WASHINGTON -- The nations over-the-road truckers are again facing the prospect of having to adapt to another new hours-of-service regulation as a result of an appeals court decision last month.

The court ruling is the latest reminder of how lucky the motorcoach industry was four years ago when the Federal Motor Carrier Safety Administration decided to listen to pleadings of motorcoach industry trade associations that there should be separate hours-of-service rules for bus and truck drivers.

Since the FMCSA adopted new hours-of-service rules for truckers in April 2003, the agency has not had a moments peace; truckers have been up in the air over the rules they drive by, and lawyers by the score have gotten rich filing lawsuits, both challenging and defending the rules.

In the latest court decision, the U. S. Court of Appeals for the District of Columbia Circuit issued a ruling on a pair of challenges to the current trucking hours-of-service regulations.

In its decision, the court threw out the truckers 11-hour driving time limit and the 34-hour restart.

Significantly, the court ruling was based on procedures followed by the FMCSA in adopting the revised rule and not on the merit of the challenged provisions.

But while truckers may feel they are in a state of limbo with the latest ruling, the reality is that, in the short term anyway, nothing really changes.

The decision does not go into effect until Sept. 14, unless the court orders otherwise. Meanwhile, FMCSA staffers are analyzing the decision and deciding its next steps.

Until the FMCSA takes some sort of official action, truckers are continuing to operate under the 11-hour driving rule and utilizing the 34-hour restart when its needed.

As one trucking association executive said: "The courts ruling impacts the (FMCSA), not truckers."

The ruling marked the third time in three years that an appeals court has been critical of the FMCSA.

In 2004, a panel of the appeals court struck down virtually identical new hours-of-service rules as the ones at issue in the latest decision, saying they were "arbitrary and capricious."

After Congress, at the urging of the Bush administration and the trucking industry, intervened to block enforcement of the 2004 court order, the FMCSA issued the 2005 rules. At the time, the agency said it had addressed the concerns raised by the appeals courts 2004 decision.

A different appeals panel criticized the agency in December 2005 for failing to issue adequate rules for the training of drivers, saying the agency had ignored its own studies on the need for more comprehensive training.

In a regulatory impact analysis accompanying the 2005 hours-of-service rules changes, the agency concluded that the economic costs to the industry of tightening the hours of service rules, as consumer groups had proposed, outweighed the safety benefits.

But the latest court ruling said that that analysis was flawed.

"FMCSA failed to provide an adequate explanation for its decision to adopt the 11-hour daily driving limit," the court said.

The American Trucking Associations, which defended the changes to the rules in the proceeding, said it would ask the court to stay its ruling to give the FMCSA time to provide a better justification of the changes.