West Islanders looking to come downtown any time in the next two years, get ready for some gridlock.

Sunday marked the beginning of a two-year closure of one of the two lanes in the Turcot Interchange connecting Highway 20 East to the new two-lane road that is replacing the Ville Marrie. 

Next month, crews will permanently close four eastbound lanes of the Ville Marie Expressway (Highway 720).

That's also when crews will begin three or four months of weekend closures of the Turcot ramps from the 20 East to what will replace the 720, and of the 15 South toward downtown.

Transport Quebec spokespeople said last week they expect that traffic jams will routinely be four kilometres long, from the Turcot back to the Ville St. Pierre Interchange.

The destruction of the eastbound 720 is because crews are building a new road, parallel to the Ville Marie, called Route 136.

Route 136 will connect the Turcot Interchange to the Ville Marie Tunnel, and was originally scheduled to be opened in November 2016. 

"In mid-November all traffic that is going downtown will be diverted on those two lanes," said Sylvie Gervais of the KPH Turcot construction consortium. 

The STM is doing what it can to accommodate people who will use public transit, and will add an extra train to the Green line. 

It has also added many extra buses to routes going through the area. 

St. Jacques St. Bridge

Meanwhile construction crews will need to shut down all northbound lanes on Highway 15 for at least one more weekend to complete the dismantling of the St. Jacques St. Bridge.

The northbound lanes through the Turcot were closed over Thanksgiving weekend but crews were not able to finish the work that began in July. 

In order to finish the task, all northbound lanes of Highway 15 through the Turcot, including the connections between the Ville Marie Expressway and the Decarie Expressway, will be closed this weekend, from the evening of Friday Oct. 14 until early Monday Oct. 17. 

Those trying to head north should avoid the Turcot area entirely. Their best option may be either Highway 25 or Highway 13.

Drivers heading south on Highway 15 and wishing to get downtown will have to detour several kilometres to the west and loop around at Angrignon Blvd.