Few individual animals have ever been more important to their species than 2323M — a red wolf, dubbed Airplane Ears by advocates for his prominent extremities, who spent his brief but fruitful life on North Carolina’s Alligator River National Wildlife Refuge.

Red wolves, smaller, rust-tinged cousins to gray wolves, are among the world’s rarest mammals, pushed to the brink of extinction by threats such as habitat loss, indiscriminate killing, and road collisions. By 2019 fewer than 15 were known to survive in the wild. Against that grim backdrop, 2323M offered hope.

Born at a federal site in Florida, he was released in 2021 onto the Alligator River refuge, a swath of coastal plain on North Carolina’s eastern shore. Over the next two years, he and a female known as 2225F raised 11 pups.

Alas, in September 2023, Airplane Ears was killed by a car on US 64, the highway that runs through the refuge. One of the world’s rarest species had lost its most prolific member.

Airplane Ears was an extraordinary animal who suffered a common fate. Around one-fifth of red wolves meet their end on a bumper, many on US 64, a primary route that vacationers take to the Outer Banks, the picturesque chain of barrier islands that line North Carolina’s seaboard. Black bears and white-tailed deer fall victim to collisions that kill animals and result in “significant harm to humans and vehicles,” according to the North Carolina Department of Transportation. Even the occasional alligator blunders onto the highway.  

While US 64’s roadkill rates are exceptional, it’s far from the only perilous highway in the United States, where animal crashes annually cost society more than $10 billion in hospital bills, vehicle repairs, and other expenses.   For species from Florida panthers to California tiger salamanders to North Carolina’s red wolves, collisions pose an extinction-level threat. 

After 2323M perished, a coalition of conservation groups began pushing the North Carolina Department of Transportation to retrofit the highway with fences and underpasses — essentially spacious tunnels that would allow red wolves and other animals to slink safely beneath US 64. “We knew that something had to be done, quick,” says Ron Sutherland, chief scientist at the Wildlands Network, a conservation group that focuses on habitat connectivity throughout North America. Otherwise, wild red wolves could be lost. 

Drumming up millions of dollars for wildlife crossings has always been a tall order. In December, however, North Carolina received $25 million from the US Department of Transportation to build underpasses on Highway 64. Combined with $4 million that Wildlands Network and the Center for Biological Diversity raised in donations, as well as state funds, it was enough to make a stretch of Highway 64 safe for wolves. “It felt really good to know that something had gone right for the red wolf, for once,” Sutherland says. 

That the transportation department invested in animal underpasses may come as a surprise — its primary mission, after all, is to facilitate human movements, not the peregrinations of wolves and deer. The 2021 Bipartisan Infrastructure Law (BIL), however, contained an initiative called the Wildlife Crossings Pilot Program, which allotted $350 million in competitive grants for animal passage,  the largest pot of federal funding ever earmarked for the cause. In addition to North Carolina’s red-wolf crossings, the program has awarded grants for nearly three dozen projects — some of which will aid imperiled species such as ocelots and desert tortoises, many more that will seek to avert dangerous crashes with large mammals like deer, elk, and moose.

“This is not ornamental,” Pete Buttigieg, Joe Biden’s transportation secretary, told Vox of the wildlife crossings program in an interview earlier this year. “This is something that ties into the very core of our mission, which is to secure the safety of the American traveling public.” 

Unfortunately for the red wolf and many other species, President Donald Trump’s administration may not agree. 

The future of the wildlife crossings program, and many similar initiatives that the BIL supports, is uncertain. Shortly after taking office, Trump suspended the disbursement of BIL funds, leaving hundreds of Biden-era initiatives twisting in the political wind. Will animal passages, traditionally an overwhelmingly nonpartisan solution, endure? Or will the Trump administration stymie crossings, and a plethora of other BIL projects, before they ever truly get off the ground — perhaps dooming red wolves, and many other animals, in the process? 

