A class action suit against Swift Transportation over mileage pay is expected to proceed after the Arizona Supreme Court denied the truckload carrier’s petition for review.

On Aug. 31, the higher court declined to review a trial court’s decision to certify a broad class action. Last November, a Maricopa County trial court entered an order certifying a class of owner-operators and expanded the class to include employee drivers.

The truckers allege the Arizona-based company insufficiently paid drivers for miles driven using a database that shorts drivers a significant percentage of mileage. The class action potentially could affect anyone who drove for Swift from 1998 to the present.

Swift did not respond to a request for comment on the case, which has endured eight years of legal wrangling. However, it stated in an Aug. 9 Securities and Exchange Commission filing that it believes the class is improperly certified and “that the claims raised have no merit or are subject to mandatory arbitration.”

The plaintiffs’ Washington, D.C.-based law firm, Hagens Berman, has said Swift breached contract and the implied covenant of good faith because of its alleged failure to pay for all miles driven.