Why did the moose cross the highway? Because we built it an overpass

Why did the moose cross the highway? Because we built it an overpass

A recent study from Banff National Park concludes that DIALOG-designed animal overpasses crossing the Trans-Canada highway are working. It also indicates animals just might have preferences in architecture and design.

Published in the scientific journal Conservation Biology, the study examines the impacts of fracturing animal habitats. According to research gathered starting in 2006, the overpasses, including those designed by DIALOG, are being used and are helping keep bear populations strong in the park, despite the fact that a major highway divides their habitat.

“This is a landmark study because it’s the first time anyone has done extensive genetic sampling to address unanswered questions about the use of highway crossings by bears,” says research scientist Tony Clevenger. “We knew that bears used the crossings, we just didn’t know how many, what percentage of each species’ population uses them, whether there is a preference by males or females to use crossings, and if there was a gender or species preference for overpasses or underpasses.”

The news that the overpasses are so well used is particularly satisfying for the team that helped design them.

“We worked on the design of the first two bridges and then helped with the process and review on the next four,” says lead engineer and DIALOG principal Dr. Jim Montgomery. “Nobody really knew if they were going to meet expectations, but it seems safe to say they are working very well. It’s satisfying to apply our engineering and design expertise to a challenge like this and see the solution make such a difference.”

More than three million visitors travel through Banff National Park each year. Nearly 18,000 cars a day drive the highway crossing the park and a high number of collisions before the bridges were built had officials looking for safe, viable solutions.

“You have people travelling upwards of 110 km in all kinds of conditions with very big animals coming out to cross the highway without notice; it can be very dangerous,” says Montgomery. “The overpasses are designed to attract and usher the animals safely across the highway in a way that does not disrupt natural behaviour. At the same time they definitely help keep motorists safer.”

Another piece of the study set to be released later this year breaks down gene flow between bear populations in the Banff ecosystem. Speculation is that the data will gauge how well the bridges perform in allowing different bears to find mates.

The precast concrete arch segments for the first two overpasses were manufactured and erected by Lafarge for a construction cost of $4 M in 1997.

Comments (1)

  1. Ralph Himsl

    The sight of the passageways (over and under) the highway gives encouragement and hope to us travelers. I like the aesthetic qualities of the overpasses. I like too the idea that we humans might behave in such an enlightened manner. The explanation given in this video satisfied me. Good for you.

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