Gas mileage of hybrid vehicles put to the test

Hybrid cars tout their great gas mileage, but how many miles to the gallon are they really getting? Consumer Reports has partnered exclusively with 7 On Your Side to find out.

People who care the most about getting great gas mileage may be disappointed to learn what Consumer Reports' latest tests have uncovered. It turns out hybrids - while some of the most fuel-efficient cars on the road - are all too often coming up short.

When you're shopping for a new car, the window sticker says how many miles-per-gallon you can expect to get. Those numbers are an estimate based on tests developed by the Environmental Protection Agency. But when Consumer Reports ran its own fuel economy tests on 315 cars, the results for many hybrids were surprising.

"Hybrids tend to be very fuel-efficient. But many of those we tested got far fewer miles-per-gallon than their window stickers claim," said Rik Paul, Consumer Reports.

For example, the Ford C-Max hybrid; the EPA says it gets 47 miles-per-gallon overall. But in Consumer Reports' tests, it was 37 miles-per-gallon overall - still good, but about 21 percent less than the EPA estimate.

"We think the problem is that the EPA ratings are based on outdated tests that don't reflect real-world driving conditions for hybrids," said Paul.

Take highway driving, one of the tests the EPA performs on a dynamometer. It tests cars at simulated speeds that average just 48 miles-per-hour -- with a lot of stop and go.

"Hybrids do well in those driving conditions. They can often operate in electric mode without burning any gas," said Paul.

But Consumer Reports tests highway mileage on a highway, at a steady 65 miles-per-hour. Technicians install a fuel meter to measure the amount of gas burned.

"In those conditions, hybrids are constantly running their gas engine, so they burn more gas than they do in the EPA tests," said Paul.

Consumer Reports has discussed its findings with the EPA and the agency says it's considering updating its tests.

Ford says that their C-Max Hybrid customers report a range of fuel economy figures, reinforcing the fact that driving styles, driving conditions and other factors can cause mileage to vary.

Consumer Reports is published by Consumers Union. Both Consumer Reports and Consumers Union are not-for-profit organizations that accept no advertising. Neither has any commercial relationship with any advertiser or sponsor on this site.

(All Consumer Reports Material Copyright 2011. Consumers Union of U.S. Inc. ALL RIGHTS RESERVED.)

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consumer reports, ford, environmental protection agency, 7 on your side, michael finney

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