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The Devil’s Slide Trail - How a State Highway Became a Scenic Paradise

Posted on Tue, Mar 17, 2015

By Jonathan Berlin, MESM

This article was originally published in the APA California Northern News Newsletter (April 2015 edition). The original article can be read here.

1953 slideCalifornia has several trails to hell: the Devil’s Backbone Trail in the San Gabriel Mountains (precipitous falls to either side), the Devils Kitchen Trail in  Lassen Volcanic National Park (boiling and hissing mud pots), and the Devil’s Slide Trail (treacherous landslides). The last trail, which hugs a spectacular rocky coastline south of Pacifica in San Mateo County, is a recent addition to this list. Since its grand opening on an abandoned stretch of State Route (Highway) 1 in March 2014, the 1.3-mile Devil’s Slide Trail has already become the most popular destination managed by the San Mateo County Parks Department. Visitor counts show that an average of 1,100 people come to the trail per day, which amounts to more than 400,000 people per year. This level of interest greatly exceeds the County’s early expectations of more than 60,000 people per year. Sam Herzberg, a senior planner at the Parks Department, believes that as awareness of the Devil’s Slide Trail grows, it “might become a national or international attraction.” This success story in-the making did not, however, come easily. It depended on a controversial re-routing of Highway 1 that involved decades of political strife among planners, engineers, and activists.

Bedeviling the engineers

Since the late 19th century, engineers have waged war against the Devil’s Slide formation. The first County road was abandoned in 1914, due to rock falls, and replaced with a winding bypass route to the east over San Pedro Mountain. In 1906, the Ocean Shore Railroad between San Francisco and Santa Cruz was under construction when the Great San Francisco Earthquake caused the Devil’s Slide section to plunge into the ocean. Following in the shadow of these doomed routes, Highway 1 opened between Pacifica and Half Moon Bay in 1937. Landslides at the Devil’s Slide have resulted in road closures every decade since, some lasting months at a time. In the worst instance, a landslide during heavy winter rains in January 1995, the roadbed dropped about 30 feet, says Herzberg, and Highway 1 remained closed for 159 days. To stabilize the roadway, engineers installed “a 50-foot-long metal girder holding up the road” and bolted a steel net to the slope above to catch detached rocks. Despite these repairs, the highway remained vulnerable to shifting rocks. The landslide-prone area extends from an elevation of about 900 feet down to at least sea level at the coastline, with a width of about 4,000 feet, according to a guidebook published by the National Association of Geoscience Teachers in 2001. Given the long-term instability of this area, Caltrans considered its repairs to be stop-gap measures until a bypass route for Highway 1 was selected and built.

Political struggle over bypass routes

As early as 1958, the California Division of Highways determined that the Devil’s Slide should be abandoned and began studying alternate routes. The California Highway Commission approved a six-lane overland bypass route in 1960 that would have required extensive grading on Montara Mountain. Between 1969 and 1972, Caltrans acquired 55 percent of the right-of-way needed to build the adopted bypass. However, a coalition of environmental advocacy groups sued Caltrans in 1972 for not preparing an Environmental Impact Statement, as required by the recently enacted National Environmental Policy Act for federally led or funded projects. This lawsuit halted the construction contract for the bypass and directed Caltrans to study environmental impacts. An overland bypass remained the preferred alignment until the catastrophic landslide of 1995 motivated the County Board of Supervisors to set up an independent panel of technical experts to identify the best alignment. Although the panel recommended building a pair of tunnels through San Pedro Mountain, the Board decided in favor of an overland route. But San Mateo County citizens took matters into their own hands and approved Measure T in November 1996 to amend the County’s Local Coastal Program to select the tunnels as the preferred bypass. The initiative also required that a separate trail for pedestrians and bicyclists be provided outside the tunnels.

