[HN Gopher] Largest Wildlife Bridge Spanning 10 Lanes of CA 101 ...
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Largest Wildlife Bridge Spanning 10 Lanes of CA 101 Is Nearly
Complete
Author : PaulHoule
Score : 128 points
Date : 2025-06-18 23:43 UTC (3 days ago)
(HTM) web link (www.thedrive.com)
(TXT) w3m dump (www.thedrive.com)
| erulabs wrote:
| The book "the lion in the living room" documents P-22 and LAs
| love for the cat very well, it's a great read and I recommend it.
|
| As much as I'm happy about this I find myself skeptical that
| wildlife will learn to use it. Do animals walk along the side of
| the highway looking for openings? Have there been any studies on
| the efficacy of these wildlife bridges?
| PaulHoule wrote:
| https://environmentamerica.org/articles/do-wildlife-crossing...
|
| https://pmc.ncbi.nlm.nih.gov/articles/PMC9753749/
|
| In my neighborhood (NY not VA) we had some people make a
| crossing for these guys this spring
|
| https://www.virginiaherpetologicalsociety.com/amphibians/sal...
| idiotsecant wrote:
| There is one east of Seattle that gets used by wildlife quite a
| lot. When you're up there the interstate is very quiet due to
| all the earth between you and it, and they keep both sides of
| the crossing well wooded and obscured from view from the
| interstate. The animals figure out pretty quick where to cross.
| poopsmithe wrote:
| That one's cool because animals can cross over or under
| https://www.youtube.com/watch?v=Cf5nMLrlgW4
| bahmboo wrote:
| There are also fences along the freeway for what seems like
| miles. That's to funnel the animals to the crossing. There
| are also 10 or so under crossings drivers can't see.
| 0points wrote:
| Here in Sweden, we have great success with wildlife bridges and
| more is being built, along with wildlife passageways (for when
| large animal end up on the road, there's a way out for them
| through the wildlife fences).
|
| Studies: https://triekol.se/triekol-3-eng/over-and-underpasses-
| for-la...
| ahoef wrote:
| These are all over The Netherlands and widely used by animals.
| xnx wrote:
| > Do animals walk along the side of the highway looking for
| openings?
|
| There's precedence in the natural world. A single log can get a
| lot of use by all types of critters:
| https://www.youtube.com/watch?v=qsDU_tTgsFw
| kjkjadksj wrote:
| They will use it but they also use bog standard cheap bridges
| too. Imo making it look like natural landscape for $$$$ is kind
| of stupid.
| gregfjohnson wrote:
| I wonder if there are any plans to place meat along the bridge
| to attract mountain lions. Will ecologists try to "train" the
| wildlife to use the bridge, or just let nature take its course?
| sanktanglia wrote:
| There is a wildlife bridge like this in orange county where I
| used to live and it was very often used, it is directly
| responsible for increases in their numbers
| rurp wrote:
| Yep these bridges have been researched and found to be quite
| effective. It sounds like this bridge was unusually expensive
| but on average they even work out to be neutral or +EV on cost
| due to all of the prevented accidents.
| jonstewart wrote:
| Introducing wolves back to a relatively small part of Wisconsin
| has had a positive economic impact from reduced car crashes with
| deer. This crossing will no doubt help the cougars, and that'll
| help the humans who have to drive on this terrifying part of the
| 101.
|
| https://wolf.org/media-releases/new-study-shows-wolves-save-...
| rurp wrote:
| One of my favorite wildlife stats is that you're _hundreds_ of
| times more likely to be killed by a deer than a mountain lion.
| Protecting apex predators like wolves and lions significantly
| reduces deer caused deaths and injuries. It 's nice to see
| public opinion steadily changing in this area for the better,
| past predator management has been extremely stupid and harmful.
| downvotetruth wrote:
| > having required 26 million pounds of concrete
|
| the height restriction alone should have been reason enough to go
| with a tunnel, but how could CA miss an opportunity for
| construction waste /s
| jeremyjacob wrote:
| I believe they chose a bridge to create a more uniform natural
| path across the freeway so that the animals will be more likely
| to utilize it. There's already an overpass a half mile to the
| south that would allow a crossing over frontage roads but
| because it's not obvious and wild enough, animals still cross
| on the freeway.
| downvotetruth wrote:
| The first sentence is almost completely subjective, and the
| leading fact in second sentence gives the best evidence
| against an overpass in this thread. The only thing that is
| going to make this more obvious to the mountain lions would
| be a few more dead deer carcasses as a result of the _car
| lights! lets jump off the side into oncoming hidden traffic
| behavior_.
