-fuel vehicles boost CAFE a bunch, but only until 2019. Any vehicle that can run on E85 (85 percent ethanol, 15 percent gasoline) gets to average the fuel economy when operating on gasoline with the fuel economy running on the flex fuel, but the latter calculation counts only the gasoline content (15 percent), which has the effect of multiplying that fuel economy by 6.67. Let's look at the example of a flex-fuel Crown Vic:
More on Automotive.com:
Average combined fuel economy on gasoline: 24.1 mpg (uncorrected)
Average combined fuel economy on E85: 17.6 mpg/0.15 = 117.2 mpg
CAFE figure: 1/(0.5/24.1 + 0.5/117.2) = 40 mpg
For convenience, this same 15 percent (6.67x multiplier) is used for gallon-equivalent values of other flex fuels like natural gas, even on dedicated natural-gas vehicles like the Civic GX (100 cubic feet of natural gas = 0.823 gallon of gasoline equivalent): Average combined fuel economy: 37.5 mpg (equivalent) / 0.15 = 250.1 mpg The caveat: The combined effect of such alternate-fuel vehicles on a company's overall sales-weighted CAFE can be no more than 1.2 mpg for the next few years, and then it will phase out under a schedule shown below. The Greenhouse Gas folks, however, are contemplating extending the credit if manufacturers can demonstrate that the alternate fuels (in flex-fuel vehicles) are actually being used.
Model year Allowable CAFE mpg increase
1993-2014 1.2
2015 1.0
2016 0.8
2017 0.6
2018 0.4
2019 0.2
After 2019 0.0
Different manufacturers will have different CAFE targets Yearly fuel-economy targets will be established based on each car's footprint (wheelbase times average track width, expressed in square feet). For 2011, the curves for passenger cars and light trucks look like this:

Based on the footprints of the vehicles offered, and the projected sales volumes, the anticipated CAFE targets for each manufacturer are:
  Cars Trucks
BMW 30.2 25.7
Chrysler 28.6 24.2
Daimler 28.9 24.5
Ferrari 30.7 -
Ford 30.1 23.6
General Motors 30.0 23.3
Honda 30.6 25.4
Hyundai 30.3 25.3
Maserati 27.5 -
Mitsubishi 30.9 26.7
Nissan 30.5 24.0
Porsche 31.2 25.5
Subaru 30.9 26.6
Suzuki 31.0 26.4
Tata 27.5 26.1
Toyota 30.6 24.8
Volkswagen 30.9 24.9
Sales-weighted Average 30.2 24.1
The curves are established in advance and the targets are computed at the end of the sales year, so manufacturers only have to achieve the footprint target for each vehicle, and there are no reprisals if the sales mix tilts unexpectedly in one direction or another. It does beg the question whether today's designers are being encouraged to "push the wheels to the corners" more than ever to maximize footprint and reduce the economy target. What about Electric Vehicles? Electric vehicles will be tested the same way as combustion-powered cars, using the two main city/highway tests for CAFE and measuring energy consumption in watt-hours/mile. A gallon of gas contains 32,705 watt-hours of energy, but this number is reduced by a 0.328 factor for fossil-fuel electricity efficiency, and by 0.924 for electricity-transmission efficiency; then it's divided by 0.830 to account for inefficiencies in petroleum refining, bringing the conversion to 12,307.3 Wh/gal. This number then essentially gets the 15-percent flex-fuel incentivizing factor (6.67x), described above, bringing the conversion factor to 82,409 Wh/gal unless there are any petroleum-fired accessories (like a heater) onboard, in which case the factor drops to 73,844 Wh/gal. Expect CAFE mpg numbers in the triple digits, and these are not expected to be subject to the flex-fuel CAFE cap mentioned above. These won't show up on the window sticker. They're expected to be corrected down the same way combustion figures are. The big unknown: Plug-in Hybrids This is the last piece of the puzzle and it is still being determined. The solution is expected to involve running each cycle repeatedly until the fully charged battery drops to the level at which the onboard engine provides most of the propulsion. Then the vehicle will be run in this mode again. The charge-depletion range is then calculated and the measured electrical and fuel energy used during the charge-depleting and charge-sustaining modes will be combined using a utility factor that predicts what percentage of the population's daily driving distance is at or below the charge-sustaining range. But the details of how these figures will be reported for CAFE and on window stickers won't be finalized until late summer. We'll be back then with details.

very good article makes cafe look less scary!


Don't worry ExoticSuperCarFan, the fine is so small you won't notice it in the base price of a Civic let a lone a Ferrari. That's why Mercedes Benze just pays fines and rolls into the price of the car.CAFE = wrist slap

bojangles beast
bojangles beast

Man this looks like Flex-Fuel will be the claue American car companies need.


Wow, that article did nothing to pacify my fears. Okay, so the base Chevy Cobalt meets the new CAFE standards. Big deal. I don't care about Cobalts; what about the Corvette Z06 and ZR1? Are they going to get 39mpg? No. What about Ferraris, which must apparently average about 30mpg? How are they going to do that making only supercars? They're either going to have to make them all hybrids of some sort (boo!) or make a smaller fuel-efficient model (see: Aston Martin Cygnet--boo!). More likely they'll end up paying fines on all of their vehicles, which means the prices of their cars will go up even higher (boo!). Anyone who wants a nice car had better buy one soon, because the prices of them will skyrocket once this legislation goes into effect.


That's very cynical. I for one am not the type of person that blames the "evil rich people" for all of our problems. Ever hear of Carbon Credits? That's just a huge scam so Al Gore can make more money trying to scare the pants off of everyone with his "we're killing the Earth BS".Cars contribute to less than 1% of the carbon dioxide in the atmosphere. We should focus on real problems like famine, genocide and our 3 trillion dollar deficit.


Please, you think if they did something that would make a difference they could garner enough support for it? Of course not. Why? Because powerful people would lose money. We demand change, but are unwilling to pay the price.


Um you realize that the requirement is 39 for cars and 30 for trucks, right? Do even the small cars of today meet the combined 39 mpg target?


They're not going to explain this because they want to pacify the "Green" community. Liberals do what makes them "feel" good, not necessarily what's actually going to make a difference.


They dont want the public to know all of this because it would show how many holes are in the new rules. All of this is done to avoid raising gas taxes.


Now I don't feel so bad. This does explain a lot, and I wish this were brought to the public's attention.


Good article. Thanks!

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