The findings come as many Bay Area communities, particularly those along the coast, have limited options for residents seeking to escape fast-moving fires. The study analyzed data from some of the nation's most destructive wildfires and concluded that communities need more than six major evacuation roads to reduce the risk of deaths during emergencies.
"When you have six or more than six roads that in that emergency context there might be enough roads out that even if one burns over, for example or two burn over, you might have enough exists out to still be okay," said Caitlin Fong of the National Center for Ecological Analysis and Synthesis.
Researchers pointed to past disasters as examples of the dangers posed by limited evacuation routes.
In Lahaina, Hawaii, four evacuation routes proved insufficient during the 2023 wildfire that devastated the community.
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"Everything used to be here. It is no more," one resident said while describing the aftermath.
Similarly, a Los Angeles Times investigation into California's 2018 Camp Fire found that roads in Paradise were "only capable of evacuating one quarter of the population within two hours."
Paradise Mayor Steve Crowder said fallen utility poles further complicated evacuation efforts during the fire.
"The poles went down across evacuation routes and actually shut down roads so if you were heading in that direction and then you would have to turn around and find another way out," Crowder said.
The study's findings have particular relevance for the Bay Area coastline, where many communities rely on only a handful of roads for access and evacuation.
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Pescadero depends on Highway 1 to the north and south, along with Pescadero Creek Road. Half Moon Bay residents largely rely on Highway 1 and Highway 92.
"I'm guessing that people who live in Half Moon Bay are very aware of their road limitation," Fong said.
Concerns about roadway capacity were highlighted in December 2024, when a tsunami warning prompted an evacuation that led to significant traffic congestion along Highway 1.
Residents of coastal communities say limited access routes are a longstanding concern.
"The fact that there is only one way in and one way out, we talk about that a lot even with earthquakes and we say, we're on our own, we're an island," said Montara resident Barbara Dinnsen.
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The study acknowledges that constructing new evacuation roads may be impractical or impossible in many locations. Instead, researchers emphasize preparedness and local planning.
The Midcoast Community Council, which represents the unincorporated communities of Montara, Moss Beach, El Granada, Princeton-by-the-Sea and Miramar, regularly discusses evacuation concerns.
David Cosgrave, program manager for the Coastside Community Emergency Response Team, said residents should focus on measures that can improve safety rather than viewing the study as a reason for alarm.
"We can't build more roadways but we can clear the vegetation around them just so they are more 'defendable' and safe to drive if there was a fire that encroaches on the highway," Cosgrave said.
The study also recommends identifying refuge areas where people could shelter if evacuation becomes impossible.
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"That's clear of vegetation, a horse stable or a riding arena, a school, a wide area of the roadway, anything that is not near a lot of vegetation and fuel that can threaten them," Cosgrave said.
While coastal residents often point to fog as a natural defense against wildfire, researchers caution that climate change could alter historical fire patterns.
"We are lucky here for one main reason and it's our fog," Dinnsen said.
"As things also get drier and the climate warms, we're starting to see fires in places that we haven't necessarily historically," Fong said.
Researchers concluded that wildfire risks are evolving as the climate changes, making advance planning and evacuation preparedness increasingly important for communities with limited escape routes.