Filed under: Green
Cars.com creates True Mileage Index to debunk CAFE
In an effort to expose the underreported truth behind the government's corporate average fuel economy ratings (CAFE) and to define more accurate fuel economy estimates, the team over at Cars.com has created their own True Mileage Index. The consumer website points out the flaw behind CAFE is that the adjusted calculations misrepresent the numbers posted on new car windows, and the actual fuel economy consumers will realize on the road (e.g., although Honda earned a 2007 CAFE rating of 33.5 mpg, no Honda has a combined mileage of better than 31 mpg). Like the CAFE calculation, the True Mileage Index analyzes a number of factors. However, Cars.com places more weight on actual sales volume, and less on alternative fuels (like E85). Their math places Honda's True Mileage Index at a more realistic 24.9 mpg. In a nutshell, don't get overly excited when you hear that the 2020 CAFE number is going to be 35 mpg -- it's likely to only increase your future vehicle's actual fuel economy by a few mpg.
[Source: Cars.com]
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Reader Comments (Page 1 of 2)
Red Star 7:11PM (8/01/2008)
My Fusion 2.3L is rated at 20/29.
According to car's computer, I get 26/40.
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csquirrel 7:48PM (8/01/2008)
26-40... that's a wide margin of error, lol. Me thinks your computer is optimistic on the high end =]
tom 7:43PM (8/01/2008)
The Fusion's computer calculates city/ highway?
Dave 7:11PM (8/01/2008)
2 whiney kids in the backseat and 4 stops on a Saturday afternoon will kill any thought of gas milage as the gov't. reports.
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compy386 7:15PM (8/01/2008)
First of all you can't compare CAFE numbers with EPA fuel economy estimates. They're not the same thing. Second, it all has to do with how you drive. My EPA fuel economy rating for my 2005 Focus is 29 highway, yet I regularly get 32-34 highway because I drive the speed limit. Coming up with a better average is fairly meaningless because not everyone drives the same way. I know based on my driving that I get about 10% better than EPA numbers. I make my vehicle purchasing decisions accordingly.
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Seoultrain 7:35PM (8/01/2008)
With all this rage about gas prices and mpg, TMI is a very fitting moniker.
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Matt 7:41PM (8/01/2008)
Haha, very good point. Cars.com is trying to be like Edmunds, and that's like CompUSA trying to be like Best Buy. Close, but then again, no so much.
Shadyman 7:50PM (8/01/2008)
More like TMFI...
paul34 8:13PM (8/01/2008)
I regularly beat EPA estimates on my tC, especially considering I drive city. However, the difference is that I know a thing or two about saving gas, plus I drive the 5-speed (manual).
The point is, most people don't know squat about saving gas. Usually the extent of their "knowledge" is some water cooler talk they heard about going 45 all the time on a 70 MPH highway in the left lane with the windows wide open, AC blasting, and hundreds of pounds of trash in the trunk and backseat (including trashy passengers).
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paul34 8:14PM (8/01/2008)
BTW, I realized my comment sounded like boasting; sorry, didn't mean to be. I'm not gas-saving expert like really hardcore hypermilers, but I do try to learn some true facts, and decide for myself whether it makes sense. Then I try to apply it - consistently.
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Noz 3:15PM (8/03/2008)
Well...that's still better than most. Most people are just idiots...both in the way they act and the way they drive.
Wanderer 8:19PM (8/01/2008)
I have a 1998 Toyota Corrolla, drive 75 mph with the A/C every day and get 40-41.
How is it that in 10 years cars don't get that kind of mileage???
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nardvark 8:40PM (8/01/2008)
because your 98 Corolla is, relatively speaking, a deathtrap.
Wanderer 9:09PM (8/01/2008)
Brilliant reply. That has nothing to do with mileage.
Majarvis 9:27PM (8/01/2008)
Actually, it has everything to do with mileage. Cars today are heavier than cars 10 years ago due to increased safety systems in vehicles, which addd weight. Added weight decreases fuel economy.
FordTruckin 9:45PM (8/01/2008)
Actually it does....weight. 1998 Corolla = ~2400lbs 2008 Corolla = ~2500lbs. Aerodynamics also take into account as well was the dimensions of the vehicle. This isn't a great example but there are some cars that weigh several hundred pounds more than a 10 year old model because of the safety features adding weight
jordan 11:43PM (8/01/2008)
It has everything to do with mileage...your lighter car wouldn't survive as well in crash tests as today's cars would, no doubt about it. now i'm not going to go as far as to say that yours is a deathtrap, but i will go as far as to say that no auto company would make a car like that now because of all the other BS that they have to include in cars now :)
Harrison 2:41AM (8/02/2008)
Your Corolla has less power and weight. Besides, your driving style does not = the EPA style; therefore we have no idea what a 2008 Corolla with similar options will get with your style.
BillySharps 9:57AM (8/02/2008)
His car has fewer safety devices, which makes it lighter, which means it can have a smaller engine and still get the same performance with better fuel economy. Fewer safety devices means that it is a death trap, relatively speaking. It has everything to do with mileage.
azzo45 1:33PM (8/02/2008)
because your 98 Corolla is, relatively speaking, a deathtrap.
He said it was 1998 Toyota... not 1978! Christ, the car is 10 years old & came from an era with airbags. Death trap because its not "5-Star" crash rated?
What else do you get overdramatic about???
So a lightweight car is an UN-SAFE car? Guess I'll pass on that ultra light Lotus... must be a "death trap" eh?