The Truth About EPA Fuel Estimates
You've seen the stickers on the windows of cars and in today's modern times most car buyers know that there is a difference between the city miles per gallon and the highway miles per gallon. These estimates are provided to car manufactures from the Environmental Protection Agency's Federal Test Procedure. Looking at stickers like the one pictured on the left, these mileage estimates gives car buyers and people looking to rent fuel efficient cars a somewhat accurate idea of what type of mileage they should get for a particular vehicle. Based on these statistics people feel fairly confident that they can buy or rent a car and be fairly close to the sticker mileage when actually driving the car. But how accurate are these estimates? Would you believe that for quite some time, these tests were entirely unreliable.
Now and Then
If you've ever wondered how these tests are done here's the basic breakdown of procedures that were first established in 1977 by the Environmental Protection Agency...
For the City MPG test, the car runs at an average speed of about 20 mph and a top speed of about 58 mph for about 7 miles.
The Highway MPG test runs for a little bit more than 10 miles, averages at a speed of 48 mph and topping out at 60 mph
Dealing with a cavalcade of complaints about unrealistic mileage estimates (does the average driver actually follow a driving pattern like those tests?) the EPA re-assessed their testing about 20 years ago. But did it make a difference? Not exactly.
City versus Highway
Not too long ago Consumer Reports published a series of articles on the accuracy of EPA mileage estimates revealing that the biggest inaccuracies showed up in the tests for city driving. Remember the test? Now imagine doing that test on a fuel efficient or hybrid car rather than actually taking it out and driving it around a city? In some cases hybrids were rated a good 10 to 20 miles short of the tests done by the EPA. Which means while you're driving thinking you're getting 55 miles a gallon you might actually only be getting 40.
A Change is Coming
Continued complaints and reports like ones from top consumer magazines finally started making an impact on the EPA's testing procedures. As such, the EPA in the last few years started to replace the decades old model with a more updated system that's a little more realistic. Factoring real-world variables like idling, faster driving, acceleration and braking the EPA even started to take account of the new technology of today's modern cars. What many people don't know is the EPA doesn't actually test for fuel efficiency but rather it actually issues guidelines that automakers then use to do their own testing. The most important thing for people to remember is regardless of what the sticker says at the dealership or the rental car agency do your research and make an informed decision.