So, pedestrians will soon be able to cross Portage and Main — but how?

Pedestrians haven't been able to cross Winnipeg's most famous intersection since 1979, but that will change in 16 months with the historic first step in a new era.

But exactly how those steps will be taken across Portage Avenue and Main Street has yet to be decided, Mayor Scott Gillingham says.

One option is the traditional setup in which people and vehicles cross in the same direction, while those in perpendicular directions wait at red lights.

Another option, used in many major cities, is a scramble corner: Vehicle traffic in all directions is paused while pedestrians cross to any corner they want.

"The way people will cross the intersection, we'll let our traffic engineers determine that and come forward with the best option," he told CBC Information Radio host Marcy Markusa on Friday, one day after city council voted 11-3 to reopen the intersection by July 1, 2025.

"The reason we're asking for our staff to work very hard and quickly to get it open to pedestrian traffic by the summer of 2025 is to coincide with the change in the transit routes."

A major overhaul of the primary transit network is being undertaken, composed of a series of "spines" along major corridors, with smaller feeder routes to connect them. The aim to to bring that into service by June 2025.

"And so having pedestrians cross at the same time as those transit route changes will just make things much more efficient," Gillingham said.

Something else that could come with the redesign of the transit routes and reopening of Portage and Main is the elimination of heavy truck traffic at the intersection.

"That'll be all part of the transit master plan and yes … the trucking association, we want to make sure that they are consulted when we come to looking at how the transit route changes would or could affect the trucking routes," Gillingham said.

"But that's all part of the preliminary design study. We do know that the changes in the transit routing system will actually make traffic flow through Portage and Main more efficient, and the trucking association will be one of the organizations that's consulted."

Some people have called for the underground concourse — the way pedestrians have had to cross the intersection for the past 45 years — to remain open as a warm option during the winter.

But the expense to repair the membrane protecting the concourse from the weather is exactly why the city has chosen to shut it down, Gillingham said.

"The reason we're here right now is because to maintain the concourse would require $73 million to repair the membrane. And that work would have to be done from on top from in the intersection, which would mean up to five years of traffic delays," he said.

The city has previous estimated that decommissioning the concourse will cost $20 million to $50 million.

"We have asked, as of yesterday … our staff to go and get the definite numbers to really understand the full scope and cost and traffic impacts of decommissioning," Gillingham said.

Asked whether there might be some other future for the concourse, which links all four corners of the city's main office district and the underground Winnipeg Square shopping mall via a roundabout and tunnels, Gillingham simply repeated the cost to replace the protective membrane.

"We're looking at at least $73 million, quite possibly more, because we haven't even considered whether or not the concrete below grade would need to be upgraded," he said.

Earlier this month, Gillingham noted that it's not a one-time cost. The life expectancy of the membrane is 30-40 years.

With inflation factored in, the replacement cost a few decades from now could be more than $200 million.