By Jim Donovan

PHILADELPHIA (CBS) – When buying a new car, truck or SUV, how much consideration do you give to the mileage claims? Would you be more likely to buy a vehicle that promised that you’d get more miles per gallon?

At least one driver found that what the mileage promised may not be what you actually get. She took her car maker to court, and she won. Honda was ordered to pay the plaintiff for misleading her about gas mileage.

To many, Heather Peters’ case seemed like just another frivolous lawsuit.

The complaint? Her 2006 hybrid failed to get the 50 miles per gallon advertised by Honda.

Peters took on the giant automaker in small claims court, dropping out of a proposed class action settlement that offered dissatisfied customers a couple hundred dollars.

Peters, a former attorney, argued her own case.

“I decided to go it alone, Judge Judy-style,” said Peters.

A superior court commissioner sided with Peters, awarding her nearly $10,000 and citing Honda for misleading language that promised “plenty of horsepower while still sipping fuel.”

Honda will appeal the verdict, because it says fuel economy estimates are determined by the Environmental Protection Agency–not the automaker.

“It starts as a $10,000 judgment, but this could end up as a billion dollar bleed if everyone opts out of a class-action and goes instead through small claims court,” said law professor Laurie Levenson.

Now, Peters is urging 200,000 other plaintiffs to sue.

She’s even set up a website called Don’tSettleWithHonda.org.

“It’s justice in a very small place, but sometimes, the little guy wins,” said Peters.

Last night, Honda issued a lengthy statement insisting that the Honda Civic hybrid has the capability to achieve 50 miles per gallon or more “in real world driving conditions.”

For more information on how fuel economy is calculated, click here.