EPA estimates skewed

[capnbass91]

Combined EPA estimated mpg is based on 45% highway and 55% city driving, FEcomb = 1 / (( .55 / city FE) + (.45 / hwy FE))

That isn't fair for those of us that do far more city than highway driving, where it should be closer to 10 and 90%, makes us look bad! That ratio would be:
FEcomb = 1 / (( .90 / city FE) + (.10 / hwy FE))

Using that average and excluding my recent trip to Twin Lakes, my combined mpg rating for my car would be 18.5, which is exactly where I'm at

Anyone else do far more city than highway driving? And find that the 45-55 ratio doesn't correctly apply to you?

[graydonengineering]

With the roads around here I get much better mpg in the city so the proposed ratio would put me much further ahead of EPA than I am. The speeds are 45 in town and the lights are far appart. I anticipate, coast, key off and fight my way up to a 30-35mpg average. On the highway it's nothing but open thottle, no cheating and my mileage is closer to EPA. My FE falls off a cliff once I exceed 50 mph. I hope to change that with a full belly pan.

[Diesel_Dave]

Sure, the EPA estimate can be skewed by where you have the drive, however, HOW you drive greatly affects the relative difference of city & highway.

For example, if you drive like a "normal" person in the city (accelerating fast, breaking hard, paying no attention to timing of red lights, etc.) you will get close to the EPA city estimate. However, if you adjust you driving style so as to not waste all that energy your engine produces, you'll be suprised how much better you can improve you city mileage.

[SentraSE-R]

^^^ What Dave said. If you're actually getting EPA figures, you're not trying nearly hard enough.

[redyaris]

The EPA FE test are for the perpose of comparing vehicals against a standardized test. The only way to get the same outcome is to drive in the same pattern as the test cycle. There is no way to get a test of this sort that will suit every situation or driver.
Every publication about the fuel consumption of motor vehicles says the same thing... your fuel consumption may vary based on...

[capnbass91]

I know I'm not as extreme as some people here, but I try very hard to get good mileage.

Where I live there are a lot of lights and so lot of stops.
I have the same problem, once I get above about 50 it gets much harder to get even 30 mpg.

I have a partial belly pan and it's helped a noticeable amount.

[SentraSE-R]

If you're driving an automatic in city conditions, you've got the worst possible combination. OC has to be pretty awful as far as city traffic goes. You may be doing as well as possible, given your location.

[jsatter]

You can still work to improve city mileage by only accelerating enough to get you to the next stop and trying to time the lights. It can be a pain sometimes, and people will get annoyed with you at times. Planning routes more efficiently can help a lot as well. Sometimes it's better to go a few miles out of the way because the route is more FE friendly.

That said, when I do more city driving, my mileage does take a hit, but I still manage better than EPA mileage. The ratings do give a range for city and highway mileage now though, and I figure you can hit the higher end of the range if you drive smart.

[Kodak]

Yeah, I hear what you're saying capnbass.

It's hard to translate real life city driving from the very specific EPA city test. Driving in NYC or LA traffic will be much different than a smaller, less populated city. Are they both 'city' driving? Yes, but the commutes would be very different. That's why it's hard to get a precise city:highway percentage.

I don't even bother trying to estimate a percentage. I just know that my commute is not a true highway trip, but has fewer stops than a real city trip. So it's somewhere in the middle, just not sure where.

[capnbass91]

Yep, auto tranny in OC. Oh how I would like to live somewhere more rural!

I've started turning my engine off at lights that I'm familiar with and know the timing well.
Accelerating slowly goes against my racing video game upbringing, but it's becoming more natural, and my mpg is showing it.