PORTLAND — The U.S. Senate is poised to consider extending a pilot program allowing heavier trucks to keep on rolling on federal highways in Maine and Vermont.

Sens. Susan Collins of Maine and Patrick Leahy of Vermont said Tuesday that they persuaded the Appropriations Committee to include a one-year extension in the Senate spending bill.

Supporters of the program that allows trucks weighing up to 100,000 pounds to use federal highways say it promotes safety by keeping heavy trucks off secondary roads. The program is scheduled to expire on Dec. 18, so the weight limit would go back down to 80,000 pounds.

The provision was missing from a federal spending bill approved by the House last week. Collins and Leahy say the Senate bill comes up for debate this week.