The success of the country's commercial transportation network hinges on the Nipigon River Bridge, a vulnerability exposed when the northern Ontario crossing broke Sunday and severed the trucking route between Eastern and Western Canada.

Roughly 1,300 trucks cross over that stretch of the Trans-Canada Highway each day, carrying $100 million worth of food, mail, machinery and other goods, according to 2012 figures provided by the Canadian Trucking Alliance.

"Every truck that drives across Canada, will go across that bridge," Nipigon Mayor Richard Harvey said Monday. "The country has been cut in half … and from that perspective, it's an issue of national importance."

Police initially shut the bridge to traffic Sunday evening after the crossing's west side began to pull away from its abutment, lifting the deck by about 60 centimetres.

Officials were unable to say how long it might take to repair the bridge, but one lane was opened on Monday around 11 a.m. and passenger vehicles and regular-sized transport trucks were being escorted across. Oversized trucks are not being allowed to cross the bridge.

There are rural logging roads in the area, about 100 kilometres northeast of Thunder Bay, Ont., but those don't have the infrastructure to support most commercial or passenger vehicles. There's no alternative to the bridge, other than taking a detour through the United States.

Border security

That detour has proven increasingly difficult as security regulations increased after the Sept. 11 attacks, resulting in the majority of domestic shipments driving through Canada, the chief executive officer of the Canadian Trucking Alliance said Monday.

Before that time, trucks could travel through the U.S. and be considered an "in-transit shipment" — essentially cargo that was just moving through the country — and not be scrutinized in the way goods staying in the country would be, David Bradley said.

"But since 9/11, the U.S. security officials have … treated those in-transit movements as international shipments — and with that comes a much greater requirement for data and other kinds of rules," Bradley said. "So that basically choked off that outlet."

He said the two countries began working on a pilot project to allow about nine trucking firms to resume in-transit shipping, but that has yet to come to fruition.

The Canada Border Services Agency said in an email that it is working with the trucking industry "to develop temporary measures to address the issue." The agency didn't offer any specifics.

The Nipigon River Bridge, about 100 kilometres northeast of Thunder Bay, is the only route through northern Ontario to the eastern and western parts of the country. (Google Maps)

Another roadblock to sending commercial traffic through the U.S. would be the different weight restrictions the countries have on their highways.

Most Canadian highways support a combined vehicle and cargo weight of up to 46 tonnes, six tonnes heavier than what's allowed in the U.S. for three-axle trailers, said Barry Prentice, a business professor at the University of Manitoba.

That's largely because Canadian winters will erode the highways before heavy traffic will, Prentice said, so domestic trucks are allowed to transport more cargo, which makes it cheaper to ship goods.

"We take our transportation system and infrastructure for granted until something goes wrong, so this is kind of a wake-up call," he said Monday. "Our transportation infrastructure is so key to our economy, whether it's road or rail or air."

The stretch of the Trans-Canada Highway along the Nipigon River and from Kenora, Ont., to Winnipeg are the only two sections that Prentice knows of that could bottleneck because there are no alternate routes.

It's something that makes their maintenance especially critical to the economy, he said.

But the shifting nature of the transportation industry could ease some the pressure on those critical points, Prentice said, as there has been an uptick in train cargo, which then gets picked up by trucks in either Winnipeg or Toronto.

Emergency plans

The $106-million expansion of the Nipigon Bridge, which has been ongoing, was slated to finish in 2017. It was also touted as making the country's shipping route less vulnerable, the community's mayor said, as it would boost the two-lane crossing to four lanes.

Harvey said the town has three different emergency management plans, depending on the season, to redirect passenger and commercial traffic in cases when the bridge is blocked or broken.

One of those possibilities includes reinforcing some of the logging roads so they could support traffic, but Harvey said the exact details are being kept secret.

"The last thing we want right now is people to start trying to go around that bridge."