A tenuous renaissance for wildlife-friendly infrastructure

The Pueblo of Santa Ana is an approximately 79,000-acre shard of New Mexican desert that’s criss-crossed by roads. Highway 550 plows below the southwestern edge of the Pueblo, known to its Native inhabitants as Tamaya; to the east and south, I-25 barrels along from Albuquerque to Santa Fe, impeding the movements of elk, pronghorn antelope, mountain lions, and other species. As in North Carolina, constructing wildlife crossings and fences along these highways, says Myron Armijo, the Pueblo’s governor, will save the lives of both drivers and wild creatures. “These animals are part of our culture and tradition, and we have very high respect for them,” he said. 

It’s thus only fitting that the Pueblo is where Buttigieg chose to launch the wildlife crossings program. On a windy day in April 2023, Buttigieg spoke with tribal leaders, made a brief speech backdropped by one of the Southwest’s busiest interstates, I-25, and toured a concrete underpass, its walls scrawled with graffiti, through which animals already cross the interstate.

“You couldn’t help but be struck by the deep connection that these tribal communities have with wildlife and the natural environment,” Buttigieg said. “And at the same time, this is not just a spiritual concern, because they’ve also tallied up the car crashes that are caused by these wildlife-vehicle collisions that we can prevent with better roadway design.”

Over two rounds of grants since, the wildlife crossings program has awarded an eclectic array of crossings. Western states, where animals often move along clearly defined migration routes, have historically built more passages than Eastern ones, and the wildlife crossings program has duly channeled money to states like Colorado, for a major overpass on I-25 south of Denver, and Utah, for underpasses on Highway 89. 

But the program has also funneled money eastward. Maryland, New York, and Georgia are among the states that received relatively modest planning grants in December, and Maine earned $9.3 million to build a passage for moose and deer. 

“If you look at a map that overlays the projects from the first two rounds of funding, you will see coast-to-coast diversity,” said Renee Callahan, executive director of ARC Solutions, a group that studies and supports animal passages.

In today’s politics, wildlife crossings may seem like a flight of fancy, but in reality, they’re critical safety infrastructure. Deer collisions alone kill an average of 440 drivers annually, making white-tailed deer deadlier than bears, alligators, and sharks combined. One study found that underpasses in Wyoming prevented so many perilous, expensive crashes that the state was on pace to recoup their costs in just five years.

If the program has a shortcoming, it’s that it doesn’t go far enough. In 2024 alone, applicants requested $585 million in federal funding, nearly five times more than the transportation department made available that round. That left lots of worthy crossings unbuilt, like passages on Highway 191 south of Bozeman, Montana, that would have spared elk, deer, and grizzly bears.

Callahan, like many conservationists, hopes that the pilot program will eventually be made permanent, ideally at a minimum of $1 billion over five years. “There are thousands of projects where today, based on a flat-out cost-benefit analysis, we’re going to save money in the long term by investing in this infrastructure,” Callahan said. 

In Callahan’s view, the pilot program has another flaw: The states and other entities that apply are required to bring up to 20 percent of their project’s costs to the table, a serious obstacle to Native tribes, which, in Callahan’s view, shouldn’t be subject to the matching-funds obligation. That didn’t dissuade the Santa Ana Pueblo, who drummed up their share through a separate state grant. In December, the Pueblo learned that it had received close to $6.4 million to design passages on the highways bordering their lands. “I was totally elated,” Armijo said. No longer would the Pueblo be an ecological island in an ocean of asphalt.  

What will Trump mean for infrastructure? 

As John Oliver once observed, rarely is infrastructure sexy — and neither is retrofitting it for nature. Consider the National Culvert Removal, Replacement, and Restoration Grant Program, which allocated $1 billion over five years to fix decrepit culverts, the unglamorous pipes that funnel water beneath roadways. Derelict culverts both threaten the integrity of roads and block fish migrations; on one stream in western Washington, for example, a series of too-narrow, impassable culverts prevent salmon from reaching their spawning grounds, violating the fishing rights of the Jamestown S’Klallam Tribe.  

When the first round of culvert funding was announced in August 2023, the Jamestown S’Klallam received $4.2 million to replace a pair of outdated culverts and thus restore nearly four miles of salmon habitat. 

