How do you feel about the EPA mpg rating change in 2008?

[tim3058]

Didn't like the new numbering system at first, sounded like a scam to tweak CAFE ratings, but from what I can tell since the numbers are pretty realistic now. Sounds like a bunch of you were already over the EPA, but for my truck that had an EPA like 16 city/20 highway I -never- got over 17 to a tank, even with a 40 minute highway commute, and babying the gas taking off. I was pretty annoyed back then, but the new numbers are like 14-18, putting average at 16... which put my 17 mpg about 6% over EPA... these days it gets around 16 mpg with the 10% ethanol... seems like the adjustment is right-on.

[Nevyn]

The CAFE test hasn't been changed since 1975. By CAFE, a 2010 Mustang GT with the 4.6L V8 gets 33 MPG highway. By EPA 08, its rated just 24 MPG.

[gone-ot]

CAFE is what the vehicle is tested to (emissions based)

EPA is what the vehicle is advertised as being capable of getting (milage based)

[PaleMelanesian]

My civic's ratings:
CAFE: 37 / 49 mpg (41 combined)
old epa: 33 / 38 (35)
new epa: 28 / 35 (31)

According to any current and future CAFE requirements, my car gets 41 mpg.

[Piwoslaw]

Should CAFE testing be changed to be more realistic?

As for the new EPA numbers it's good that testing is closer to real life so people know what they are paying for. But a side effect of lowering the EPA is that for many people the target FE is lower. Here's what I mean:
Say a car's old EPA is 35 and new is 31 (as in Pale's example). Someone who bought it pre-2008 may decide to keep an eye on FE. If it's something like 33, then he'll think: "Well, I'm below average and I've gotta do something about it. How about I go a little slower on the freeway, oh and maybe check out that EcoModder.com site everyone at work is talking about?" (EcoModder.com is just an example, I am in no way related to it, nor am I not trying to crypto-advertise it)
On the other hand, if he buys the car with a big 31avgMPG sticker on the window, then when he calculates his 33 tank average he'll get all happy and keep driving like he used, b/c he's above average.

[5speed5]

Originally Posted by Piwoslaw

Should CAFE testing be changed to be more realistic?

As for the new EPA numbers it's good that testing is closer to real life so people know what they are paying for. But a side effect of lowering the EPA is that for many people the target FE is lower. Here's what I mean:
Say a car's old EPA is 35 and new is 31 (as in Pale's example). Someone who bought it pre-2008 may decide to keep an eye on FE. If it's something like 33, then he'll think: "Well, I'm below average and I've gotta do something about it. How about I go a little slower on the freeway, oh and maybe check out that EcoModder.com site everyone at work is talking about?" (EcoModder.com is just an example, I am in no way related to it, nor am I not trying to crypto-advertise it)
On the other hand, if he buys the car with a big 31avgMPG sticker on the window, then when he calculates his 33 tank average he'll get all happy and keep driving like he used, b/c he's above average.

That's a good point I hadn't thought of. Another one is it de-emphasizes the mpg advantage of smaller cars.

For example, say your an average American that wants a new car with auto transmission. If you're on a Chevy car lot trying to decide between an Aveo (25/34 mpg),
a Cobalt (24/33 mpg) and a low-end Malibu (w/o 6-spd auto, 22/30 mpg), mentally you say, "okay, they're all low-mid-20's city and low-30's highway", so it probably doesn't affect your buying decision that much.

However under the old system, you'd see Aveo (28/39), Cobalt (27/37), and low-end Malibu (25/34). Now the impression is, "okay the Aveo and Cobalt get high-20s city, high 30's highway, the Malibu gets mid-20s low-mid-30s highway" (There's also more of a separation between the Aveo and Cobalt.) That could steer you more toward the smaller cars. You weigh the higher gas mileage with the lower price of the smaller cars and say, "I'll take the Cobalt".

(BTW, I'm using the 12% that the EPA said was the average decrease in mpg...meaning I multiplied the new numbers by 1/(1.0 - 0.12) = 1.136 and then I rounded to "convert" back to the old system)

[cfg83]

5speed5 -

The old EPA is closer to what I used to get as a conservative driver. The new EPA makes my signature look good, but I prefer the old EPA because it makes the % over EPA more challenging. However, I use the new EPA in my garage entry because that is the new standard by which new cars are being judged.

CarloSW2

[5speed5]

Originally Posted by cfg83

5speed5 -

The old EPA is closer to what I used to get as a conservative driver. The new EPA makes my signature look good, but I prefer the old EPA because it makes the % over EPA more challenging. However, I use the new EPA in my garage entry because that is the new standard by which new cars are being judged.

CarloSW2

I do the same and I noticed most everyone else does too. I think that's the correct thing to do. They should all use the same standard and the new cars don't have the old standard.

One positive thing that I will say about the new standard is that I believe it
has spurred some of the carmakers (GM, Nissan, Toyota and Ford come to mind) to get their midsized cars back above 30 mpg highway and to get the
compact cars back in the high-30s highway. In fact, I think that may have been the sole impetus for the Cobalt XFE.

[wagonman76]

With my cars, with the old numbers, and before hypermiling or mods, I was getting the EPA figures pretty much right on when going downstate and back.

[Christ]

Originally Posted by Daox

I'm pretty sure the CAFE test is different than the EPA test. Thus, you get 33 mpg on the CAFE test, but the EPA test you only get 30 mpg. They aren't the same test.

I thought CAFE was based on EPA test cycle readings?

I didn't know there was an actual test to enforce CAFE, I thought it was just a law that said that the average fuel economy per class had to be "X" with future increases, which is where my assumptions came from.