WASHINGTON, DC — It could be back to the drawing board for the new U.S. hours of service regulations after a U.S. appeals court Friday ruled them to be illegal because they were “arbitrary and capricious.”

The three-judge panel of the U.S. Court of Appeals for the D.C. Circuit vacated the rule “in its entirety” stating that the government “neglected to consider a statutorily mandated factor of the impact of the rule on the health of drivers.”

The legislation, which went into effect this January 4, has now been sent back to the Federal Motor Carrier Safety Administration (FMCSA) for revision.

The appeals court ruling itself, however, can be appealed to the full appellate court.

In April a group of organizations filed a petition with the court to have the new hours of service regulations introduced by FMCSA overturned. The new regulations represented the first revision of drivers’ hours of service in 65 years.

Under the new HOS rules, drivers’ hours of service on-duty time was reduced from 15 hours to 14 hours in any 24-hour period. But actual driving time was increased one hour from 10 to 11 hours.

In addition to the government’s failure to consider the effect of the rule on drivers’ health, the court panel stated there was “a complete absence of any discussion” of the subject in the ruling, adding that this failure “leaves us with no alternative but to conclude that (the agency) failed to take account of this statutory limit on (its) authority.”

The appeals court also said it had concerns with other parts of the new HOS regulations, including the legality of increasing daily driving hours, its justification for a sleeper-berth exemption and a 34-hour restart. It called the legal justification for such measures “problematic.”

“This is a victory for all truck drivers, including Teamsters,” Teamsters president Jim Hoffa said in a statement. “Working behind the wheel of a truck is hard, and our concern with this set of rules was that they would increase driver fatigue. We know fatigue creates danger on the highways.”

Annette Sandberg, administrator of the FMCSA, said the existing hours-of-service rules for truck drivers would remain in place during a 45-day review period which will follow the court decision.