How long will the open road last?

Opinions divided on how many trucks will actually be diverted from Montreal’s clogged roads, and for how long

The view out the windshield: traffic relief. Out the rear window: new traffic to fill up newly cleared lanes.

Highway 30, which opens Saturday, is expected to reduce traffic on Montreal Island but it’s unclear how long the open road will last.

The new roadway will link Châteauguay and VaudreuilDorion and will include a toll bridge between Salaberry-deValleyfield and Les Cèdres, allowing vehicles to bypass Montreal.

But even as it was planning the $1.5-billion South Shore ring road, Transport Quebec was skeptical about whether it would remove heavy trucks from Montreal highways.

In fact, Highway 30 is expected to have little impact on truck traffic on Montreal highways, according a 2005 Transport Quebec study, obtained by The Gazette via an access-to-information request.

At most, Highway 30 will remove about 3,500 heavy trucks daily from highways 20 and 40, says the study, which focused on the new highway’s impact on trucks doing inter-city runs.

“Assuming all 3,500 trucks would be subtracted from Highway 40, the effect on traffic of the highway … will be relatively low,” the study found.

That’s because 3,500 represents a tiny portion of the 175,000 vehicles using Highway 40. In addition, the demand is actually two times greater than that highway’s capacity.

That means “any improvement in the level of service on Highway 40 would be shortlived.”

“It would quickly attract users that currently use other routes to save time but for whom Highway 40 is the optimal route.”

Predicting highway usage “is not an exact science” and Transport Quebec is reluctant to predict how many trucks will be removed from Montreal, department official Sandra Sultana said.

“It will have an effect on Montreal, there will surely be vehicles that will want to bypass the island, but we can’t say how many,” she added.

Even the total number of vehicles (trucks and cars) expected to use Highway 30 remains anyone’s guess.

There is a wide discrepancy between official traffic estimates for the toll bridge.

Transport Quebec says its estimate, calculated several years ago, suggests 12,000 vehicles daily by the end of the first year of operation.

But Nouvelle Autoroute 30, the private consortium that built and will maintain and operate the highway, figures about 34,000 vehicles will use the bridge daily, said Denis Léonard, the consortium’s chief executive.

Transport Quebec’s figures are “much more conservative,” Sultana said. “We did our estimates when there was no toll infrastructure in place. We didn’t know how users would react.”

Road tolls were abolished in the Montreal region in 1990, when the Champlain Bridge stopped charging a fee.

They returned in May 2011, when the Highway 25 Montreal-Laval bridge opened.

“Now, with the 25, we see there’s an interest (in toll roads) so we can assume usage will be higher than we calculated,” Sultana said.

Based on what he has been hearing from trucking companies, Marc Cadieux, chief executive of the Association du camionnage du Québec, expects Highway 30 to siphon many trucks from Montreal.

He said the 2005 study could be off-target because it was conducted when “there wasn’t as much roadwork, it wasn’t as chaotic as it is now.”

That includes ongoing, disruptive repairs to the Mercier and Champlain bridges and Turcot Interchange. And, he added, things will worsen once work begins on the new Turcot and new Champlain.

Highway 30 is expected to be used by truckers who now use Highway 20 and the Mercier or Champlain bridges on trips between Ontario and the U.S., and by those who now use Highway 40 between Ontario and eastern Quebec.

That will “relieve local traffic, meaning trucks making deliveries on Montreal Island won’t be stuck behind ones that have no business being in Montreal,” Cadieux said.

Trucking companies will “save time and fuel, there will be less stress and fatigue and fewer accidents,” he added.

Highway 30 should cut traf- fic on the Mercier, Champlain and Jacques Cartier bridges, though the bridges’ federal operator does not have an estimate on the traffic impact, said Jean-Vincent Lacroix of Jacques Cartier and Champlain Bridges Inc.

The new highway will offer an alternative to cars and trucks from the South Shore heading for Ottawa, Gatineau or parts west, he noted. They’ll be able to reach des- tinations without crossing the West Island or taking federal bridges, Lacroix added.

Even environmental groups that normally resist new highways saw the need for a ring road to alleviate traffic on the 20 and the 40 and the Turcot in Montreal.

“But if you want to have a positive environmental effect, you also have to put more reserved bus lanes in place so public transit benefits, too,” said Daniel Bouchard of the Conseil régional de l’environnement de Montréal, a coalition.

“Whenever you build a highway, it’s clear you’re encouraging car use,” he added.

“Nobody has ever reduced traffic or pollution by building a highway — it may be alleviate traffic temporarily but it will eventually just be filled up by new traffic.”

In addition to spurring car use, Highway 30 will encourage South Shore urban sprawl, Bouchard added. To offset those negative effects of Highway 30, he said, Quebec should make transit more efficient by expanding the network of reserved bus lanes on the South Shore and on Montreal Island.