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Traffic & Road Safety Concerns

Traffic congestion on the San Mateo County coast is getting worse. It adversely affects the accessibility of visitors to the coast and the quality of life for residents. Although the San Mateo County coast has experienced less growth relative to the rest of the Bay Area, commute times and tourist traffic have steadily risen. With the onset of the 2020 Covid pandemic, tourist traffic has been heavier than ever before, and not limited to weekends, because people are seeking more outdoor activities. Rising seas and erosion are visibly impacting Highway 1 along the Midcoast south of the Lantos Tunnel and near Princeton Harbor. Both capacity and circulation are increasingly strained.

One Road - Highway 1 Dependency

The San Mateo County Midcoast is unique in that there is only one road in, through, and out. There are no alternate routes. There are no road expansion opportunities available in the foreseeable future. Residents, visitors and commercial vehicles are all served exclusively by Highway 1, a rural two-lane arterial highway through the Midcoast that provides regional connections from Half Moon Bay / Santa Cruz (south) to San Francisco (north). 

Local residents are completely reliant on Highway 1 for access to health services, schools, shopping, etc. School and job commuters rely on Highway 1 since most commuting is by private vehicle. For locals, alternative modes and public transportation to reach goods and services are very limited. 

The coastal area is a very popular destination for tourists who also are dependent on private vehicles as limited public transit for visitors makes it impractical. Half Moon Bay estimates that three million people visit the area annually. Peak weekday and weekend traffic is regularly gridlocked. Weekend peak traffic congestion appears unavoidable and is expected to get worse.

Public Safety - Current Conditions

Current highway conditions include congestion, a lack of designated areas/trails for cyclists and pedestrians, a lack of crosswalks, and over-run visitor parking areas. Highway 1 speed limits are as high as is normally appropriate for a rural highway. However, the level of high-speed traffic has resulted in safety concerns and significant delays for cross-traffic as well as unsafe conditions for cyclists and pedestrians. 

Neighborhood Road Safety

Road safety is a key concern, as our semi-rural coastal character features roads that are narrow and lack sidewalks. Although detours all lead back to the highway, when congestion is heavy, traffic is pushed and/or rerouted to these neighborhood streets through apps like Waze. Montara and Moss Beach have already experienced congestion on small neighborhood roads over the last few years, raising safety concerns for pedestrians and cyclists including children walking and biking to school. 

Public Safety - Emergency Situations

Congestion can severely impact the safety and response time of emergency vehicles. On the Midcoast, any serious traffic accident or emergency situation on Highway 1 can shut down the highway, leaving residents and visitors stranded. In 2019, the Lantos Tunnel was closed unexpectedly for almost 20 hours with poorly managed information. In early 2023, severe weather simultaneously closed portions of both Highway one and Highway 92, raising even more concerns regarding emergency and evacuation management. How does one get to the hospital in an emergency if the only highway we rely on is gridlocked? What will happen if the Lantos Tunnel is closed unexpectedly?

Moss Beach

Current traffic problems (before Big Wave or MidPen developments in Moss Beach)

AM commute on Northbound HWY 1 in Pacifica

Saturday Afternoon in Montara

Beginning in 2019, wildfire risk became a new and real concern as PG&E imposed several power outages lasting 24+ hours, resulting in total traffic congestion and temporary closures of many operations. More mandated blackouts are predicted over the coming years as necessary to reduce wildfire risk and to manage energy usage. 

In the event of an actual natural disaster, such as wildfire, options are severely limited if evacuation becomes necessary. In August 2020, dry-lightning caused multiple wildfires throughout California, including the San Mateo coast south of Half Moon Bay. Equipment as well as manpower was strained to the point of breaking down rescue plans. In early 2023, severe atmospheric rivers closed both highways periodically due to fallen trees, flooding, and accelerated highway erosion. Climate change is a reality. The possibility of an earthquake is another concern in terms of road infrastructure. How will the coast manage?


Visitors and residents of the Midcoast, as well as Half Moon Bay, are heavily reliant on Highway 1 and its circulation capacity. Our fixed infrastructure is already strained. Expanding Highway 1 through the scenic areas along Montara Beach to Lantos Tunnel and at the south end of HMB is prohibited by the Coastal Act. Little can be gained by adding lanes in between.

Highway 1 and Road Management

Management of California highways is handled by Caltrans, including responsibility for improvements. As an unincorporated area, the San Mateo County Midcoast’s planning and permitting of development are the responsibility of the County. The Coastal Act, supplemented through each coastal area’s Local Coastal Program (LCP) and administered by local governments, provides policies to guide development including development of public works. Changes to the highways providing access to the coast are subject to coastal commission review.

