World's largest wildlife crossing reaches critical milestone. Now what?
69 comments
·April 1, 2025WillAdams
AyyEye
While I agree with the sentiment --that couple's methods leave something to be desired.
The article makes it sound like they took a motor boat into a wilderness preserve? Motor vehicles are explicitly not allowed in those areas.
Also excluding dirt roads is a pretty bad criteria. A lot of GIS marked 'dirt roads' are natural animal trails or washes that have been around for hundreds/thousands of years.
mikestew
The National Parks Service allows it:
While motorboats are permitted to operate in the marine environment, their presence can influence the wilderness setting.
kjkjadksj
US doesn’t even have this for humans to cross at regular intervals on all freeways.
OtherShrezzing
This is a great initiative which I fully support. But why does it take 4-6 years (including several months of complete road closure) to build what is, in the grand scheme of things, a quite small bridge?
icegreentea2
So the article says that Agoura Road (which is not the highway) will be closed, but the project FAQ still says that it won't be? And the government pre-notices don't seem to mention anticipating closing the road either...
https://101wildlifecrossing.org/crossing-faq/
https://www.agourahillscity.org/Home/Components/News/News/39...
smithkl42
Completely agreed. All the nonsense about getting just exactly the right soil composition, letting the soil "age", and what-not, seems bizarre and silly. If an animal needs to use the bridge, it'll learn to use the bridge. Spending so much extra money and time to get the vegetation just right is a waste of taxpayer dollars.
gamblor956
Believe it or not, the people that design and build these bridges have a lot more experience than you do. So if they're doing something that doesn't make sense to you, you should ask yourself what you're missing, and not question their basic competence.
The point isn't just to make a bridge, or they would use a simple concrete bridge.
The point is to make a bridge that is preferable to crossing the highway. And to do that they need to landscape it as if it were part of the landscape. That takes more time because the bridge needs to be stronger to handle the weight of the soil and plants, which means the design, permitting, and construction phases are longer.
They're closing the surrounding road for the soil movement part of the project because that part of the project entails risks of landslides, and it's safer to just close the road. However, the road won't be closed the entire time; it will only be closed for a few hours at a time. The months-long period is just the part of the project when the road will be subject to potential closure.
BurningFrog
This is lightning speed for California construction...
kjkjadksj
They can go hyperspeed if they want. See freeway building after northridge earthquake or when they replaced an entire bridge over the 405 in one night.
kjkjadksj
Because they aren’t building a cheap old bridge animals will probably learn to use. They are effectively regrading the mountainside and landscaping over this bridge to try and blend it in with the landscape. Imo its a waste of money. Crabs learn to use the dead simple ugly bridges. Crabs. A coyote or a mountain lion or deer (what you’d see using this thing in CA) all already use human style bridges to cross highways.
kibwen
Roads are such an apocalyptic blight on the landscape that I'm all for burying as many of them as possible. 200 feet down, 200 billion feet to go.
panick21_
Or you know, crazy idea, just have less roads, use something more efficient less impactful to nature. Can't imagine what that could be.
bluGill
It doesn't matter, there are downsides.
In an ideal train world you still end up with railroad tracks everywhere that interstates exist with the same wildlife downsides. Running trains at ground level is an order of magnitude cheaper to build than building it elevated so wildlife can go under. Running underground is another order of magnitude more expensive. The expense directly relates to how much we can build at any one time - we can build a lot more if we choose run on the ground.
In the ideal train world you still end up with roads everywhere because "last mile" freight needs to get places and trains don't work well for it (think your kitchen trash). Passenger trains always rely on the fact that people can walk a short distance to the train, but freight cannot walk. Passenger trains also cannot be blocked by freight loading/unloading which means you need a separate road system. Passenger trains need to run frequent, you might not go anywhere in the next half hour, but someone on your block will and if the trains are not frequent (every 5 minutes or less) cars are a great quality of life improvement: unlike cars passenger trains cannot mix with freight and be good in areas where things are not busy (A bus can mix with freight well in less busy areas, but they still need to be frequent and that is rarely the case again pushing people to cars and thus against what "you can't imagine"). This in turn means we have more places wildlife is blocked.
Airplanes are the only exception, but they don't cover all the needs and so even if we forced everyone to fly for longer trips (at significant climate costs) we still need all the roads in the middle of nowhere for the people (farmers) who live in those ares.
WorldPeas
maybe this is why Brin and Allen were so obsessed with airships, not to speculate too much but they sound like they could be an ideal short-run, low-impact, high capacity transit system if done right
jajko
Hate to burst anyone's bubble but trains in its current form aren't solution to mass transit. They help, sure, under certain circumstances, but are very costly to run and in peak you need huge amount of them. 1 disruption and everything stops, you can't just take an exit and go through villages.
Case point Switzerland, the train country of this world. Efficiency, cleanness, reach, small country. Yet its prohibitively expensive here and highways are chock full of commuters just like anywhere else. For weekend trip ie to mountains they (+ post buses where trains don't go) are very restrictive which is understandable, but car becomes a must anyway.
lacrosse_tannin
The roads and the borders
LinuxBender
Put all human infrastructure under ground so that one is left with a beautiful mostly untouched planet. Addresses some aspects of global climate change no further need for HVAC. Reduces power load on the grid. Animals can have the surface of their planet back.
loloquwowndueo
Zero animals live underground, this will totally work.