Birth of the trail

K RailsThrough the tunnels’ permitting process under the California Coastal Act, the County agreed to assume responsibility for the Devil’s Slide Trail. As a condition of approval of the Coastal Development Permit to build the tunnels, approved in May 2004, the County would accept the deed to the old roadway and improve it for non-motorized transportation. The permit also required that Caltrans build parking lots at the future northern and southern trailheads, says Herzberg. The County’s commitment to building the Devil’s Slide Trail was effectively an unfunded mandate. By the time that the Board of Supervisors approved $2 million for this purpose in the County’s 2012–2013 budget, almost a decade later, Herzberg notes that a whole new set of Supervisors had been elected and the expense had to be justified. Once the tunnels opened in March 2013, the Parks Department used this funding to coat the abandoned roadbed with a polymer to smooth out the surface for bicyclists, to re-stripe it for two six-foot-wide bike lanes and an eight-to-12-foot pedestrian path, and to erect signs and fencing. Two scenic overlooks also were constructed, with benches and coin-operated telescopes. “I think they did a fantastic job with the benches and lookout points,” says Anthony Ricarte, a resident of Pacifica, who walked the trail on February 15 with Monika Hanson and his two-year-old daughter, Sophia.To improve the aesthetics of the trail, the Parks Department painted three-foot-high concrete barriers known as K-rail in a tan earth tone that approximates exposed bedrock. The inner K-rail serves as a barrier to protect the trail from small falling rocks, says Carla Schoof, a community programs specialist with the Parks Department. Structural improvements dating to the 1995 landslide remain visible. To Monika Hanson, a first-time visitor from Walnut Creek, old elements such as the series of giant bolts supporting the rock face at Devil’s Slide, serve as points of historic interest.

Scenic views

PowBut visitors most appreciate the opportunity to enjoy scenic views of the coastline and exposed bedrock. Jeffrey Chang, a South Bay resident and founder of a high-tech start-up, remembers when the Devil’s Slide was open for motorists. “Sometimes we’d stop on the side of the road illegally, just to enjoy the view,” he laughs. After taking his 13-year-old son Andrew to a soccer tournament in Pacifica this February, Chang was excited to find the route open as a trail. Chang brought his entire family to walk the trail, including Andrew, still wearing soccer cleats, and his parents visiting from Taiwan. An avid hiker who has explored Yosemite, Mount Diablo, and other parks, Chang says that the view here is “one of the best” and reminds him of the rocky northeastern coast of Taiwan. “It’s the pow of the view,” agrees Wendy Antipa, from San Francisco. On a clear day, her husband Greg notes, it is possible to see the Farallon Islands, about 25 miles off the coast, and Point Reyes to the north. The Antipas were visiting the Devil’s Slide Trail “to size up the site for a geology walk” for the Retirement Association at San Francisco State University. The southern end of the trail features exposed granite from Montara Mountain, while road cuts at the northern end reveal rough sedimentary layers of shale and sandstone.

Trail ambassadors

Chang FamilyAs a consequence of its popularity, parking at the Devil’s Slide Trail can get competitive. About 40 parking spaces exist at the northern and southern trailheads combined. Immediately after the trail opened, the parking lots filled and visitors resorted to parking on Highway 1, where California Highway Patrol officers ticketed them, says Herzberg. Anthony Ricarte adds that “the parking is kind of a nightmare” on weekends. To improve parking capacity, the Parks Department is working with the Golden Gate National Recreation Area and the California Department of Parks and Recreation. This partnership may lead to shared parking nearby, with a shuttle running to the Devil’s Slide Trail, says Herzberg. Currently, a free weekend shuttle runs from Pacifica to the trail, and SamTrans Route 17 stops at the trailhead, but Herzberg says that there is a lack of awareness about these transit options. The trail’s lifespan also depends on the stability of the Devil’s Slide. Heavy equipment operated by the Parks Department can clear minor rockslides from the trail. But in the event of a catastrophic landslide, if the trail “goes off into the ocean, it’s just gone,” says Schoof. The Parks Department does not foresee restoring the trail in that case. Herzberg hopes that the trail will last longer than it would have as a motorized route because of the lighter impact of non-motorized users. In the meantime, the project has underscored the popularity of trails as a means to provide access to valued landscapes and open spaces. And the Devil’s Slide Trail has become an active interpretive site informing Californians about coastal geology and our storied state highway system.Because the Parks Department anticipated high use of the Devil’s Slide Trail – if not 400,000 people per year – and lacked staffing to fully serve the completed trail, it created a Trail Ambassadors program. To date, 50 members of the public have registered as Ambassadors, receiving training in radio use, the history of the trail, and environmental features. In the field, they report trail conditions, answer visitor questions, and communicate with park rangers, says Schoof. Ambassadors are present on the trail on all weekends, some weekday mornings, and “when there’s a really good sunset,” says Schoof. One benefit of this program is the skills and knowledge base that local citizens bring, including expertise on native plants and birds. 


