It’s nearing the time when I’ll have to buy a new car, so I’ve been comparing fuel economy ratings on various cars. Some of the estimates are much lower from the original mileage estimates for my current car, which seemed odd. Then I remembered that the EPA issued new gas mileage ratings. I looked into the reasons for the change and what the new numbers mean.
Why the New Gas Mileage Ratings?
The old Highway and City mileage ratings used for cars manufactured before 2008 were developed in the 1970s. Cars and driving habits have changed a lot in the last 30 years, so additional tests and factors were added to more accurately reflect modern driving habits.
New Gas Mileage Tests
According to the EPA’s 2008 mileage guide, ratings represent the following driving experiences:
- City: “urban driving, in which a vehicle is started in the morning (after being parked all night) and driven in stop-and-go traffic.”
- Highway: “a mixture of rural and interstate highway driving in a warmed-up vehicle, typical of longer trips in free-flowing traffic.”
In addition, they’ve added tests for:
- More aggressive driving (rapid acceleration, higher speeds, and hard braking)
- Driving at high speeds
- Air conditioner use on a hot day
- Cold weather city driving.
The new window sticker still shows city and highway ratings, but it also indicates a mileage range.
What It Means for You
If you already own your car, then the new ratings don’t mean much to you. If you’re buying a new car, then they mean a lot. You can’t simply compare the mileage of your old car with the mileage on the new stickers. If you have car from 1985 or later, you can compare the old MPG estimate with the new one. For example, my 1997 Corolla was originally labeled at 27 city and 34 highway. The adjusted estimate is 23 and 31.
Some cars fare well under the new standards, but hybrids took a big hit on gas mileage estimates. The 2007 Toyota Prius originally tested at 60 city and 51 highway. The new estimates for the same car are 48 and 45. That’s still very good mileage, but not nearly the mileage people expected to get.
Of course, actual mileage will vary, but the new estimates will give you a much better idea of what you can expect from your new car. By comparing new car stickers with the revised estimate for my Toyota, I can also get a better idea of whether the new car will improve my gas mileage and reduce my fuel costs.