One lane towards Montreal on Mercier Bridge closed indefinitely due to crack: Transport Quebec

A lane on the Honoré-Mercier Bridge heading into Montreal was closed indefinitely Tuesday night after a crack was discovered in one of the bridge’s steel beams, causing major delays for commuters during the Wednesday morning rush hour.

The crack was discovered during maintenance work, prompting the closure of the left lane as a precaution while engineers assess the damage.

“It’s not a very big crack, but when there’s a crack on a steel beam, it needs immediate attention,” said Louis-André Bertrand, a spokesperson for Transports Québec. “We didn’t take any chances and we did close one lane as a preventative measure while we were doing the investigation.”

Bertrand said the lane closure reduces the load on the structure while further analyses are conducted. He added that the crack was not detected during the bridge’s 2025 annual inspection.

Transports Québec says the bridge remains safe for motorists.

“If we have the least worry, we don’t hesitate to close the structure,” Bertrand said. “If it wasn’t deemed safe to drive on the Mercier Bridge, it would not be open right now.”

Engineers are assessing the extent of the damage and determining the best approach to repair the beam. One of the next steps is to determine whether the damaged piece will need to be custom-made or can be replaced with an existing part.

After analyzing data collected over the past 24 hours Transports Québec says only one lane will remain open toward Montreal and with congestion expected during the morning rush hour.

To help ease traffic, westbound Highway 30 tolls will be suspended on weekdays from 5:30 to 9:30 a.m., starting Thursday.

Transportation planning lecturer and Gris Orange consultant president Pierre Barrieau said discovering the crack early could help limit repair costs.

“It’s good that we found it, and also, it’s a lot cheaper to fix when we discover it at the beginning,” Barrieau said.

Depending on the engineers’ assessment, one possible solution could involve temporarily bracing the structure, rebuilding the damaged section and replacing it with an identical piece explained Barrieau.

The closure caused significant congestion Wednesday morning, with some drivers reporting trips taking far longer than usual.

One driver, Jill Zacchia, told CityNews they had been in their car for an hour and a half, with an estimated two-hour travel time, compared with their usual 45-minute commute to the West Island.

“I should’ve checked Google Maps before leaving this morning, me and everyone else apparently,” said Zacchia.

Another couple said they had left home around 7:30 a.m. for a 9:30 a.m. appointment at the Montreal General Hospital and were still waiting in traffic.

“It’s time wasted, money wasted for the company. Everything’s wasted,” said Chris Collin who was stuck trying to get onto the bridge while driving his work’s truck.

Traffic specialist Rick Leckner said the disruption could affect traffic across other South Shore bridges, as commuters look for alternative routes.

“There aren’t that many options that people can use,” Leckner said. “So I’m afraid that it’ll be a situation where people have to use some carpooling and public transit.”

Leckner said he was not surprised by the incident, pointing to the bridge’s age and history of problems.

“Sad, but not surprised. I mean, this bridge has a history of incidents. It’s 92 years old, should be rebuilt to avoid this constant pain,” he said.

However, Leckner noted that rebuilding the bridge would be a complicated process and said he did not expect it to happen anytime soon.

He warned that while traffic conditions may improve after the first morning of the closure, commuters should not expect a significant improvement.

“It’s always worse on the first morning of anything new,” Leckner said. “So hopefully things will settle down a little bit tomorrow, but I don’t think they’ll get much better.”

Transports Québec says the lane will remain closed until engineers determine the necessary repairs and establish a timeline for the work.

Motorists are encouraged to check Québec 511 for updates and consider carpooling, public transit or alternate routes, including the Champlain Bridge.