The County recently completed a Comprehensive Transportation Management Plan, also known as “Connect the Coastside,” approved by the Board of Supervisors in July 2022. This plan covers all the unincorporated areas along the San Mateo coast with a focus on Highway 1 and affecting the Midcoast in particular. The plan identifies priorities and alternatives for transportation improvements, however, CalTrans and the other affected public agencies need to embark on lengthy coordinated studies to evaluate the alternatives while the County pursues funding options. The plan includes estimated timelines that project all significant improvements Beyond 2040.

No expansion of roadway capacity

There are no plans to expand roadway capacity under consideration, and prior studies have demonstrated that expanding capacity induces more demand which in turn could potentially overwhelm the capacity of other public infrastructure. Growth management limitations must be implemented to offset limited highway capacity.

Who is looking at the big picture?

The big picture of building impacts needs attention and coordination. The community remains very concerned that development of approved and proposed large-scale housing and commercial projects, such as Big Wave, The Dunes, and Cypress Point, and increasing residential density of the Midcoast will compound these road problems. These building projects must all be considered together to understand how the infrastructure for all public works will be impacted.

Traffic & Safety Now: Our Recommendations

After several years of studies, even simplified recommendations for critical traffic and safety measures remain unimplemented. These ideas for improvements come from various studies of existing issues. Our list for resolving some critical points in the near term include:

1. Reduced Speeds and Acceleration Lanes  

In Moss Beach and Montara, a combination of reduced traffic speeds and acceleration lanes for cross traffic at a few intersections could provide near-term improvements to circulation and safety at low cost. 

  • Widen Cypress Avenue and California Avenue approaches at Highway 1

  • Stripe separate lanes for right and left turns onto Highway 1 from Cypress Avenue and California Avenue

  • Add acceleration lanes on Highway 1 for left turns from Cypress Avenue and California Avenue.

2. Safe Pedestrian Crossings

  • Add a bi-modal bridge from the north end of Carlos Street to the Montara Lighthouse. This would provide a safe passage across Highway 1 for cyclists and pedestrians. This bridge would have the added benefit of connecting the Parallel Trail from Montara to the Coastside Trail, via Vallemar Avenue to the Vallemar Bluff Trail or Julianna Avenue, then proceeding via Weinke Way to California Avenue.

  • Remove the unsafe and poorly located crosswalk at Virginia Avenue and Highway 1

  • Add smart pedestrian crossings on Highway 1 with raised medians and flashing beacons at California Avenue and 2nd St. (exclude Cypress Avenue - explained below).

3. Coastal and Parallel Trails between Moss Beach & Montara 

Another long overdue project is a partial implementation of the Coastal and Parallel Trails between Moss Beach and Montara. This highway section between 16th Street in Moss Beach and 14th Street in Montara is dangerous, particularly for school children to reach Farallone View School and for beach access. Without adequate public transit options, a bi-modal trail could provide relief from auto traffic and also improve safety.

4. Improve Bike Routes
The following options have been discussed for many years. These could be done soon at relatively low cost for much improved safety and access. 

  • Improve bike/ped access on California Avenue west for Coastal Trail connection to Airport Street via the Dardanelle Trail at the Fitzgerald Marine Reserve. Don’t encourage bike/ped use of Cypress Avenue west, as it is too narrow and unsafe and cannot be easily widened due to the creek.

  • Improve bike/ped access on Airport Street.

  • Add marked (Class II) bike lanes on Highway 1 from Devil’s Slide to Half Moon Bay.


5. Improve School Bus Service for Kids
The lack of adequate school bus service adversely affects peak commute traffic. We urge action on this issue with coordination between the schools and the communities involved.

6. Improve Safety at intersection of Highway 1 and Carlos Street 

  • Upgrade Highway 1 / Carlos Street north intersection:
    - No left turn from Carlos Street onto Highway 1
    - Add median on Carlos Street to channel right turn traffic onto Highway 1
    - Add right turn acceleration lane onto Highway 1
    - Clear vegetation on south-facing berm of Highway 1 to improve sight distance.
    - Shorten Highway 1 left turn lane approaches, north to Lighthouse and south to Carlos Street, to provide better separation from the left turn lane for 16th Street and eliminate “suicide arrows.”

7. Address Emergency & Evacuation Concerns Now!

With the growing threat of natural disasters, our coastal community is asking what can be done to manage traffic during emergencies. 

  • How will we ensure the safety of residents and visitors if a disaster should occur when Highway 1 traffic is already gridlocked?

  • How will first responders and their equipment gain access in an emergency traffic situation?

  • What if our only northern evacuation route through the Lantos Tunnel is closed?

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