When CAFE Meets EPA: A Tale of Two Fuel Economy Standards

By John O'Dell May 20, 2009

2009chevroletcobalt.jpg By John O'Dell, Senior Editor

OK, gulp down a couple aspirin, take a few calming deep breaths and bear with us: we're about to try to explain why 35.5 miles per gallon doesn't really mean 35.5 miles per gallon as far as the average consumer is concerned.


2009 Chevrolet Cobalt already achieves CAFE standard for 2016 model year.


One of the few secrets that Washington has managed to keep is that the fuel efficiency numbers politicians toss around when discussing the "corporate average fuel economy," or CAFE, standard are not the same as the EPA fuel efficiency numbers that  journalists and most everyone else use when discussing mileage and that consumers have been trained to look for when shopping for a new car.

So while the new federal fuel economy program announced by President Obama this week sets 35.5 MPG as the federal fuel efficiency standard for 2016, it doesn't necessarily  mean there will be a lot of cars and trucks in the market seven years from now with wndow stickes tht boast of 35.5-miles-per-gallon fuel economy.

Indeed, the CAFE number can be achieved by a fleet of new vehicles that gets an EPA fuel economy average of just 27 miles a gallon.

Confused? Don't feel bad. It's hard not to be confounded by the way the government uses two different methods to measure miles per gallon.

On the plus side, we're talking about a 30 percent increase in average fuel economy from today's standards, and setting it is a coup for the administration because it marks first time automakers and environmentalists have lined up with the government and agreed in advance to support a CAFE increase.

But that's not going to help car shoppers wondering, as many already are, what 35 MPG cars are going to be like - will they be so light and small a Mini or Smart would dwarf them? 

Some also wonder whether the auto industry will be able to offer much in the way of variety, or low price, in vehicles that meet the new CAFE standard. After all, there are only five cars sold in the U.S. today - all hybrids - that get better than 35 miles per gallon.

But converting CAFE to EPA fuel economy, changes the picture: There already are quite a few cars and trucks with the requisite EPA fuel economy numbers, and many more that are close and wouldn't need much of a push to get over the hump,

Green Car Advisor examined the problem of EPA vs CAFE fuel economy the last time there was a big CAFE change, and today we'll try to update things to make some sense out of what the president has just proposed.

The president didn't change CAFE, which was just revised at the end of 2007. Instead, he moved the deadline for hitting 35.5 MPG up from 2020 to 2016. He also announced, for the first time since the standard originally was set, the individual car and truck standards: Passenger cars must average 39 miles per gallon, light trucks 30 MPG.

The rules don't mean all vehicles have to achieve the CAFE standard - it is an average, not a minimum. There just have to be sufficient vehicles in the national fleet that get more than 35.5 MPG to offset those that don't make the grade.

And remember, we've been talking about CAFE numbers.

In the real world - or as real as we can get - the cars and trucks on dealers' lots are still going to be wearing EPA fuel economy labels. And it only requires an EPA rating of 29 miles per gallon for a passenger car to equal the CAFE rating of 39 MPG, while 23 MPG on the EPA scale equates to the truck segment's CAFE standard of 30 miles a gallon.

Finally, there's no requirement that consumers use the CAFE numbers when shopping for new vehicles. Except for the higher fuel costs of a less-efficient vehicle - and the potential of reduced resale value - there's no penalty for buying a 15 MPG truck or 24 MPG car just because the CAFE standard for each type of vehicle is higher.

CAFE isn't meant to directly change consumer attitudes and buying habits - as would a fuel tax or registration fees based on fuel-economy. Rather it is a political tool aimed at dictating, to a degree, the types of vehicles the industry will be able to offer.

Click the links below to see the cars and trucks available today with EPA fuel economy ratings that meet the 2016 CAFE standard.

EPA Combined Scores Passenger Cars.pdf

EPA Combined Scores Light Trucks.pdf

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08_miata says: 6:48 AM, 05.21.09

Wow, so really we're just looking at 29 MPG for cars and 23 MPG for trucks?

Okay, so maybe it's not as bad as I thought. A lot of existing cars get close to that as it is. The rest may just need some tweaking to transmission ratios or engines.

And then, too, this is only the "average" required. So looks like the death of the V8 engine may once again be an exaggeration :)

uncanny_man says: 3:26 PM, 05.21.09

Still, the average fuel economies of the manufacturers needs to jump from around 27 (cafe) to around 35 (cafe). That is still a required increase of 30% from the current average with all of 7 years (about 1 product cycle) to do it. Goodbye horse power, I hope we meet again someday.

cwc1 says: 6:32 PM, 05.21.09

I don't quite get it. The previous CAFE standard was 27.5 MPG, which it had been since the mid 1980s and was based on the old numbers. So if the new standards are still to be based on the old numbers which when adjusted come to 27 MPG, don't current auto fleet totals already meet or exceed that standard?? (or the ones that don't are paying fines for not meeting 27.5 which is now 26??).

It makes about as much sense as Coca Cola's product mistake with New Coke (also from the '80s). This was when New Coke was introduced, which replaced the original Coke, but people didn't like New Coke as much, so Coca-Cola re-introduced the Old Coke as Coke Classic, which effectively became the New Coke since it had been off the market for a while having been phased out in favor of the original New Coke, which itself has since been phased out.


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