I remember reading about this project when it was a new idea. I thought it sounded like a smart solution. I guess others didn't, but there are always going to be people who don't agree (sometimes they turn out to be right). But, until it is given a try, no one really knows if it will work. There are unpredictable factors, especially with wild animals and changes to technology as far as vehicles too.

I'm glad its working and especially nice for it to be here in Canada.

Since the 1980s, the Canadian government has allotted more than $400 million to upgrade and twin the four-lane highway, with a quarter of the budget set aside for projects that would reduce wildlife collisions, a growing concern. Parks Canada decided they would use part of that money to fence the entire highway — roughly 180 kilometres — and construct several dozen wildlife crossing structures in hopes of lowering the mortality rate.

In November, Parks Canada marked the 20th anniversary of the completion of the first wildlife overpass in Banff National Park. ... the six overpasses and 38 underpasses that criss-cross the Trans-Canada are today considered a worldwide conservation success story, reducing wildlife collisions by 80 per cent. Delegations from around the world now visit Banff to learn more about their crossing structures in hopes of building similar systems in their home countries, where new roads are cutting through wilderness areas at unprecedented rates.

Roads don’t only imperil wildlife through vehicle collisions; they can fragment habitat and cut off critical migration routes for species. It’s estimated that 25 million kilometres of new road will be built by 2050, the majority in developing countries who have never before had to confront the impact of highways on biodiversity.

Clevenger now has 17 years-worth of data proving the efficacy of the crossings. Among large carnivores, mortality rates are 50 to 100 per cent lower along sections of the highway where overpasses and underpasses exist. In those same sections, mortality rates for elk are almost zero, compared to 100 elk-vehicle collisions per year in the mid-1990s. Clevenger’s research has shown that 11 species of large mammals in Banff have used the structures more than 200,000 times, including unexpected species such as red fox, hoary marmot, boreal toads, wolverines, lynx, garter snakes and beavers.

Black bears and mountain lions prefer to use these shadowy, damp tunnels, says Michel, whereas grizzlies and ungulates prefer the open sightlines offered by the overpasses.

... away from passing motorists’ eyes, lies a grassy oasis. Against the odds, pine trees and wildflowers have taken root here, giving the overpass a fringe of greenery. On the edges, wire fencing provides safe passage for roaming animals.

In 2010, Parks Canada joined forces with CP Rail on a $1 million, five-year joint study to figure out why animals, mainly grizzlies, were dying on the railroad in unprecedented numbers. Their research revealed that a number of factors were drawing animals into the rail corridor, from increased vegetation to an inability to detect oncoming trains, with bears often running toward them, instead of away.

Paraphrased from Canadian Geographic - As Banff’s famed wildlife overpasses turn 20, the world looks to Canada for conservation inspiration