“It doubles as two things — it opens up blocked fish passage, and we’re repairing road infrastructure,” said LaTrisha Suggs, the Jamestown S’Klallam’s restoration planner. 

Now, however, such initiatives are in jeopardy. In his first month in office, Trump has proposed slashing budgets, environmental protections, and the federal workforce alike. Among his first acts was to sign an executive order, titled “Unleashing American Energy,” that instructed agencies to “immediately pause the disbursement of funds” authorized by the Inflation Reduction Act and the Infrastructure Investment and Jobs Act, pending review within 90 days. 

According to a January 29 memo from new Transportation Secretary Sean Duffy, that executive order has led the agency to evaluate and potentially revoke many of its existing funding agreements, including any that mention climate change or environmental justice. The order could violate the 1974 Impoundment Control Act, which prevents presidents from withholding congressionally authorized funds. On February 13, Pennsylvania Gov. Josh Shapiro sued the Trump administration, arguing that its funding freeze broke the federal government’s contract “to provide billions of dollars in congressionally approved funding,” and in late February the administration restored more than $2 billion to the state.

The wildlife crossings program is among the many confronting uncertainty. 

According to Erin Sito, US public policy director for the Wildlands Network, a number of states have been told by the Federal Highway Administration (FAA) that their grants are “on hold,” without any clear next steps. (The agency did not respond to a request for comment.) “It’s definitely caught up with all the transportation projects that are not getting funded or administered at the moment,” Sito said. The Santa Ana Pueblo is among the affected recipients: Glenn Harper, the Pueblo’s wildlife biologist, said that the FAA informed the tribe that its grant was “on pause,” though Harper remains optimistic that the Santa Ana’s crossings will eventually move forward.

Delays notwithstanding,  conservationists still have ample reason to hope that the program will ultimately endure. As Deb Kmon Davidson, chief strategy officer for the nonprofit Center for Large Landscape Conservation, puts it, wildlife crossings tend to be “super bipartisan.“The preservation of migration routes enjoys broad support in red-swinging Nevada and in blue Oregon, and in conservative states like Wyoming, hunters are among the issue’s staunchest champions. Sen. John Barrasso (R-WY) included a forerunner to the wildlife crossings program in a 2019 highway bill, and US Rep. Ryan Zinke of Montana, who served as interior secretary during Trump’s first term, implemented a secretarial order directing Western states to protect big-game habitat and migration pathways. With Reps. Don Beyer (D-VA) and Alex Padilla (D-CA), Zinke is also cosponsor of the Wildlife Movement Through Partnerships Act, a bill that would help states, tribes, and federal agencies study and protect animal corridors, which was reintroduced to Congress in January. Animal passages may be that most endangered of Washington species: a relatively nonpartisan issue.

“Frankly, when we launched this program, I was ready for folks from the other side of the aisle to pounce and say, ‘Oh, you’re building highways for bunny rabbits,’ … when actually some of the strongest and most enthusiastic responses we got were from Republican legislators from states that have confronted wildlife-vehicle collisions on a daily basis,” Buttigieg told Vox. “My hope is that this will be a proverbial bridge-building exercise that enjoys support, whoever’s in charge.”

In the meantime, many states are just hoping they receive the funding they’re due. In North Carolina, the state’s transportation department is still figuring out precisely what its red-wolf crossings will look like and how many to build. (Although its grant application included a conceptual map with potential passage locations, a spokesperson from the agency said that “no additional analysis” has since been conducted.) But that planning and implementation can’t take place until the federal government releases money to the state. “NCDOT has yet to receive any guidance on the status of the Wildlife Crossing Pilot Program,” the spokesperson told Vox in an email. 

The fate of that funding could mean the difference between life and death, both for red wolves and the many other species that call the Alligator River refuge home. 

In August 2024, Wildlands Network launched daily roadkill surveys along US 64, cruising the highway and counting dead deer, bears, snakes, turtles, otters, bobcats, and other critters. In February the researchers counted their 3,000th animal — and though the survey hasn’t yet documented a dead red wolf, it seems only a matter of time. In an email, Sutherland said that federal turmoil was likely to “induce some delays” in building crossings, “which is sad for the wolves and other wildlife.”

