ABC News' Gio Benitez, Gerry Wagschal and Stephanie Wash report:

In March 2013, Chekia Acres, a single mother of a then 1-year-old son, was driving to work in the middle of Atlanta's afternoon rush hour. She was in the 2001 used Chevy Cavalier she had just bought a few days earlier.

Acres, 32, says it was a happy moment for her.

"I'm excited. I'm driving; I'm singing," she recalls. "I am in the moment and I am loving it."

But her joyride to work was cut short on that busy highway.

"My car literally stops. Here I am driving then all of a sudden, stop," Acres says. "I am hysterical right now because the only thing I am bracing for is someone to hit me."

But someone helped her push her car to the shoulder. Without cash for a tow, however, she was stuck there for five hours.

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"I tried to restart it, nothing is happening," she says.

And then, "Finally, the car just, like magic, cranked back up."

Relieved, Acres drove the car straight home. She turned to the Internet for answers and found a report from Carfax, which sells used car history reports to individuals and businesses.

She was shocked to learn the car she thought had 129,000 miles had more than double the advertised mileage. "It has almost 300,000 miles on it, and I'm livid," she says.

Acres had bought the car for $2,100 at JD's Auto Sales outside Atlanta, after seeing an ad on Craigslist. The car was advertised at 129,000 miles, and was sold to her by salesman Sylvester Egbe, who, Acres says, also confirmed the mileage.

"He's like, 'You can see yourself.' So I looked on the odometer and it read 129,000 miles," she says.

But the Atlanta auction company that had sold the car just days before it landed at JD's Auto Sales told ABC News that the car had more than 290,000 miles at the time of sale.

And although the bill of sale did note that the odometer reading was "not the actual mileage," Acres says she never noticed that line.

As it turns out, Carfax says, there are about a million cars on the road right now with odometers that have been swapped out for ones with fewer miles, or rolled back digitally.

"The amazing truth about odometer rollbacks is that they are actually on the rise," said Carfax spokesman Larry Gamache. "They're typically rolled back between 35 to 50,000 miles and then resold to unsuspecting consumers."

And it's not just old cars that are affected by odometer rollbacks; newer models can be also be easily modified.

"Digital odometers are easier to roll back than the old analog versions," Gamache said.

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So easy that, with some instruction from an expert, ABC News correspondent Gio Benitez was able to roll back a digital odometer in a matter of seconds.

Devices like the one Benitez used can be utilized for legitimate purposes, such as when an odometer breaks, odometer expert John Ingle of Atlanta Speedometers told ABC News. Such devices can be bought by anyone.

Ingle demonstrated to Benitez just how easy it is to change the odometer on a newer car. "So on this 2012 Silverado, we've got nearly 19,000 miles," Benitez notes just before he attempted to change the odometer to 500 miles.

Seconds later, "Success," Benitez says. "Now it says 499 miles. So even less than I programmed it."

Benitez adds, "And this car suddenly got more expensive."

"Yes, very much so." Ingle says. "With the right equipment, you can do anything."

Ingle also says car dealers can easily swap out odometers for newer ones with less mileage on them, as with Acres' 2001 used car.

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Shortly after discovering her car's odometer was changed, Acres called Forest Park, Ga., police on JD's Auto Sales. Police went to the car dealership and fined the shop's owner for "alteration of odometer." JD's Auto Sales took the Chevrolet Cavalier back and refunded Acres for the full purchase price, and later, paid the fine.

Benitez recently paid a visit to Acres' salesman at JD's Auto sales.

As Benitez approached the salesman, Sylvester Egbe, he said, "Sylvester, Gio with 'Good Morning America.' How are you? Let's talk about odometers."

But Egbe had no plans to talk on camera. He had told an ABC News producer by phone the day before, "We advertised it wrong. We changed the odometer because it wasn't working. I should have told her the odometer wasn't working."

As for Acres, she now has a new, reliable car.

"I want everyone to know that you don't have to lie down and take it, you don't have to remain voiceless," Acres said. "You can get your voice back. There is good that will come of it."

One way to check to see if your car may have a potential rollback is by using this free resource from Carfax.com. It checks for potential rollbacks for a specific car using the VIN number. Click here to learn more.

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