HAGERSTOWN, Md. — The trucking industry scored a victory this week when Republican lawmakers effectively blocked Obama administration safety rules aimed at keeping tired truckers off the highway. But there’s more coming down the road.

The American Trucking Associations is vowing to come back next month, when both the White House and Congress will be under Republican control, and seek to block state laws that require additional rest breaks for truckers beyond what federal rules require. The association says there should be one uniform national rule on work hours for interstate truckers.

The trucking industry’s latest win has sparked concern among safety advocates that it may be just the start of a broad rollback of transportation safety regulations once there’s no longer a Democratic president to check the tendency of Republican lawmakers to side with industry.

“Unfortunately, it’s going to be an open season on safety in this coming Congress,” said Jim Hall, who was chairman of the National Transportation Safety Board during the Clinton administration.

Besides pre-empting state laws on rest breaks, it’s also likely that shippers and some segments of the trucking industry will push for long-sought goals of increasing the weight limit on trucks to more than 90,000 pounds and increasing the length of individual trailers from 28 feet to 33 feet, safety advocates said.

“It’s going to be very tough because the companies really care about the cost. They don’t care about the safety no matter what they say,” said safety advocate Joan Claybrook.

The provision Republicans added to a must-pass government spending bill this week suspends regulations issued by the Obama administration requiring truckers to take two nights off to rest after a workweek of up to 75 hours.

Truckers are required to take a 35-hour break after at the end of a workweek. But the trucking industry objected to requirements that the 35 hours include two periods from 1 a.m. to 5 a.m. Sleep scientists say rest during the early morning hours is critical for people to feel refreshed. The suspension means truckers can head out on the road again during those hours if the 35-hour break has elapsed.

Another regulation that prevents truckers from working 75 hours, followed by a 35-hour break, and then resume driving again in the same week was also suspended.