From Highway 101 to Monterey Road, traffic in Silicon Valley has become deadly for wildlife trying to move between the Santa Cruz Mountains and the Diablo Range. Now, a major project is underway to connect preserved open spaces in the South Bay and reduce dangerous crashes for drivers.
“Monterey Road is a death trap,” said Fraser Shilling, a researcher at UC Davis who studies how wildlife interacts with roads.
While trying to cross Monterey Road, for instance, a deer will often encounter a fenced median and, in its confusion, get caught in the flow of traffic, unable to escape.
That may change in the coming years.
The Santa Clara Valley Transportation Authority and its partners are set to begin designing wildlife crossings south of San Jose — a project likely to take years to complete and still dependent on securing construction funding.
“This is really the culmination of many, many years of land protection and advocacy work … that enable habitat restoration,” said Taylor Jang, senior Coyote Valley project manager at Peninsula Open Space Trust (POST), which spearheaded the effort. “We’re really excited to start this.”
Wildlife collisions are a deadly problem across the state. Vehicles kill thousands of wildlife every year in California. More than 40,000 deer are killed each year by drivers — around 10% of the state’s deer population and about twice as many as are killed by hunters, according to Shilling.
But it isn’t just wildlife that are affected. According to the California Highway Patrol, drivers are involved in thousands of crashes with animals every year, resulting in hundreds of injuries and sometimes even death. Shilling and his colleagues estimate those collisions cost Californians more than $1.6 billion between 2016 and 2023.
“This is a safety project as much as a wildlife project,” said Zahir Gulzadah, deputy director of VTA’s highway program. “We’re trying to avoid collisions as well as make sure our wildlife is safe.”
Coyote Valley, which stretches between San Jose and Gilroy, is a local hotspot for those crashes. While some culverts allow animals to pass beneath roads, if those structures are inaccessible or flooded, wildlife often attempts to cross on the highway instead.
A milelong stretch of Highway 101 over Coyote Creek ranks among the most expensive in the state when it comes to the cost of wildlife-related crashes, according to a 2021 UC Davis study.
POST, which is providing much of the funding and research to guide the project, monitored wildlife crashes along the corridor for years and identified multiple hotspots where animals were repeatedly killed, including near the intersection of Fisher Creek and Monterey Road.
While detailed design work is just beginning, VTA expects the project to include multiple undercrossings beneath U.S. 101 and Monterey Road focused on those hotspots between San Jose and Morgan Hill. Construction would involve building new crossings and retrofitting existing structures like culverts to allow animals to pass more easily, as well as extensive fencing — about 18 miles, according to Jang — on either side of the road to guide wildlife toward the crossings.
POST and its partners, including the Wildlife Conservation Fund, the city of San Jose and the California Wildlife Conservation Board, have raised enough to fund the design phase. But construction money has not yet been secured. Building the crossings, expected to begin in 2028, would cost an estimated $80 million to $90 million.
Jang said that given the long lifespan of the structures — estimated at 75 to 100 years — and the high cost of crashes, “these projects pay for themselves” by preventing collisions and reducing insurance and health care costs. He also said they offer “intangible benefits” to wildlife, ecosystem health and even traffic congestion caused by animal collisions.
The effort comes after years of land preservation on both sides of Coyote Valley. POST and other groups, including the Santa Clara Valley Open Space Authority, have spent millions acquiring a patchwork of properties to protect habitat for species ranging from mountain lions and American badgers to salamanders and frogs.
Coyote Valley also serves as a vital corridor between the Santa Cruz Mountains and the Diablo Range, but the highways and railroad cutting through the valley are putting that connection at risk.
Jang said there are already signs of isolation among local wildlife populations. Mountain lions in the Santa Cruz Mountains, for example, are showing evidence of inbreeding — a signal that the population is no longer mixing freely with others. Over time, that could threaten long-term survival and disrupt the broader ecosystem.
“If we do nothing, we’re headed to a bad place in terms of local ecology,” Jang said.
The crossings are designed to reconnect the lands on either side of the valley, allowing animals to migrate safely in search of food, shelter and mates.
Even though funding remains uncertain and ecological benefits may take years to emerge, Jang said the long-term payoff could be transformative.
“We’re hopeful that Coyote Valley looks a lot different in 50 years, in 100 years than it does today,” he said. “That’s the kind of timescales that we’re trying to impact.”
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