PORTLAND, Maine — Backups along Interstate 95 on the Piscataqua River Bridge between Maine and New Hampshire have become a routine problem in the summer.

It’s a problem that Maine Turnpike Authority interim director Peter Mills says he aims to address.

“The issue with the Piscataqua bridge is one of the largest strategic challenges for the state,” Mills said in a telephone interview Wednesday.

Southbound motorists on the Maine Turnpike found themselves in a 19-mile-long traffic jam after the Labor Day weekend.

“We had just an unbelievable amount of traffic,” said Mills. “Everybody blamed the tolls. It’s certainly an issue, but it’s the bridge” that is the biggest problem

The issue, Mills said, is the design of the span itself. Because of the incline, intimidating height and spectacular views from the bridge, motorists tend to slow down.

Christopher Waszczuk, administrator of the New Hampshire Bureau of Turnpikes, agrees with Mills that the Piscataqua River Bridge slows traffic.

Another factor is that the amount of traffic using the bridge has dramatically increased since its opening nearly 40 years ago.

“Traffic has gone up 2½-fold of what it was in 1972 on the weekends,” said Mills. But the bridge is fine on a day-to-day basis, he said. “It’s doing a great job.”

Mills said the traffic jams mostly happen during the weekends of warmer months.

“It’s purely a summertime phenomenon,” he said. “People are trying to escape the Boston heat.”

He suggested one way to avoid the snarls is to drive on a different day.

“I hate to say this, but stay over Sunday night and leave Monday and they’re in the clear,” said Mills.

He hopes that will be only a temporary solution because he has the bridge and its two neighboring spans on the top of his priority list for repair work.

In addition to the Piscataqua River Bridge, the Memorial Bridge and the Sarah Mildred Long Bridge also cross the Piscataqua River.

The Memorial Bridge, which opened in 1923, is now closed. The Sarah Mildred Long Bridge, which opened in 1943, is not far away from having trucks restricted from crossing because of its age.

“We’ll be rebuilding these three bridges in a series starting with the oldest one,” said Mills.

Mills said he hopes to have the Memorial Bridge replaced before the Sarah Mildred Long Bridge needs to be addressed.

The Piscataqua River Bridge will need resurfacing in about 16 years.

The projected cost of rebuilding the deck is $40 million to $50 million.

“We’re concerned about how to fund this” even now, Mills said.

For now, there’s no easy and inexpensive solution to the traffic jams.

One possible option is to eliminate breakdown lanes on the Piscataqua River Bridge, Mills said.

“There’s a breakdown lane on each side. You could restripe it and make it four lanes that are only 11 feet wide, which is fine for cars and passable for trucks, but it could be a challenge and you would have no allowance for a broken-down car,” said Mills.

Mills said he will hold discussions soon with the New Hampshire and Maine departments of transportation. He said they all agree that the traffic jams are an issue that needs addressing soon.

The Associated Press contributed to this story.