Delays are the one thing red wolves can’t afford. 

Fifty miles east of Seattle, a bridge crosses a steep stretch of Interstate 90 known as Snoqualmie Pass. This is no ordinary bridge, meant for automobiles or pedestrians. Covered in topsoil, boulders, and seedlings, it is intended to convey wild animals from one side of the highway to the other — and it’s working. 

Since 2018, when the bridge opened and the first animal, a coyote, scampered over the six lanes below, the structure has carried creatures as large as elk and as small as toads. And it should attract even more users as the seedlings grow into trees and animals acclimate to its presence. 

“As we get more shade, it’s going to be different,” Patty Garvey-Darda, a Forest Service wildlife biologist, told Vox during a recent visit to Snoqualmie Pass. “Hopefully someday we’ll see the exact same species up here as we see in the forest.”

The Snoqualmie Pass bridge is one example in a broader category of infrastructure, known as wildlife crossings, that help animals circumvent busy roads like I-90. Crossings come in an array of shapes and sizes, from sweeping overpasses for grizzly bears to inconspicuous tunnels for salamanders. A body of research demonstrates that crossings can reconnect fragmented wildlife populations, while protecting human drivers and animals alike from dangerous vehicle crashes. “This structure is paying for itself because of the accidents we haven’t had,” said Garvey-Darda, as trucks roared by 35 feet below.

The construction of such crossings has never been more urgent. Roadkill rates have risen over the past half-century; today, around 12 percent of North American wild mammals die on roads. And new satellite-tracking and genetic technologies have revealed subtler harms. Busy interstates prevent herds of elk and mule deer from migrating to low-elevation meadows in winter, occasionally causing them to starve. In California, freeways have thwarted mountain lions from mating, leaving the cats so inbred that they’ve fallen into an “extinction vortex.” Wildlife crossings allow animals to find food and each other across sundered landscapes, and help them access new habitats as climate change scrambles their ranges.  

But despite crossings’ benefits, they remain scarce in the US. Around 1,000 wildlife crossings currently dot America’s 4 million mile road network. (For comparison, the Netherlands’ road system is only 2 percent as large but boasts over 600 crossings.) The reason for their rarity? Money. The Snoqualmie Pass bridge cost $6.2 million, and even humble turtle tunnels can run up multimillion-dollar price tags. This kind of expense explains why wildlife crossings were once a punching bag for some conservative politicians, who decried animal passages as government waste. 

Now that’s beginning to change. Earlier this month, the House passed the INVEST in America Act, a $1.2 trillion infrastructure bill that President Joe Biden is expected to soon sign into law. The bipartisan package earmarks billions of dollars in funding for highway maintenance, broadband internet, and airport upgrades — as well as $350 million for animal-friendly infrastructure like bridges, underpasses, and roadside fences. Although that provision is a tiny slice of the bill, it’s easily the largest investment in wildlife crossings in national history. 

These innovations are not only wildly effective at preventing roadkill, they’re also an underappreciated way to protect people. Hundreds of Americans die annually in car crashes with animals, and tens of thousands more are injured. “Whether it’s human safety or habitat connectivity or fiscal responsibility, there’s something in this bill for you,” said Renee Callahan, executive director of ARC Solutions, a group that studies and promotes crossings. “This has become a staunchly bipartisan issue.”

When the US interstate highway system was constructed more than half a century ago, ecosystems were damaged in ways we’re only now beginning to fully understand. Wildlife crossings and other animal-friendly infrastructure help mend that damage, and accommodate the creatures whose lives our highways have disrupted. Even within a bitterly divided Congress, it’s a rare area of consensus. One of the few things uniting some fiscal conservatives with climate-concerned Democrats is a literal bridge. 

How wildlife crossings went mainstream

Roads have few equals as a destroyer of animal life. Vehicles claim more wild terrestrial animals — perhaps more than a million per day in the US alone — than any other form of direct human-caused mortality, like hunting, oil spills, or wildfires. And it’s not just common critters like squirrels that get flattened (though we should worry about their welfare, too). At least 21 species are imperiled by cars in the US, and one recent study found that collisions may soon wipe out globally threatened creatures like maned wolves, brown hyenas, and leopards. We are, quite literally, driving some of the world’s rarest animals to extinction.  