| jmye wrote:
| You'd think the right thing to do would be to pick the option
| wildlife is most likely to use, and that there was research and
| decision-making that went into that above and beyond "tons of
| concrete".
|
| Do you think that _didn't_ happen, that you're significantly
| smarter about wildlife bridges than the folks who planned this
| one (who were, apparently, too dumb to ask a question you
| thought of sixty seconds after reading about the amount of
| concrete used), or just deeply into throwing shade, deserved or
| not, at CA at every half-imagined opportunity?
| downvotetruth wrote:
| No, I do think that happened and that the underpass was the
| more reasonable solution; why Caltrans required due to the
| bridge's size and cost to have its completion be reliant on
| donations from the public.
| cruffle_duffle wrote:
| Perhaps rephrase as "designed as an underpass". These things
| already are funnels for prey. I doubt a lot of wildlife is
| going to feel comfortable going through a tunnel. Humans don't
| like going through tunnels to cross highways...
|
| Because I agree about the cost of these things. They should be
| designed to be inexpensive so we can put them everywhere (eg:
| i90 through cascades... there is only 1 of these and it's on
| the east side of the pass).
|
| It annoys me greatly how seemingly over engineered and expense
| these are. We put a huge fence that divides the entire mountain
| range. These bridges should be all over.
|
| That being said I'm pretty sure a lot of research goes into
| designing a wildlife bridge that animals want to cross. I think
| there was a practical engineering YouTube video that covered
| it. Turns out each species has their own preferences and
| peculiarities when it comes to this sort of thing. So to
| counter my own argument... it does no good to build a ton of
| these if no animals will actually feel comfortable using them.
|
| Maybe they should fund some kind of wildlife outreach program
| and give brochures and flyers to the local wildlife explaining
| how to use their new overpass...
| toast0 wrote:
| > Maybe they should fund some kind of wildlife outreach
| program and give brochures and flyers to the local wildlife
| explaining how to use their new overpass...
|
| For the Snoqualmie bridge, (some of) the local wildlife
| trespassed to use it before it opened, so I'm not sure if
| they need to do much outreach.
|
| I think the better projects include post construction
| observation and reasonable minor modifications to help
| encourage use; typically adjustments to fencing or maybe some
| earth works.
| toast0 wrote:
| Tunnels are probably more expensive than overpasses. At best,
| they might be comparable cost.
|
| Especially if you want to do the work with minimal disruption
| to the highway.
| downvotetruth wrote:
| Cutting and covering a few lanes at a time would not have
| cost $92 million. Even better, a horizontal drill would have
| less chance of lane closures than the bridge option.
| firefoxd wrote:
| You might enjoy learning more about these projects from
| Practical engineering:
| https://youtu.be/5mYpQWPtfpo?si=riybniIFEjbwDMWQ
| downvotetruth wrote:
| I already saw that video and my comment reflects what he
| states that underpasses usually cheaper than overpasses like
| this (9:10); given that fact more (culverts - 9:30) could be
| built for the more numerous non-apex species that do not lend
| well to being diverted miles to such a monstrosity. Of the
| listed species expected to benefit from this crossing
| including bobcats, coyotes, gray foxes, birds of prey,
| skunks, rodents, American badgers, American black bears,
| fence lizards and mule deer only the mule deer have may be
| having herding behavior causing carelessness to not use such
| an underpass.
| ksec wrote:
| I had to google and double check there isn't another place in
| Europe called Santa Monica Mountains. Because building bridge for
| Wildlife seems very European rather than American, or at least
| modern American. I remember a lot of them in Holland and other
| places.
|
| Let's hope more of these get built in US. ( While not being crazy
| expensive )
| vondur wrote:
| Ha, this is California and it cost 92 million US dollars
| bruce511 wrote:
| More interestingly is the timeline. Broke ground in 2022,
| finished in 2025, and likely operational before the end of
| the year.
|
| Now sure, it likely took some years in the planning as well,
| but it shows that infrastructure _can_ be built in reasonable
| time lines when politics and nimbyism don 't get in the way.
|
| And this isn't a simple bit of construction- it spans a
| serious bit of active highway.
| bhaney wrote:
| > shows that infrastructure _can_ be built in reasonable
| time lines
|
| This bridge for deer took 3 times longer to build than the
| Empire State Building.
| maxbond wrote:
| A bridge for deer isn't any easier to build than a bridge
| for pedestrians, even if you don't care about deer being
| on a bridge that collapses there's a highway underneath.
| Cars would be crushed and traffic disrupted. So we're
| just talking about a bridge. It's built to the same
| standard as any other bridge. (Also it's more like a
| bridge for mountain lions but whatever.)
