The Hidden Engineering of Wildlife Crossings

Bridges for animals

Errata: Several people have pointed out crossings that are larger than the Wallis Annenberg bridge will be. I should have said "largest of its kind," meaning true bridges.

The reasons we’re willing to invest so much into wildlife crossings aren’t as obvious as you might think, and there are some really interesting technical challenges when you’re designing infrastructure for animals.

Practical Engineering is a YouTube channel about infrastructure and the human-made world around us. It is hosted, written, and produced by Grady Hillhouse. We have new videos posted regularly, so please subscribe for updates. If you enjoyed the video, hit that ‘like’ button, give us a comment, or watch another of our videos!

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This is not engineering advice. Everything here is for informational and entertainment purposes only. Contact an engineer licensed to practice in your area if you need professional advice or services. All non-licensed clips used for fair use commentary, criticism, and educational purposes.

SPECIAL THANKS
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This video is sponsored by Ground News.
Stock video and imagery provided by Getty Images, Shutterstock, Pond5, and Videoblocks.
Tonic and Energy by Elexive is licensed under a Creative Commons Attribution License
Video by Grady Hillhouse
Edited by Wesley Crump
Produced by Ralph Crewe
Graphics by Nebula Studios

[andrewjmarx]

I interned for the Santa Monica Mountain carnivore monitoring project over a decade ago. One of the bobcats we were monitoring went missing. I found its body Christmas Eve on the edge of the 101 almost exactly where the Wallis Annenberg Wildlife Crossing is now. It took two decades of wildlife monitoring, full of people with sad experiences like mine, to finally see this happen.

[ryans]

Engineering to help people and nature to better coexist is some of my favorite engineering.

[MrHugemoth]

After the highway department installed a couple wildlife crossings on hwy 97 in Oregon deer collisions went way down. Works great!

[Tiffanyeo]

On an animal overpass in Norway, I once observed a large moose come up to the middle of the overpass and then stop to watch the cars passing beneath him for a few moments before continuing on his route. The silhouette of the large moose on top of the overpass, monitoring the automobiles on the highway, was a breathtaking sight.

[MiHIT]

Sometimes, animals can adapt too much. They built new road next to small lake. This caused an issue for frogs that were trying to get to it. So they made underground passage for animals. Two years later and storks found out that why bother searching for frogs when they have to use this passage. So in the season, you can always see one or two storks standing next to entrance enjoying all you can eat frog buffet

[hub.ski_]

I must correct something. With the dimmensions you provided it definetly is not the biggest in the world. The wildlife crossing near me in Poland (Coordinates via Google Maps: 51.56354422392632, 16.862301457556867) is 310, 55 m (1018, 85ft) wide and 100, 96 m (331, 23 ft) long. And I'm pretty sure it is not the biggest either.

[noahh]

While in community college studying up to start pursuing my engineering degree, I was mesmerized by the Yellowstone to Yukon (Y2Y) project, and it became a primary topic for me to reference when telling people what I'd want to do with my degree.

Taking my FE exam in 2 days, and then hopefully I'm going to start working on projects exactly like this. Thanks a ton, Grady, for featuring animal bridges right when I needed a reminder on my motivation!

[KevinT]

I think one of the biggest difference is that animals can't read signs, while humans don't read signs. Either way, you have to engineer a bridge to be so obvious and intuitive that it won't be disused.

[kickpushlongboards]

Bridge engineer in Arizona, just finished designing my first wildlife bridge!

[jesperwall]

I work for the Swedish police to track traffic wounded animals, so this video was right up my alley 👍 Here in Sweden, if you hit any animal like a row deer or bigger, you have to call the police. Even if you don’t think the animal is wounded. The police then sends out one of us trackers, and we do a search for the animal with our dogs to either make sure that the animal is not wounded, or to put it to sleep.

[JoelReid]

In Perth, Australia, there is a nature reserve along the river called the "Canning Reserve". the interesting thing is south of this reserve, the suburbs have been designed with "nature corridors". These are essentially drainage ditches, but are planned to link up the various parks of the area. The idea with these corridors is that animals can move from the reserve to the parks via these corridors. Considering that the reserve is a wetland, and the parks all have small lakes in them (often with reeded areas along the banks), this is designed to supplement the local ecosystem and allow the natural environment to mesh with the suburban environment.
Long neck turtles, birds, insects, and amphibians all use this network of corridors to keep each parkland freshly supplied by animals.

[Thomas-vncr]

No mini road setup in your garage with adorable miniature animals?

[SoulerBk]

I live in small town in Poland on the edge of a major forest and on the intersection of two major express roads (basically a highway considering how they are almost the same as highways in Poland, but free from most of the pricy regulations that make building highways in EU a huge investment) and wildlife crossings are something that just seem to pop up more and more (by now I think there are like five of them around) and, seriously, I'm thankful they exist. Once I was going back from work outside of town in the winter and I fell off the bike because of group of boar crossing close to the town limits, luckily I just bruised myself (it was slippery and after my bike stopped I just fell to the side), outside of the express way collisions with wildlife are happening all the time. Nice to see a video on the topic, it also makes me feel proud that Poland doesn't have only to put money into lifting country out of the gutter and has enough spare funds to make travel safer for both humans and the rest of animal kingdom.

[GerardoRivera-lk]

I think it's great how your video covers several conservation biology and genetic conservation points. It really shows how much you researched to produce a quality video. Lots of engineers would not bring in biology points and just focus on the engineering part. Keep up the fantastic work.

[mpetrino]

Grady hi from Alberta, Canada. Great topic one which most highway users never give a second thought to. Here inside Banff National Park where the six lane Trans Canada Highway cuts straight through the park wildlife corridors were made a priority 15 years ago. Today there exists a total of 44 wildlife corridors, six overpasses and 38 underpasses within park boundaries. Research since construction prove they work. So much so the Province of Alberta Transportation Dept is currently constructing 3 outside the park overpasses and planning 2 more. Currently Parks Canada and Montana State University are working together monitoring existing wildlife corridor use and researching new designs.
Wildlife crossings are responsible for raising the Black Bear, Mountain Lion, Coyote, Deer Family and Moose populations within Banff National Park back to 1970's levels.
Again great topic as a B.Arch won't make any P.Eng jokes 😁.
Thanks

[ScoutSilico]

As a Washington State resident I absolutely love the wildlife crossing they put in over I-90 up in the mountains. I love watching the nature cams and seeing the deer and other animals cross over the area that we previously made inaccessible.

[fragglet]

Watching the news it always seems like only terrible things are happening in the world, but the fact we're willing to invest time and real money in projects like this gives me some hope for humanity.

[robertmacleod]

I attended a webinar about one of the wildlife crossing projects in Banff (Alberta) earlier this year. It's super interesting infrastructure, glad to see you covering it and sharing the knowledge with a larger audience!

[HenriettaBrix]

We have an overhead wildlife crossing here in Singapore.

I have the ecological appreciation for it and now after watching your video, an engineering appreciation for it.

[katieluv]

Never would have thought someone would teach me more about roads and animals than I already know. Super impressed by the details in this episode and your passion for it really shows.