American Trucking Associations is asking the Federal Motor Carrier Safety Administration to push back the start date of the new hours of service rule.
The rule, which ATA and others are contesting in court, is scheduled to take effect July 1.
In a January 25 letter, ATA President and CEO Bill Graves asked the agency to push that date back until three months after the court issues its decision.
The delay will make it easier to manage any changes that the court may require, and to complete personnel training, Graves said in the letter to Administrator Anne Ferro.
At issue is the timing of the suit against the rule. The court has scheduled oral arguments for March 15. It typically takes the court two to three months to rule following arguments, which means the decision could come as late as a month before the start date.
Much of the training for the rule already is under way, but the industry and the enforcement community still will need three months to finish the job once they know what the final rule says, Graves said.
"We recognize that the parties to the pending litigation will differ on what the likely outcome will be, but the undeniable realty is that there is genuine uncertainty until the D.C. Circuit resolves the challenges," Graves wrote.
FMCSA spokesman Duane DeBruyne said the agency is reviewing the letter.
At issue before the U.S. Court of Appeals for the District of Columbia Circuit are petitions by trucking interests to strike four provisions of the rule, and by safety advocates charging that FMCSA erred when it preserved the 34-hour restart and 11-hour driving limit.
ATA and others object to a change in which the 34-hour restart will be limited to once a week, with each restart including two rest periods between 1 a.m. and 5 a.m.
They also object to the requirement that a driver must take a half-hour off if it's been more than eight hours since he took an off-duty or sleeper berth break.
Public Citizen and its allies have told the court that the agency abused its discretion when it preserved the restart and the daily limit. They also say the agency erred in its decision not to eliminate the 11-hour limit on daily driving.
FMCSA, for its part, contends that limits on the 34-hour restart are reasonable, that the productivity savings outweigh the risks of the 11-hour limit, and the 30-minute rest break improves safety.