AUGUSTA — Maine’s two U.S. senators said Tuesday that they have introduced legislation that would raise truck weight limits on federal highways as a way to help truckers cope with the high cost of diesel fuel.

Republican Sens. Susan Collins and Olympia Snowe proposed a two-year pilot program to allow rigs carrying up to 100,000 pounds to travel on the federal interstate system whenever diesel prices reach $3.50 a gallon.

The price of diesel fuel averaged $4.85 in Maine on Tuesday, according to the AAA.

Collins said the higher weight limit would allow for more cargo in each truck and eliminate the need for drivers to move onto local roads that require more fuel and extended periods of idling.

“The rapidly growing price of diesel is putting an increasing strain on our trucking industry, which is the cornerstone of our economy,” Collins told a news conference outside the headquarters of the Maine Motor Transport Association.

“Current laws that force trucks carrying more than 80,000 pounds off the federal interstate system, and onto smaller, two-lane roads, simply do not make sense. This legislation would lessen the fuel cost burden on truckers by putting these trucks back on the federal interstate where they belong,” she said.

The bill has the support of the Maine Department of Transportation, which conducted a study four years ago that showed higher weight limits would be beneficial.

“Our studies showed that it would be safer, save us money and also would be more energy efficient in terms of delivery of goods,” Commissioner David Cole said.

Cole said trucks are now forced to travel on secondary roads that take them past villages, schools and neighborhoods.

“It just makes common sense to put these trucks on the interstate, which is where they’d like to be,” he said.

Under current law, trucks weighing 100,000 pounds are allowed to travel on the portion of Interstate 95 designated as the Maine Turnpike. But truckers headed north must leave I-95 at Augusta, even though the limited-access, four-lane highway continues for about another 200 miles to Houlton.

The proposed legislation would require the Government Accountability Office to complete a report about safety and other concerns at the completion of the pilot program.