For more than half a century, countries have attempted to solve this problem using wildlife crossings. France constructed the world’s first crossings, known as passages à faune, in the 1950s, followed by Germany and the Netherlands. During the 1970s and ’80s, a handful of American states, including Wyoming, Florida, and New Jersey, built their own crossings. Many showed promise: After a 100-foot passage was installed beneath I-70 in Colorado, for instance, hundreds of mule deer trotted through each summer. 

Yet crossings were slow to catch on in the US, for several reasons. Few states rigorously collected data on animal collisions, masking the problem’s severity. Some early structures were poorly designed or monitored, casting doubt on their efficacy. And even when agencies did document successful crossings, tight budgets rarely had room for more. “The unfortunate thing to date is that the most effective solution is also the most expensive,” wrote one California official in 1980. 

Over time, though, collisions became impossible to ignore. As human populations grew, traffic spiked in rural areas. Meanwhile, elk, bear, moose, and especially deer were bouncing back after centuries of exploitation. When speeding cars struck these hefty mammals, the crashes could be catastrophic for both parties. In 1995, researchers estimated that deer collisions caused 29,000 injuries and around 200 human deaths every year in the US. Animal crashes had become a public safety crisis. 

In 2005, Congress ordered the Department of Transportation to study the situation. Its report, published three years later, put some firm figures on the issue. The authors tallied all the expenses of a crash — the hospital bills, the vehicle damage, the value of the animal itself, and so on — and found that the average deer strike dinged society more than $6,000. Moose and elk were even pricier. All told, animal crashes were estimated to cost America over $8 billion a year.   

Against that backdrop, wildlife crossings were no longer viewed as frivolous expenditures, but vital public safety measures. In Wyoming, underpasses on Highway 30, paired with roadside fencing that guided animals toward them, cut mule deer collisions within a critical migration corridor by more than 80 percent, offsetting construction costs in just five years. In Arizona, underpasses and fences prevented enough elk crashes to do the same. 

New technology advanced the cause, too. Motion-activated cameras snapped high-quality photographs of animals moving through crossings, winning over skeptics, says Patricia Cramer, an ecologist who has studied crossings in Florida, Utah, and other states. “We could finally show the engineers that structures work,” she said. “Suddenly, they believed us.” 

Money for animal infrastructure has been hard to come by — until now

As wildlife crossings proved their worth, transportation agencies took a new interest. Highway acts in 2012 and 2015 expressly allowed states to spend federal dollars on wildlife infrastructure. New overpasses and underpasses popped up, particularly in western states like Wyoming and Montana, where deer and elk followed predictable migration routes that highways happened to bisect. Their approval ratings soared, too: One poll found that more than 90 percent of voters in Nevada — hardly a state that habitually embraces government interventions — were in favor of more crossings.

But crossings remained underfunded. Wildlife projects drew from the same pots as basic transportation needs, like lane repaving and highway repairs. Pitted against America’s crumbling infrastructure, animals got short shrift. (This was especially true for small species that didn’t endanger drivers — it’s likely no one has ever totaled their truck by slipping on a salamander, for example.) In 2013, when researchers asked nearly 500 officials why crossings weren’t more common, two-thirds chalked it up to money.

In the face of chronic fiscal shortfalls, some states got creative. Colorado allocated lottery revenue. Wyoming sold specialty license plates. In California, where engineers will soon break ground on a massive bridge for mountain lions, the conservation group National Wildlife Federation solicited private donations. (Leonardo DiCaprio was an early contributor.) But these revenue streams were piecemeal and unreliable, and many otherwise worthy crossings never got built. 