JonAuthor Jonathan Berlin is an Associate Environmental Planner at Rincon Consultants, where he serves as a lead analyst and project manager for trails and open space planning projects. Jon also specializes in CEQA/NEPA review and noise impact studies. He holds a Master in Environmental Science and Management (MESM) from UC Santa Barbara and a BA in Journalism from the University of Maryland. You can reach him at

Topics: Caltrans, American Planning Association, Devil’s Backbone Trail, Lassen Volcanic National Park, San Mateo County, State Route 1, Highway 1, Pacifica, APA, Transportation, active transportation, San Gabriel Mountains

Around the Bay in 500 Miles: Regional and Local Planning for the San Francisco Bay Trail

Posted on Tue, Sep 2, 2014

By Jonathan Berlin, MESM

This article was originally published in the APA California Northern News Newsletter (September 2014 edition). The original article can be read here.

CaptureStarting at 5:30 AM on Tuesdays and Thursdays, Richard Yan bikes from San Francisco’s Mission District through a patchwork of marshes, parks, golf courses, and local roads to his office in Mountain View. As part of the SF2G group, kicked off by Google employees in 2005, Yan rides in a pack with other members of the South Bay’s high-tech sector. “It is quite a nice way to start your morning and see the sunrise,” Yan says of his 48-mile ride. The development of the San Francisco Bay Trail over the last 25 years has enabled many such commutes by bicycle, along with better access to recreation, on a network of trails ringing the Bay. When the Association of Bay Area Governments (ABAG) adopted the Bay Trail Plan in 1989 to guide the development of this network, the agency inherited about 100 miles of preexisting trails but envisioned 500 miles total. Today, the Bay Trail Project at ABAG has completed 338 miles, including large chunks of a primary “spine trail” and spur trails toward the shoreline. Based on this success, the APA’s Northern Section and APA California both honored the San Francisco Bay Trail with a 2014 Planning Landmark Award of Excellence, signifying a historically significant effort that opened new directions in planning over at least a quarter century. This story explores the contributing factors to development of the Bay Trail, emerging challenges, and lessons for regional and local planning.

Local partners for regional planning

Moving from a grand regional vision to local implementation, the Bay Trail Project’s first step was to lobby all nine Bay-Area counties and 47 shoreline cities to incorporate the Bay Trail into their general plans, local trail plans, and specific plans for waterfront development.

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All local jurisdictions now unanimously support the Bay Trail. When shoreline developments are proposed, Bay Trail staff retains a role during the CEQA public involvement process in "elevating public access as a priority at the local level to help further the regional goal of completing a continuous Bay Trail,” says Laura Thompson (right), who has managed the Bay Trail Project since 2004.

Beyond enlisting cities and counties, the Bay Trail Project has partnered with the Trails for Richmond Action Committee (TRAC), the only citizen-led group solely focused on implementing the Bay Trail, since its inception in 1999. “When we formed TRAC, Richmond describe the imagehad only 12 miles of Bay Trail built,” says TRAC chair and co-founder Bruce Beyaert, “and they were fragmented.” To put this into context, Richmond has 32 miles of Bay frontage — or “more shoreline than most cities can shake a paddle at,” as a current Chevron advertisement boasts. With a growing economy and many developments proposed on Richmond’s shoreline at the time, Beyaert saw a “window of opportunity” for improving connectivity. TRAC found a niche preparing grant applications on behalf of the City of Richmond, bringing in more than $7 million for Bay Trail segments, Beyaert says. Today, Richmond has more than 32 miles of Bay Trail completed, including more than four miles of shoreline trail not envisioned in the original plan. “The joke at ABAG is they want to clone TRAC!” says Beyaert (left).

Leveraging permits

A wave of grassroots environmental activism in the early 1960s led the State legislature to create the San Francisco Bay Conservation and Development Commission (BCDC), whose mission is to minimize fill in the Bay while maximizing responsible public access.

With its goal of improving public access to the Bay, BCDC is a natural ally in implementing shoreline trails for bicyclists and pedestrians. The agency has an expansive area of jurisdiction, including but not limited to the Bay’s open waters, marshes, mudflats, and the first 100 feet inland from the shoreline. In this area, BCDC’s permitting authority over the subdivision of property, grading, construction, and substantial changes in use can compel  project applicants to provide right-of-way for the Bay Trail.

“No agency is going to do it out of the goodness of their heart,” Thompson acknowledges, “because they just don’t have the funding for it.” But BCDC permits have provided the necessary leverage to close major regional gaps in the Bay Trail.

Following the catastrophic 1989 Loma Prieta earth- quake, Caltrans has conducted seismic retrofits of bridges in the Bay Area, triggering the need for BCDC permits. As a condition of obtaining these permits, Caltrans has granted right-of-way for Bay Trail segments on the Carquinez and Benicia/Martinez bridges and the new east span of the San Francisco-Oakland Bay Bridge. Today, five of the Bay Area’s seven bridges provide access to bicyclists and pedestrians, including preexisting access on the Golden Gate and Dumbarton bridges.

