CALAIS – Traffic was a problem at the border again Monday as Americans returning from their weekend trips to Canada found themselves waiting up to 45 minutes to get through U.S. Customs.

Still, that’s down from last weekend when some tourists complained of two-hour waits.

For the most part, tourists who crossed Monday seemed to take it in stride.

It’s unusual to find long lines at Maine border crossings at this time of year, but that’s what has happened the past two weekends at various crossings along the Maine-New Brunswick line.

Federal officers have been asking to see drivers’ licenses or identification cards. They then enter in the person’s name and other information to a data system. Travelers who encountered an agent with limited typing skills have faced an excruciating wait.

“A long time” is how two Massachusetts women described their 45-minute wait Monday, although they were laughing and smiling.

A family returning to the Washington County town of Alexander from a camping trip in Bayside, New Brunswick, said they were able to make it across in 25 minutes.

“It wasn’t as bad as I thought it would be,” a New Hampshire woman said. She was returning from Prince Edward Island and had heard about the long traffic lines. She estimated her wait to be about 40 minutes.

Last year, crossing on Memorial Day was not a problem.

Back then, officials in Boston had not imposed a stop and request identification rule.

U.S. Customs and Border Protection officials increased their frequency of identification checks last weekend, saying it was not a new policy and that the checking would continue.

Photo identification cards such as a driver’s license, a Maine identification card or passport (current or expired) are acceptable, but documents such as a birth certificate or voter registration card are also acceptable.

The rub comes when border officials have to type information into their computers. Passports are the only identification that can be scanned directly into their system.

When first asked last week about the glut of traffic, Ted Woo, a spokesman for U.S. Customs and Border Protection in Boston, said the practice was not new.

“We are increasing the frequency of checking identification,” he said. “That’s our job: to check who enters the country. This is not a special operation, and it is not a change in policy. It will continue.”

He said the process would become faster when the passport is used for entry. In the meantime, he said, “Expect it to continue.”

Two people who said they regularly cross into Calais from St. Stephen said Monday they did not have to wait long at the Milltown Bridge, near the city’s Industrial Park, because customs officers knew who they were.

But long lines of trucks coming in from Canada at the Ferry Point Bridge seemed to exacerbate the problem at that border crossing. The Ferry Point Bridge connects the two downtowns.

Trucks are required to turn right just before the customs house onto a separate lane where an X-ray machine sits ready to scan their cargo.

However, while the trucks wait to enter the screening machine, the cars behind are blocked from getting to the customs house.

There was almost a rhythm to it on Monday: a truck followed by a long wait and then one or two cars followed by yet another truck.

The long delays have put pressure on federal and state officials to begin construction of a third bridge into Calais. The new bridge would allow traffic to bypass the downtowns in St. Stephen and Calais and would free up the streets for shoppers.