In 2013, road ecologists began to discuss securing more permanent funds. Scientists at the Center for Large Landscape Conservation, ARC Solutions, and the Western Transportation Institute wrote policy papers, met with congressional aides, and hammered out the basic framework for wildlife-crossing legislation. As the proposal developed, it gained supporters. Animal welfare groups like the Humane Society backed crossings to reduce wildlife deaths and suffering. Conservation organizations like the Wildlands Network touted crossings as a way of stitching up fragmented ecosystems. Even pro-hunting organizations trumpeted the restoration of healthy deer and elk herds as a selling point. 

“We use the lingo ‘win-win’ a lot, but in this case this was truly a win-win-win-win,” said Susan Holmes, federal policy director for the Wildlands Network. “Almost everyone could see the value in this.” 

With backing from hunters and highway safety advocates alike, animal-friendly infrastructure racked up unlikely congressional support. In a 2019 hearing on crossings, Sen. John Barrasso, a Republican from Wyoming and a former surgeon, said that he’s taken care of patients injured in collisions with wildlife. “It happens every year,” he said. Although Barrasso has a history of impeding climate-friendly initiatives — and a 7 percent lifetime score from the League of Conservation Voters — he included a wildlife crossing program in the highway bill that he sponsored later that year. (That version of the bill never passed.) Crossings also garnered support from Shelley Moore Capito, a Republican senator who chairs the chamber’s Environment and Public Works Committee — perhaps because Capito’s home state of West Virginia leads the country in deer crashes.  

The years of lobbying paid off this month, when the $350 million wildlife-crossing provision made it into the final infrastructure bill — the largest federal public works program since President Dwight D. Eisenhower kick-started the interstate system in the 1950s. (Thirteen GOP House members and 19 senators voted for the bill; despite Barrasso’s affinity for crossings, he wasn’t one of them.) The funding will be disbursed through a five-year competitive grant program, through which states, Native tribes, and other entities will submit proposals for new crossings within their jurisdictions. Now animals will have a separate pool of money from which officials will be able to draw. 

“This is finally approaching a scale that’s needed nationwide,” said Rob Ament, road ecology program manager at the Western Transportation Institute. “We can’t treat every mile of highway, but we can take care of a lot of the areas that are seriously affecting wildlife populations.”

The future of wildlife crossings is mobile

The new funding comes at a crucial moment. As the climate warms, it’s imperative that animals are able to move freely around landscapes. Think of moose shifting their ranges northward to escape infestations of hungry ticks, or bears fleeing wildfires intensified by drought. Crossing structures allow these creatures to navigate roads in search of novel habitat. 

Then again, crossings only go so far: An elk migration corridor might drift northward over decades, but a bridge or tunnel can’t follow. At least, not yet — but that, too, may change. 

According to the Infrastructure Investment and Jobs Act, the wildlife crossing program will prioritize structures that incorporate “innovative technologies” and “advanced design techniques.” Among those techniques, says Callahan, might be the use of fiber-reinforced polymer, or FRP, a plastic that’s lighter and stronger than regular concrete, and should soon be cheaper as well. The Western Transportation Institute and the California Department of Transportation are currently designing America’s first FRP wildlife bridge, and experts say that future iterations could someday be modular and mobile, capable of being disassembled and relocated in response to changing animal movement patterns. “That would be a game changer,” Callahan said. 

As exciting as all that may be, it’s important to remember that the new funding for wildlife crossings is merely a good start. While $350 million may sound substantial, it is, as Cramer puts it, “decimal dust” compared to national transportation budgets. It’s also a fraction of what’s ultimately needed: According to one recent report, it would cost $175 million to deal with roadkill hot spots in California alone. What’s more, wildlife crossings can’t do much about traffic noise, salt pollution, stormwater runoff, or many of the other byproducts of roads — some of which will, ironically, be exacerbated by the infrastructure bill, which allots millions to highway expansion projects. And all the crossings in the world won’t help unless we get better at protecting the habitats that animals must move between. 

“We can build a bridge,” said Matt Skroch, project director for public lands and rivers conservation at the Pew Charitable Trusts, “but let’s not build a bridge to nowhere.”

Correction, November 12, 10:40 am: A previous version of summary text for this story misstated the amount of Infrastructure Investment and Jobs Act funding that is related to wildlife crossings. It is $350 million.