MONTREAL - Roadwork will block major arteries in Montreal this weekend.

Here’s what’s closed:

Mercier Bridge

Only one lane will be open in each direction on the Mercier Bridge between Saturday at 11 p.m. and Monday at 5 a.m.

Highway 20

From Friday at midnight until Monday at 5 a.m., access to the Highway 20 will be restricted:

The Highway 20 eastbound (towards downtown) will be closed between the exit for the Mercier Bridge and the Turcot interchange.

The Highway 20 westbound (towards the West Island) will be reduced to one lane between Angrignon Blvd. and the Saint-Pierre interchange.

St-Pierre interchange closure Oct. 25-28.

Turcot interchange

Several exits are closed on the Turcot interchange between Friday at midnight until Monday at 5 a.m.

Turcot closures, Oct. 25-28.

The exit from the Highway 720 westbound to the Highway 20 westbound will be closed.

The exit from the Highway 15 northbound to the Highway 20 westbound will be closed.

On the Highway 720 eastbound, the exit for Atwater Ave. will be closed.

Champlain Bridge

Some access to the Champlain Bridge will be affected this weekend between Friday at 10 p.m. and Monday at 5 a.m.

One lane will be closed on the Highway 10 East on the approach to the Champlain Bridge.

The Highway 15 North will be closed between the exit for Highway 10 and Boul. De la Verendrye. This closure begins Friday at midnight and ends Monday at 5 a.m.

The entrance onto Gaetan-Laberge Blvd. will be inaccessible from Highway 15 North.

One lane will be restricted between the Highway 15 South between Gaetan-Laberge Blvd. and Nun's Island.

The exit for Nun’s Island, heading south on the Highway 15, will be closed. So will the entrance to the Highway 15 South from the island.

Starting Saturday at 10 p.m. and ending Monday at 2 p.m. the Highway 15 South will be inaccessible from Gaetan-Laberge Blvd.

Highway 10

The Highway 10 East, from the Champlain Bridge to the Highway 132, will be reduced from three lanes to one starting Friday at 10 p.m. and ending Monday at 5 a.m.