Transportation leaders in the House are asking the Government Accountability Office to review two studies used by the Federal Motor Carrier Safety Administration in its hours of service rule.

Reps. Bill Shuster, R-Pa., and Tom Petri, R-Wisc., are reacting to objections by some in the trucking industry to the 34-hour restart provision of the rule.

“Concerns have been raised that these regulatory changes may have been enacted without proper data or analysis,” said Shuster in a statement.

Petri added: “We need to make sure the requirements are based on sound facts and actually improve safety rather than just overwhelm the industry with another onerous regulation.”

The provision requires drivers to take off two periods between 1 a.m. and 5 a.m. during their 34-hour restart, and limits the restart to once a week. The agency says this improves safety by giving drivers more rest, but some carriers object, arguing that it reduces their productivity and puts drivers onto the road during morning rush hour, without improving safety.

In a letter to GAO, the congressmen asked for evaluations of two studies FMCSA used to write the provision.

The most recent study, a field test of earlier lab work, proved the benefit of the restart provision, the agency has said.

Shuster and Petri asked GAO to see if this study collected the proper data and if the drivers were representative of the industry. They also want to know if the study looked at the safety impact of having more trucks on the road during morning hours, and if the driver groupings were appropriate.

The second study was part of the agency Regulatory Impact Analysis in the rule itself. Shuster and Petri asked for GAO’s take on the validity of assumptions, data and methodologies in the study.

American Trucking Associations applauded the request.

“We appreciate Chairmen Shuster and Petri’s leadership on this important truck safety and operational issue,” said ATA Executive Vice President Dave Osiecki in a statement. “ATA looks forward to GAO’s evaluation of the studies at issue.”

In another development on the Senate side of Congress, Sen. James Inhofe, R-Okla., has asked GAO to look into state practices on Commercial Driver License testing.

Some states are experiencing significant testing delays, which slows down the hiring process for would-be drivers who can’t get their CDL in good time. Inhofe has asked GAO to assess the situation on a state-by-state basis and determine the economic impact of the delays.