Conflict resolution through sciencedescribe the image

When Rick Parmer (right) joined the Bay Trail’s Board of Directors in 1990, bringing scientific knowledge as a naturalist for the California Department of Fish and Wildlife, controversy arose over the impacts of trail use on shorebirds and waterfowl feeding in mudflats.

To settle the question, the Bay Trail Project and multiple partners funded a three-year Bay Trail Wildlife & Public Access Study, led by researchers at San Jose State University. Thirty-two observers dispersed to three different shoreline sites in Marin County, San Mateo County, and Santa Clara County, and counted birds and trail users in paired plots with and without existing trails.

The preliminary results found no general relationship between human use of trails and the abundance or diversity of birds in foraging habitats at these locations. According to Parmer, this comprehensive study satisfied most people that shoreline trails would not significantly impair birds. Parmer believes that trail planning benefits from the objectivity of science. “You’re not just using your subjective, best professional opinion,” he says, but rather relying on evidence backed by statistics.

A broad supporting constituency

While the Bay Trail initially proved popular with recre- ational bicyclists and pedestrians, trail use diversified in response to social trends. In the last decade, Parmer has observed a surge in the number of bicyclists commuting on the Albany-Berkeley corridor. Thompson has witnessed increases in birdwatchers tracking the Pacific Flyway for migratory birds in the winter. And the rise of Internet- based social groups like SF2G has catalyzed growth in all types of trail users.

describe the imageAware of growing employee interest in bike commuting, corporations are beginning to support the Bay Trail. Google recently became the first corporation to fund a non-adjacent trail segment, Parmer says, seeing value in improving connectivity throughout the South Bay.

As with planning in general, public health is becoming a motivating concern in trail planning. Kaiser Permanente, the health care provider based in Oakland, is sponsoring a series of events to celebrate the Bay Trail’s 25th anniversary. The Bay Trail Project also is interested in appointing someone with expertise in public health to its board of directors, says Thompson.

Remaining challenges

In the effort to finish the 500-mile ring and protect existing trail access, leaders point to three main challenges: funding, feasibility, and climate change. The bulk of funding to acquire right-of-way and develop trails has come from State bonds for parks, wildlife, and open space; however, existing bonds are running out, and the future funding environment on a State level is uncertain, Parmer says.

Implementation of remaining Bay Trail segments along interstate highways also depends on funding from the federal Highway Trust Fund. But the roadway user fees that supply this fund are increasingly too meager to meet demand. In August, the U.S. Department of Transportation announced that the Highway Trust Fund is becoming insolvent. Congressional squabbling over reauthorizing the federal transportation program also endangers this funding source. “Reauthorization of the federal Highway Trust Fund is a huge issue,” says Parmer.

Filling the remaining gaps in the Bay Trail also tends to be less feasible because of the unwillingness of landowners or technical challenges such as bridge retrofits. “We’re down to the tough parts now” says Thompson. For example, to complete access across the Bay Bridge’s west span, between Yerba Buena Island and downtown San Francisco, could require a cantilevered structure attached to the existing span — with a cost of $500 million to implement. The Bay Area Toll Authority is in the initial stages of planning this path.

Then there’s sea level rise — the “800-pound gorilla,” as Parmer calls it. BCDC’s Living with a Rising Bay report from 2011 projects a 16-inch rise in water level by mid-century, accelerating to a 55-inch rise by the end of the century. For a shoreline trail, sea level rise poses a critical threat. Already, high tides — combined with storm surge — flood the Bothin Marsh segment in Mill Valley. Anticipating this problem, the City of Alameda and East Bay Regional Park District submitted a grant application in April to elevate and resurface a three-mile trail segment on Bay Farm Island.

As sea level rise progresses, shoreline communities have “some hard decisions to make in the next couple of decades,” Thompson says. They can either armor existing infrastructure or retreat from the shoreline. Whether trails remain fortified or shift inland, the Bay Trail Project wants to maintain public access.


JonAuthor Jonathan Berlin is an Associate Environmental Planner at Rincon Consultants, where he serves as a lead analyst and project manager for trails and open space planning projects. Jon also specializes in CEQA/NEPA review and noise impact studies. He holds a Master in Environmental Science and Management (MESM) from UC Santa Barbara and a BA in Journalism from the University of Maryland. You can reach him at

Topics: TRAC, Bay Conservation and Development Commission, BCDC, American Planning Association, San Francisco, San Francisco Bay Trail, Association of Bay Area Governments, ABAG, Trails for Richmond Action Committee, CEQA, APA, active transportation