An Engineering Wonder, a Bike Commuter’s Dream: The Cal Park Hill Tunnel

Posted 08/12/14 by Katie Harris in Building Trails, Success Stories

Photo © Streetsblog USA

The Nonmotorized Transportation Pilot Program (NTPP) was created in 2005 under the federal transportation act, SAFETEA-LU. This program allocated $25 million each to four communities across the U.S. for bicycle and pedestrian infrastructure and programs. Between 2009 and 2013 alone, the program was responsible for averting 85.1 million vehicle miles traveled and 34,629 tons of CO2 emissions. Each week during the month of August, we will highlight one of these communities, focusing on the lives that were positively impacted by NTPP. Check out last week’s post on Minneapolis, here.

Christina Toms’ commute is the definition of multi-modal. From her front door in Fairfax, Calif., she hops on her bike and cruises down to the Larkspur ferry terminal. From there, she catches the ferry that brings her across the bay to the city of San Francisco. 

That commute is possible in large part to the Cal Park Hill Tunnel, an engineering triumph that makes the vital connection between San Rafael and Larkspur in Marin County, Calif. 

Christina Toms on the San Francisco Bay Ferry © Christina Toms

According to Toms, the Cal Park Hill Tunnel is connecting communities in ways that were never possible before. “The tunnel has made it so much more feasible to ride,” affirms Toms. “It’s far more direct, and it’s so much safer than before.” 

The Cal Park Hill Tunnel opened in 2010, but its story began more than a century earlier. Built in 1884 and widened in 1924, the structure helped the railroads move freight along the 300-mile-long corridor between Tiburon to the south and Eureka to the north. During the lumber boom in Northern California, the railroad, and the tunnel that brought goods to its southern terminus, was used heavily. While lumber was certainly a large part of the railway’s load, trains carried a variety of freight over the years, but the railroad ended all service in 1985, and the tunnel sat empty. In the late 1980s, a partial collapse at the south end signaled the tunnel’s disintegration, and after a fire in 1990, approximately 20 percent of the tunnel was collapsed, with the remainder in various states of disrepair. It was time for the tunnel’s renaissance

A pivotal point in the structure’s recovery came in 2001, when bike and pedestrian advocates, led by the Marin County Bicycle Coalition (MCBC), fought off a proposed parking lot for the Golden Gate Bridge to be constructed in front of the sealed tunnel entrance. This was a major victory, because it validated the efforts that had been undertaken up to that point. The vision of resurrecting the Cal Park Hill Tunnel was strong, and nine years and a tremendous amount of work later, on a foggy day in December 2010, the tunnel was reopened. The excitement was palpable as the dream was finally realized.

“It is amazing that we were able to retro fit and reuse this piece of infrastructure,” Toms says. As an engineer, Toms has an appreciation for the tunnel retrofit, particularly because of California’s geotechnical conditions. It is a huge undertaking to rehabilitate a partially collapsed tunnel; it is an additional challenge to make it seismically safe in a state known for ground-rattling earthquakes. 

Before the tunnel was accessible to pedestrians and bicyclists, Marin County resident Carlos Rico says he traveled to work on segments of road on which he felt unsafe. “The traffic is pretty scary on those stretches, even for an experienced rider,” explains Rico. But with the tunnel in action, he can avoid those dangerous segments. “Yes, the tunnel saves me time, but far more importantly, it is a much safer route,” he says.

It is undeniably an asset to bike commuters, but according to Toms, the Cal Park Hill Tunnel serves more subsets of the community than just those who ride to work. “Every day, I see the whole range of people using the tunnel,” she reports. From speedy commuters in spandex on carbon fiber bikes, to folks in jeans and sneakers on their way to work, to people who use the path for fitness, Tom says more people discover and use the connector each day. “I see lots of pedestrians, strollers and families on the way to the movies or the farmers’ market,” adds Toms.

Andi Peri, advocacy director at MCBC, explains that the diversity of users is not limited to their mode of travel. Many people of Mexican and Central American descent use the structure daily to get to work, exercise, or spend time with their families. Rico echoes this sentiment. “The tunnel is used by a diverse and wide variety of people, for both work and play,” he says.

A safe, multi-modal commute for many Marin County residents is now a possibility, but the structure is unique in the other mode it will accept—that of light rail. The tunnel was specifically constructed in anticipation of the inclusion of theSonoma-Marin Area Rail Transit (SMART). While the walkers, bikers and other non-motorized users will share the same structure with SMART, the tunnel separates the user groups completely, a “tunnel within a tunnel,” of sorts.

While SMART is not yet ready to bring service through the corridor, the planning has been done and the capacity is in place. It is just one segment of Marin County’s multi-modal vision, but to users like Toms and hundreds of others, it makes all the difference.   


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