|
| If the Empire State Building had been built across a
| highway, and had to schedule construction around avoiding
| disruptions to traffic, than it would've taken three
| years too.
| WalterBright wrote:
| Bridges for pedestrians are far lighter construction than
| bridges for cars and trucks.
| xeonmc wrote:
| Pedestrians are also far lighter than cars and trucks,
| and slightly lighter than deers.
| bayarearefugee wrote:
| 5 people died constructing the Empire State Building.
|
| 0 people died constructing this bridge.
|
| I guess if you think working class people's lives aren't
| important then the human cost doesn't matter to you, but
| for non-sociopaths it does matter.
| SoftTalker wrote:
| But in general, workers on road projects are killed every
| year. Yet we still build roads.
| toomuchtodo wrote:
| We went faster when human life had less value. It has
| more value now, both in labor time (and therefore cost)
| and harm potential/reduction, so it takes more time and
| money than it used to. Similar story about disposable
| workers when the Hoover Dam was built.
|
| We should expect this math to continue as prime working
| age cohort shrinks over the next century due to
| structural demographics.
| edflsafoiewq wrote:
| Certainly this is a factor; is there a reason to think it
| is a significant one?
| sanktanglia wrote:
| For deer? It's much more for the endangered wild life
| like mountain lions. I loved in so cal and we had
| multiple passes like this and it was incredibly helpful
| in maintaining the mountain lion population
| vl wrote:
| However you slice it, the time it took for this project to
| complete is absurd. Project started in 2002, it took 20
| years to plan this, then it took 3 years to build this low-
| tech bridge.
|
| Even without looking at China and Middle East - in Texas
| they build entire highway intersection in a year.
| ryandrake wrote:
| Morbidly curious, I'd love to see a full cost and time
| breakdown of these projects to understand exactly where
| the $100M and 3 years goes. How much of that is actual
| people wearing boots and hardhats, and how much of it is
| paperwork, and waiting for this inspector to inspect that
| thing and then unblock this other bureaucrat to stamp
| onto that other paper. I'd bet the actual amount of time
| and money spent actually building was a single digit
| percentage vs. the amount of time and money spent on
| process and paperwork and waiting for clerks to go
| through their 1,000 item backlog of forms to fill out and
| stamp.
| mosdl wrote:
| Bridge in earthquake zone vs an intersection is a great
| comparison!
| derektank wrote:
| Many places in the US have already built dedicated wildlife
| crossings. There's the Keechelus Wildlife Overcrossing over
| I-90 in Washington state and Wyoming has invested in several
| smaller scale over and underpasses along Highway 191
| Gibbon1 wrote:
| There is also the Nutty Narrows Bridge in Longview,
| Washington.
|
| https://en.wikipedia.org/wiki/Squirrel_bridge
| Yeul wrote:
| Wait until you see the bridge with a canal on it...
| api wrote:
| This is not a bad thing, but my first thought was: anything but
| housing.
| michaelrmmiller wrote:
| I live nearby and drive past it nearly every day. It's been
| fascinating watching its construction. They've done a very good
| job not impacting traffic and only closed down the highway late
| at night for a week or two.
| conradev wrote:
| Yeah! The first time seeing it was funny, a bridge with no
| roads. Excited for it to open. It's a bummer that it cost $100m
| WalterBright wrote:
| At those costs, very very few will be built.
|
| More modest projects should be considered. Like simple
| bridges, or large culverts running underneath the highway.
| bartvk wrote:
| I wonder why they didn't opt for your suggestion for
| multiple modest projects.
|
| The article doesn't mention it, it only says:
|
| > National Park Service began a decades-long study of the
| region's mountain lion population that the 101 freeway was
| deemed "the most significant barrier to the ecological
| health of the region."
| eszed wrote:
| A big reason (this is from the project site):
|
| > NEPA Completed 04/12/2018: Finding of No Significant
| Impact (FONSI), Liberty Canyon Wildlife Habitat
| Connectivity Project
|
| > In compliance with CEQA, Caltrans held a 47-day public
| scoping period to allow the public and regulatory
| agencies an opportunity to comment on the scope of the
| IS/EA and to identify issues that should be addressed in
| the environmental document. A scoping report documents
| the issues and concerns expressed during the public
| scoping meetings held on January 14, 2016 and the written
| comments received from the public, community
| organizations, and governmental agencies during the
| public scoping period from December 14, 2015 through
| January 29, 2016. The release of the Final Environmental
| Document with responses to comments included was
| completed in the summer of 2016. NEPA/CEQA was completed
| in April 2018. A total of 8,859 comments were received in
| response to the draft Environmental Document, with only
| 15 opposed.
