The new bridge border crossing at Calais, Maine, has lanes designated for transport trucks. (CBC)

A new border bridge opened between St. Stephen, N.B., and Calais, Maine, on Monday, with assurances from border officials that it will end long lineups.

The crossing, which was built mainly to speed up truck crossings over the St. Croix River, sprawls across almost 22 hectares of eastern Maine countryside.

There are three lanes to process commercial trucks with drive-through cargo-scanning technology, as well as six bays, allowing cargo to be unloaded, examined and reloaded quickly.

Private vehicles can choose one of six lanes, and the main building includes an indoor target range so that up to five border patrol officers can get their firearms certifications at once. The two older border crossings between St. Stephen and Calais are also available to private vehicles.

"This facility is built for the future," Steve Farquharson, New England director of field operations for U.S. Customs and Border Protection, said of the new crossing.

Transport trucks are no longer allowed to cross at Milltown Heights or Ferry Point Bridge, which used to be characterized by traffic snarls, with cars and trucks sharing a single lane in each direction.

"I think it will be some years before people experience the kind of wait times or traffic congestions that they experienced at Ferry Point and Milltown," Farquharson said.

Mary Weston, owner of The Dusty Rose antique shop in Calais, said the fear of long lines of traffic drove customers away from businesses on both ends.

"Even sometimes when I want to go over to St. Stephen … you have to pick and choose the time of day and kind of guess when the best time to go is," she said.

"I think it's going to help. I think it will alleviate the backups."