London drivers can kill with kindness — and the city plans a controversial campaign to fight back.

When drivers approach construction zones and two lanes are reduced to one, most London drivers try to merge early, well before the closing lane ends.

That may seem like a very Canadian approach to road-sharing, but those polite intentions backfire.

Traffic research collected since 2004 generally has shown that when drivers merge early, overall traffic slows and the risk of collisions increases, said Shane Maguire, who looks after traffic control for city hall.

The better way to merge is for vehicles in the closing lane to use it right until the end, where drivers from that lane and the open lane should alternate moving ahead, a practice some call zipper merging.

But while the science is pretty clear, convincing Londoners to do the right thing won’t be so easy.

City officials gave a teaser of their plans at a Canada 150 celebration but drivers were skeptical.

“People had a good chuckle,” Maguire said. “The feeling was that those who use (the merging lane) were cheating.”

“It’s a mindset to get over,” Maguire said, adding “we are Canadians and we are polite to a fault. But we are better off merging (late) at the site of construction . . . You’re using the space more efficiently.”

If drivers wait to merge where one lane ends, traffic will move past construction efficiently because all available lane space will be used, he said.

Such a change will not only reduce traffic jams, collisions as well, he said. That’s because dangers are created when most motorists try to merge early:

— As the queue of traffic in the open lane grows far longer, the risk of rear-end collisions increases.

— The few remaining vehicles in the closing lane travel faster than those in the long queue in the open lane, a speed difference that can cause crashes.

— Since every driver may try to merge at a different point, rather than just where a lane closes, the risk of crashes from unpredictable driving goes up.

The London campaign will have two fronts — one roadside, the other online.

Signs that show the correct way to merge will go up at a construction site not yet selected. The city will also launch an online campaign to educate motorists that will include posters and a video, Maguire said.

“It’s something we plan to implement this year,” he said. “Initially, the plan was to go out a little earlier but the plan was delayed.”

While city officials will first focus the campaign on construction zones, they will later expand it to include mergers that are the result of the way roads are designed, since the same principles apply, Maguire said.

The push to change how London drivers merge is part of a broader city hall effort, called London Vision Zero, to reduce serious collisions and traffic deaths on streets.

Other components of the project include recently-installed red-light cameras, the creation of 83 crosswalks this year and last year and a renewed campaign against speeding on residential streets.

As London becomes the latest North American city to push drivers to use zipper merging, experience elsewhere shows bad driving habits don’t die easily.

In June, Windsor placed zipper-merge signs on the E. C. Row Expressway to convince drivers to adopt the superior merging method, but officials there noted a similar effort in 2009 failed.

“(The 2009 campaign) was not that successful, to be quite honest. It was just the driving habits of the people — trying to break them was problematic,” Dwayne Dawson, Windsor’s director of operations, has said.

A key in London will be to convince drivers that where one lane ends, vehicles from that lane and the open land should alternate, much as vehicles do at a four-way stop. “You’re not hurting yourself by letting the other person go,” Maguire said.

It was a 2004 study by the Virginia Transportation Research Council that helped to popularize the notion that zipper merging helps with the flow of traffic, and many studies since have supported that notion.

Zipper merging gained a greater foothold in Canada after the Alberta Motor Association endorsed it.