Evidlo
It would work because underground animals live in a 3D world, unlike surface animals.
loloquwowndueo
Sorry what?? :)
LinuxBender
Once you go deep enough this is true excluding bacteria because to hell with bacteria.
filoeleven
Bacteria are not animals.
eitally
Maybe the PP just finished watching Silo....
paulcole
But he’s a computer programmer so obviously his expertise extends into all other areas.
williamdclt
I don’t think this was a serious comment
theamk
I am sure that some people would still want to live on the surface of that beautiful, untouched planet. And I am sure this could be arranged, for the right price of course. And as the extra bonus, all those rich surface-dwellers would not need to see the common folks and other riff-raff, who would be be living under the ground. Hey, even under ground could use the same system: top levels for more well-off folks, and lower levels for poorer folks.
I think I've read a book about this. Or ten.
LinuxBender
Dystopian are my favorites. I have this fantasy that there are still some people that would rise up to the challenge and level the playing field.
bombcar
Underground subways heat up the rock so much they have to add cooling eventually.
LinuxBender
Much of the heat from a subway comes from the HVAC in the train. Add more venting to the trains that works with the trains movement and use forced air into the tunnels. Costs more but it can be done. Some of the heat comes from acceleration and braking. Make that more efficient with newer electric motors, better designed tracks, better regenerative braking. If that doesn't work require everyone to disrobe before leaving their underground home.
Another option would be to deprecate trains. Instead people travel through pressurized maglev modules in tubes at 800 mph / 1200 kph. Transcontinental tubes accelerate the modules to 8000 mph / 12,000 kph. Interplanetary offramps eject the module from earth at mach 50+ where it is caught by a sub-orbital robot ship that matches speed and takes the module to the interplanetary colony ship.
zipy124
https://en.m.wikipedia.org/wiki/London_Underground_cooling
It's significant.
theoreticalmal
Ahhh Delta-V by Daniel Suarez! Great book. The human-controlled robots were really interesting imo
pirocks
London underground deep level trains have no HVAC and most definitely have overheating tunnel problems.
ratatoskrt
You've clearly never have been on the London Underground - none of the deep level lines currenlty have air conditioning and yet they are getting hotter every year.
verisimi
When I see this sort of comment, I feel like saying: 'well, go on then - you lead the way. If it's really a viable and pleasant way to live, why don't you show us?'
LinuxBender
I have been planning it out but only for my property. I can not afford to build the national, international or interplanetary bits. Getting a good team together at my location is my only obstacle. It's very hard to find a solid general contractor and team here that will build as designed in phases. They want to do it all in one shot but that introduces a lot of legal risk if they are doing it wrong.
I love being underground. It's cool and quiet. Those facilities also last a very long time. I found many "Kilroy was here" scribbles in tunnels in the military and some of them were dated back to WWII.
jvdvegt
Is it the biggest wildlife crossing? This one [1] is 50x150 meters. Granted, it's in flat land so it's not covered with such a thick layer of soil.
[1] https://www.atlasobscura.com/places/natuurbrug-zanderij-crai...
gamblor956
The difference is in what's being measured.
According to the Dutch Wikipedia article, the Zanderij Crailoo bridge is a multi-purpose bridge that includes a hiking path, bike path, and horse trail, in addition to a wildlife crossing.
The Agoura Hills is just a wildlife crossing. So it would be most accurate to say that the Agoura Hills crossing is the single biggest dedicated wildlife crossing.
hooo
Yea, I find it hard to believe that is the largest.
teekert
One wonders about why they didn’t choose a tunnel, leaving that ultra special soul fully intact…
jkuria
Why is there no wildlife? I expected this to be about the Maasai Mara/Serengeti wildebeest crossing :)
zoklet-enjoyer
Why is this taking so long to complete?
throwup238
Because they’re trying to do it the right way. The rain we’ve experienced the last few years has been the biggest problem. The soil they’re piling on top of the crossing erodes away almost immediately without plant roots to stabilize it and those plants take a while to establish.
zoklet-enjoyer
Oh, yeah I see it mentions that in the article. I didn't read the article before commenting because I had read another article about this project recently and didn't think there would be anymore information. I was wrong.
recursive
Does this type of wildlife crossing actually work?
dgacmu
Yes. 80-97% reduction in vehicle-animal collisions, per: https://www.sciencedirect.com/science/article/abs/pii/S00063...
> If wildlife fencing and crossing structures are designed based on the requirements of the target species, and if they are implemented and maintained correctly, the measures can reduce large mammal–vehicle collisions by 80–97% (Clevenger et al., 2001, Gagnon et al., 2015, Sawyer et al., 2012).
kjkjadksj
Any type works. This one is stupid elaborate. Animals are smart. They don’t need a graded landscape to learn crossings. See what they use for crab migrations. Looks nothing like what is native in a crab environment and yet this is fine for the simple crab. Meanwhile coyote already is used to walking on our sidewalks in california.
thimkerbell
Clickbait title.
aaron695
[dead]
pizlonator
Yes! Let's build this stuff instead of homes.
dgacmu
Don't give in to zero sum thinking.
https://www.opb.org/article/2022/08/31/animal-crossings-over...
> Sugiarto found a favorable cost-benefit analysis. The study estimated each crossing structure could save society between $235,000 and $443,000 annually through collision reductions. The savings varied based on structure size, design and location.
crazygringo
The two have nothing to do with each other.
We've got plenty of money to do both.
The issues with homebuilding are entirely to do with regulation, zoning, etc. Developers will build homes if they're allowed to. Banks will give them the loans (homes don't require government money). The problem is them not being allowed to. Because you're not allowed to build multi-family homes in a neighborhood, you're not allowed to build tall apartment buildings, approvals take forever, etc.
The U.S. needs similar crossings for all the regions separated by the Interstate system, and somewhere near the center of each region so created, a large wilderness preserve which has roads removed:
https://www.bbc.com/news/world-us-canada-42104894