PHOENIX, Ariz. – A lawsuit charging North America’s 10th largest carrier for underpaying its drivers will be permitted to move forward as a class action suit, an Arizona appeals court has ruled.

The lawsuit against 17,000-truck fleet, Swift Transportation, has been in legal limbo since it was filed in 2004. A motion to certify it as a class action was denied by Arizona Superior Court judge. That ruling was overturned this week by the appeals court.

The suit alleges breach of contract. It accuses Swift of routinely underpaid drivers by rounding out miles driven using a common software program rather than miles actually driven.

Many short-haul miles spent diving in cities were reportedly not accounted for, the suit alleges.

Court documents state that Swift’s former financial manager admitted the software consistently shorted the mileage that drivers actually log by an average of 6 to 10 percent.

The suit could up to 30,000 drivers or more.

According to the court, the class action suit includes "all persons in the United States, including those who were employed by Swift as employee drivers on or after Jan. 30, 1998 or contracted with Swift as owner-operator drivers on or after Jan. 30, 1998, who were compensated by Swift by reference to miles driven."