EPA Mileage Estimates

Has the relationship to real world driving and EPA mileage estimates improved?

The new system is better than the old system, but the phrase “your mileage may vary” is still appropriate. The estimates cannot account for every driving situation. You may get better or worse than the estimated mileage, depending on how and where you drive.

I honestly do not know the actual protocol changes, but my understanding is that it was changed to make the tests more consistant with and the estimates more accurate relative to real world driving.

I have to say that I’ve always gotten the EPA estimates on my cars when I drove conservatively and in nice weather.

Absolutely. And this has created an interesting phenomenon: People look at the ratings for new cars and see little or no improvement over the ratings given their older cars, and descry the lack of progress in fuel economy ratings, not realizing the numbers aren’t comparable.

It changed beginning with the 2008 model year.

The old figure, like the old SAE horsepower ratings were ideal situations, and were based on very leisurely driving, slow acceleration and accessories off. The new driving cycle is more realistic and resembles the real world conditions better. A good driver , as stated should be able to get the mileage advertised.

I’m not sure if the hybrid figures, which were wildly optimistic before, are much better. In cold weather the engine needs to run to power the heater, while in hot weather it’s needed for the A/C. In Seattle or San Francisco, you will get very good mileage from your hybrid, in Canada, probably not as good.

I believe that there was some kind of undefined irregularity in the EPA procedure. Our 05 car could barely exceed the old EPA highway mileage number. Our new 08 can barely exceed the new EPA highway mileage number. Same driver; different car brands; go figure.

It must have always been politics for EPA’s estimates to be unrealistically high. From the first year, many people were complaining that the mileage estimates were too optimistic by 15% to 20%. Did EPA ever use a 15% to 20% correction factor? NO! Now, after all these YEARS, they are issuing figures that are more like the rest of the country are getting, and have been getting for decades!

The old rating or new rating…it doesn’t matter. You ONLY use it to compare one vehicle to the next. You do not use to determine how much gas you’ll be spending each year based on the miles you drive. The best you can do is say that this vehicle gets better or worse gas mileage then this other vehicle…PERIOD.

I think many people do use the EPA figures to guessimate their fuel usage for a period of time, rightly, or wrongly.

Yes. I get a little better than EPA highway during my highway commute. As Mike said, use it to compare vehicles. If one car gets 10% better mileage in the EPA estimate, then it would get about 10% better mileage for you compared to the other car. Exact mileage may not be the same beasue their test conditions may not be exactly the same as your drive.