San Francisco transportation officials have released the most comprehensive analysis yet of traffic changes following the creation of Sunset Dunes Park, revealing that the controversial road closure has caused manageable but noticeable impacts on west side commuting patterns four months after the oceanfront park opened.
The Spring 2025 Outer Sunset Traffic Data Report, released Friday by the San Francisco Municipal Transportation Agency (SFMTA), found that traffic circulation changes were "largely aligned with transportation model predictions" following the permanent closure of the Upper Great Highway between Lincoln Way and Sloat Boulevard in March. The closure created California's largest pedestrianization project, transforming the two-mile coastal stretch into a 50-acre park that officially opened as Sunset Dunes on April 12.
Traffic Impacts Align with Predictions
According to The San Francisco Standard, early data in April showed significant traffic increases on alternative routes, with the Lower Great Highway seeing more than doubled traffic during peak commute times. The latest SFMTA report confirms these initial findings while providing a more nuanced picture of the changes.
The agency found that Sunset Boulevard experienced a 28% increase in traffic but remains at only 90% of pre-pandemic levels. The San Francisco Examiner reported that Chain of Lakes Drive saw a 21% increase in traffic, within SFMTA's predicted range of 20% to 25%. Lower Great Highway gained approximately 700 additional vehicles per weekday, representing about 5% of trips formerly made on the Upper Great Highway.
Muni Service Sees Mixed Results
Public transit impacts varied by route, with the 28 19th Avenue line experiencing the most significant delays. According to the SFMTA data, southbound 28 service saw an average increase of 104 seconds over its 4.6-mile route, rising to 110 seconds during evening peak hours. The 29 Sunset route had more modest impacts, with an average daily increase of 26 to 33 seconds, though evening southbound trips increased by 71 seconds while morning southbound trips actually improved by 44 seconds.
The 18 46th Avenue route, running directly adjacent to the former highway, showed no significant changes in travel times, according to the report.
Political Controversy Continues
The park's creation has sparked intense political debate, culminating in a recall campaign against District 4 Supervisor Joel Engardio, who championed the closure. Ballotpedia reports that recall organizers submitted 10,523 valid signatures in May, triggering a special election scheduled for September 16, 2025.
Engardio's support for Proposition K, which passed with 54% citywide support in November 2024, has made him a target for west side residents who opposed the closure. The Standard noted that while the measure passed citywide, 64% of District 4 voters opposed it, leading some residents to claim Engardio "betrayed" them.
Park Success Amid Opposition
Despite the political controversy, Sunset Dunes has proven popular with visitors. The Standard reported that the park welcomed 13,000 visitors on opening day and became the city's third most-visited park. Interestingly, polling found that 61% of early visitors came from west side neighborhoods that voted against Proposition K, including many who opposed the closure but now enjoy using the space.
The park features public art installations, including the popular "Octavius Octopus" sculpture at Sloat Boulevard, skateboarding areas, and restored sand dunes. Bloomberg described the transformation as bringing "big crowds — and plenty of controversy" to the oceanfront space.
Infrastructure Improvements
To support the closure, the city and Caltrans completed several infrastructure projects, including new traffic signals at key intersections. The SFMTA report details improvements at Sloat and Skyline boulevards, 41st Avenue and Lincoln Way, and signal modifications at Great Highway and Lincoln Way. Public Works also completed a full repaving of Sunset Boulevard between Martin Luther King Drive and Lake Merced Boulevard.
Future Changes Expected
Additional changes are planned as the Ocean Beach Climate Change Adaptation Project advances. The SFMTA report notes that the northbound Great Highway Extension from Skyline to Sloat Boulevard will remain open until early 2027, when it too will close permanently as part of coastal protection efforts against sea level rise.
The data comes at a critical time for both supporters and opponents of the park. Streetsblog San Francisco noted that Sunset Dunes advocates like Lucas Lux, president of Friends of Sunset Dunes, argue that the park's success demonstrates the value of "political courage and vision" in creating public space.
The release of comprehensive traffic data provides the most detailed picture yet of how the Great Highway closure has affected San Francisco's transportation network. The San Francisco Chronicle previously analyzed traffic data showing that while some routes experienced delays, the impacts were more modest than critics predicted.
