A Senate hearing on truck safety was dominated by the ongoing struggle over the 34-hour restart provision of the hours of service rule.

Anne Ferro, in what was probably her last congressional testimony before she steps down as chief of the Federal Motor Carrier Safety Administration, defended the restart.

The provision, which requires drivers to take two periods off between 1 a.m. and 5 a.m. during their 34-hour restart and limits use of the restart to once a week, puts common-sense limits on the most extreme driving schedules, Ferro said.

“The rule will assist in saving 400 lives a year,” she told the Senate Commerce Committee Tuesday. “We have seen no documentation that it harms trucking companies. Tonnage is at an all-time high … and trucking profitability is on par for a record this year.”

And there is nothing in the rule that limits carriers’ ability to set their schedules as they see fit, she told Sen. Cory Booker, D-N.J.

Sens. Kelly Ayotte, R-N.H., and Roy Blunt, R-Mo., pressed the case for suspending the provision while FMCSA studies its impact on safety.

Ayotte said she wants more information about the safety impact of putting more trucks on the road early in the morning because of the rule.

“To delay the rule while we understand that seems to me seems logical,” Ayotte said. She also said that her shipper constituents tell her the rule is increasing costs and adding risk.

She and Blunt are in favor of an amendment by Sen. Susan Collins, R-Maine, to a Transportation Department appropriations bill that would suspend the restart while FMCSA studies its impact.

Also pending in that bill is another amendment by Sen. Cory Booker, D-N.J., that would keep the restart in place while the study goes forward.

The issue is not resolved because the appropriations bill is stalled, but Blunt hinted that proponents of the suspension may be looking for another vehicle. “We’ll see if (the amendment) stays (in the appropriations bill),” he said.

Ferro told Ayotte that the agency estimates the provision is putting about 250,000 more trucks on the road, “a drop in the bucket compared to the 10 million” already on the road.

She also said that the provision has been in effect for a year and to roll it back would have an impact on safety.

Seconding this point was Major David Palmer of the Texas Department of Public Safety. “The HOS regulations are first and foremost safety regulations, not efficiency or productivity regulations,” Palmer said in his testimony.

“Temporarily suspending enforcement of a regulation not only takes inspection personnel away from their routine enforcement duties … it also requires expenditure of unplanned resources,” he said.

“We would prefer not to have to deal with retraining for something that could be temporary.”

Dave Osiecki, executive vice president and chief of national advocacy for American Trucking Associations, said that while ATA supports five of the six main components of the hours of service rule, it wants the restart provision suspended pending the study.

There is a safety cost to putting more trucks on the road early in the day, he said. “There’s an offset there, and the question is, what is that offset?”

Sen. Richard Blumenthal, D-Conn., chairman of the Surface Transportation Subcommittee, said he wants to keep the restart provision in place while the study is under way.

“I strongly caution against discarding years of careful analysis,” he said “We should allow the rules to work before considering changes.”