NEW WESTMINSTER, B.C. - A major construction project expected to affect thousands of drivers who use the Pattullo Bridge is getting underway Tuesday night, with northbound lanes scheduled to be closed during overnight hours most nights until Nov. 4.

The closures run from 10 p.m. until 5 a.m. and only affect the two northbound lanes. With the exception of Halloween night (Thursday, Oct. 31) the closures run from Sunday night to Friday morning, with the bridge open in both directions on Friday nights and Saturdays.

According to TransLink, which operates the bridge, the closures are allowing safety upgrades on the bridge. Those upgrades include the installation of seismic activity and wind warning sensors, bridge closure devices, and advanced warning lights and sirens.

"If you do see an extreme weather event, it will close the bridge on either side," Ben Murphy with TransLink told CTV News. "So there are boom gates that come down, there's flashing lights, that will prevent vehicles and pedestrians form entering the bridge if we were to see a really extreme weather event."

TransLink could not say how high winds would have to be to activate the new system, and could not provide renderings of what it will look like.

The system, which is costing $5.5 million, would also work in the case of an earthquake.

It’s expected to be operational by the end of the year.

TransLink is urging drivers who may be affected by the closures to take the Alex Fraser or Port Mann bridges instead. The N19 bus will be re-routed over the Queensborough Bridge, which is expected to tack another 30 minutes onto travel time for passengers.

"There will be some inconvenience for people who do use the bridge overnight, but this is essential work," Murphy said. "We do need to get in there and get it done."

Cyclists, pedestrians and emergency vehicles will be able to use the bridge in both directions during the closures.

The Pattullo has been subject of multiple lane closures in the past as TransLink tries to keep the aging span operational until it can be replaced. There are both seismic and structural concerns on the bridge, which opened in 1937.

In 2018, the province announced plans to build a four-lane replacement bridge at a cost of $1.37-billion with completion expected in 2023.

At the time, the province said construction was set to begin in 2019, but the Ministry of Transportation told CTV News Tuesday major work is now expected to begin next year.

"Construction site preparation and investigative works are underway on the Surrey side of the bridge," the ministry said in a statement. "The project is currently in procurement phase, and a preferred proponent will be selected this fall. Major work on the project will begin in 2020."

The province says the replacement bridge is still set to open in 2023.

