A court heard oral arguments Friday in a legal move attempting to stop the Federal Motor Carrier Safety Administration’s plan to implement revised hours-of-service regulations, but there is no indication if the three-judge panel in the District of Columbia will issue a decision before the new rules take effect.

The American Trucking Associations claimed the changes, scheduled to go into effect July 1, would put onerous restrictions on drivers’ ability to effectively manage their schedules. At issue are the new rules limiting the use of the 34-hour restart period to once every seven days, as well as inflexibly mandating 30-minute off-duty breaks during the workday after no more than eight hours of driving. ATA contended that these changes were not supported by the data available and should be rejected.

“The existing rules have a proven track record, and the agency’s purported reasons for tinkering with them were baseless,” said ATA General Counsel Prasad Sharma. “We’re hopeful the judges will see through the agency’s mere pleas for deference and after-the-fact explanations for a rule that was agenda-driven rather than evidence-based.”

A Justice Department attorney representing FMCSA and the U.S. Transportation Department claimed otherwise, saying the regulations are based in sound science.

FMCSA recently denied a request by the ATA to delay the start of the new rules from its scheduled July 1 implementation, drawing a harsh rebuke from the group.

ATA is being supported by a broad spectrum of groups in the matter, including the Owner-Operator Independent Drivers Association, the National Industrial Transportation League, the National Shipper’s Strategic Transportation Council and the Truckload Carriers Association.

Separately, a coalition of outside advocacy groups challenged FMCSA’s retention of the 11th hour of driving and the existence of the restart at all. They include Public Citizen, Advocates for Highway and Auto Safety and the Truck Safety Coalition. Their arguments were also heard in court.

There is no deadline for the court to rule, but both sides are hoping for a quick decision before the scheduled July 1 implementation.