|
| When any infrastructure project requires nearly a decade
| of preliminary work before shovels hit ground, said work
| becomes impossible to accomplish for smaller-scale
| builds. Even if ten smaller bridges would be a better
| solution, 10x-ing the review process would likely be
| impossible at current staffing / budget levels.
|
| It's a big problem.
| Espressosaurus wrote:
| If it's too small/unsafe you'll end up with wildlife not
| using it or being funneled in for other for predators.
| The larger and more skittish the animals you want to use
| it, the larger you're going to want to make it. Since
| they're calling out mountain lions, which are quite
| skittish, they're going to need a large (and probably
| partially covered) pathway for them to want to use it--as
| opposed to treating the freeway like the barrier it is to
| wildlife.
|
| I'm sure there's more to it than that, but making it
| desirable, accessible, and for it to feel safe for the
| target animal population is important for it to
| accomplish what it's intended to do.
|
| There are smaller culverts all over the place for smaller
| wildlife. I've even seen some called out in small walking
| paths--there for the frogs and other amphibians.
| ourmandave wrote:
| I would pay stupid money to have _America_ change the lyrics to
| _Ventura Highway_ to include the overpass and then perform it at
| the ribbon cutting.
|
| Like Elton did for Diana with _Candle in the Wind._
| thaumasiotes wrote:
| Don't tell us, tell them.
| labster wrote:
| The hardest part might be getting them to wake up early enough
| for the ribbon cutting. I saw America perform at the Ventura
| County Fair around noon, and they complained it was the
| earliest gig they had all year. But it was Ventura Highway in
| the sunshine, which was its own kind of awesome.
| sameline wrote:
| For those interested in learning more about road ecology,
| Crossings is an interesting read.
|
| https://www.goodreads.com/book/show/123627807-crossings
| komali2 wrote:
| Gigantic roads like that make me crazy! I can't understand how
| people subject themselves to living near these giant impassible
| rivers of concrete! Even a city road that's not a freeway - on a
| visit to sf I needed to walk across Harrison and then 6th street.
| 12 lanes to walk across, two lights to wait for! I felt like
| tearing my hair out.
|
| At least they finally built a way for the animals to cross again.
| I can't imagine how long it would take to walk across that eco
| bridge thing.
| jedberg wrote:
| I grew up in Agoura Hills, it's funny to see this on HN of all
| places. And in another amusing twist, I just drove under this two
| days ago because I am visiting my parents this weekend.
|
| It's something the locals have known was needed for a long time,
| I'm glad they were finally able to get it built.
| WD-42 wrote:
| SoCal is a lost cause. Paradise lost. But i applaud the effort
| anyway.
| wwweston wrote:
| There's still plenty of great landscape to preserve and wander
| around the metro area ( at least as long as it doesn't get sold
| off by venal hacks like Mike Lee).
| superdude12 wrote:
| Considering it doesn't have to carry much weight, why couldn't
| they make it out of wood to cut costs?
| mrj wrote:
| Dirt is pretty heavy. As the article said, the next step is to
| add native plants to the top.
| mulmen wrote:
| I would be shocked if material costs are within an order of
| magnitude of the labor and design costs.
| quickthrowman wrote:
| There are (at least) thousands of tons of soil on top of the
| reinforced concrete.
| randmeerkat wrote:
| Amazing, California can build a wildlife bridge, but god forbid
| they build higher density housing.
| daedrdev wrote:
| Is this not also a wildfire bridge? I know freeways are usually
| important wildfire breaks but I guess its easier to know thus is
| here ahead of a fire
| bartvk wrote:
| Weird how you're downvoted. IMHO, it should not stop its
| construction, but it's an interesting question. Undoubtedly,
| after dumping soil on the bridge, shrubbery and even trees will
| grow, so yes, it could act as a wildfire bridge.
|
| Note that the article also says it offers an escape route from
| wildfires, so it goes both ways.
| libraryatnight wrote:
| If had to guess about the downvotes: the note about the
| article you point out (that's the big reason), plus (and this
| was just the first thing of a handful of relevant
| information) the easy answers with a quick search
| https://valleynewsgroup.com/wildlife-bridge-wont-become-a-
| wi...
|
| Which took less typing to find than making the comment.
| suzzer99 wrote:
| It's pretty easy to protect one bridge if the fire gets close
| from either side.
| netsharc wrote:
| Huh, why does the embedded video look like someone played it over
| a Zoom screen-sharing session, and another participant of that
| Zoom meeting did a screen record?
| mrlonglong wrote:
| Over in the UK we're just finished building one on the M25, the
| world's biggest car park during rush hour.
|
| https://www.theconstructionindex.co.uk/news/view/wisley-sche...
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