In 2014, San Francisco took a bold step by making a Vision Zero pledge aimed at eliminating traffic fatalities within a decade. However, the city has not only failed to meet this ambitious goal, but it has now recorded its highest number of traffic-related deaths in a single year, with 42 fatalities in 2023.
While these deaths often make headlines, non-fatal collisions resulting in serious injuries occur almost daily, leading to life-altering consequences for many individuals. The hopes tied to the Vision Zero initiative did not lead to a significant decrease in annual injury totals, either.
With the pledge now expired, San Francisco finds itself in search of new strategies to unlock the secret to not only slowing down drivers but also ensuring the city’s streets are safer for all.
On Tuesday, Supervisor Myrna Melgar will introduce new legislation aimed at fostering collaboration among various city agencies. She emphasizes the need for a concerted effort to achieve safe, comfortable, calm, and vibrant streets, according to her aide, Emma Hare.
The relationship between speed and fatality rates is well-established. A widely cited study by the Automobile Association of America reveals that pedestrians struck by vehicles traveling at 40 miles per hour or faster have a three in four chance of suffering severe injury or dying.
Conversely, if a vehicle is traveling at 25 miles per hour or slower, the odds of severe injury or death drop to one in four. Increased speed not only reduces a driver’s field of vision, but it also lengthens the distance required to stop, creating a perilous situation on busy streets.
A diagnostic report from the San Francisco Municipal Transportation Agency (SFMTA) states that from 2020 to 2024, speeding was the most prevalent traffic violation linked to injury and fatal crashes in the city.
To combat this pressing issue, San Francisco has implemented various measures such as speed bumps, new automated speed cameras, daylighting intersections, and traditional police enforcement.
However, each of these methods faces significant challenges. The rollout of speed cameras is underway, but only 33 cameras will be installed during a five-year pilot program. Meanwhile, the speed bump program has been halted due to a backlog of applications at SFMTA, which was recently allocated an additional $7 million to expedite approved projects by 2023.
Police enforcement presents another layer of complexity. A civil grand jury report cited the chronic lack of enforcement by the San Francisco Police Department (SFPD) as a critical factor in the failure of the Vision Zero initiative. An investigation by San Francisco Standard has, however, raised questions about these conclusions.
San Francisco can also lower speed limits, a low-tech solution established by a 2021 California law that allows cities to set their own speed limits on specific streets. Following this law, SF promptly lowered the speed limit to 20 miles per hour in the Tenderloin district and has since applied similar reductions on over 80 other street segments.
While SFMTA has reviewed previously implemented speed limit reductions for their impact on traffic speeds, they have yet to evaluate their effect on injury collisions.
To address this gap, The Frisc analyzed 12 major street segments notorious for dangerous conditions where speed limits were lowered to 20 mph in recent years, intending to assess the effectiveness of these measures.
The analysis indicates that eight out of the twelve segments experienced a dramatic reduction in injury collisions, with improvements up to 50 percent. Notably, street segments in the Tenderloin showed some of the best outcomes.
Golden Gate Avenue, stretching from Market Street to Van Ness Avenue, exhibited the most remarkable change, with a 56 percent decline in injury collisions. Two additional Tenderloin streets, Taylor and Turk, showed improvements of 43 percent and 29 percent, respectively. These streets, originally designed as fast one-way thoroughfares after World War II, have now become focal points for safety improvements.
However, not all changes have yielded positive results. Eddy Street saw an 81 percent spike in injury collisions after its speed limit was reduced. SFMTA traffic engineer Ricardo Olea emphasized that while he verified the increase, he was uncertain about its cause and flagged it for additional study.
Different street configurations played a role; Eddy is a two-way street, and modifications are currently underway to introduce a bulb-out at the intersection with Larkin Street to enhance pedestrian safety.
An examination of Mission Street, known as San Francisco’s longest corridor, revealed mixed results following speed limit reductions on various segments.
In downtown segments, for example, injury collisions dropped by 34 percent between The Embarcadero and Beale Street, while a nearby section between First and Third Streets saw a 40 percent increase in crashes.
Outlying neighborhoods along Mission Street also displayed a split in data; injuries decreased by 14 percent between Silver Avenue and Foote Street in the Excelsior, while in the Mission District between 14th and Cortland Streets, crashes rose by 8 percent.
Marcel Moran, an assistant professor at San Jose State University and one of the experts who evaluated The Frisc’s findings, noted that measuring the effectiveness of traffic calming measures is inherently complex. The implementation of lower speed limits usually happens alongside other safety improvements, making definitive conclusions challenging.
In the Mission District stretch, factors such as the addition of a red transit-only lane effectively reduced the number of vehicle lanes, which could have impacted safety despite the 20 mph speed limit.
The investigation also considered main corridors in neighborhoods such as Columbus Avenue in North Beach, Third Street in Bayview, Upper Market Street, and 16th Street in the Mission. Results indicated that only Third Street experienced an increase in injury collisions.
Overall data suggest that the reduction of speed limits is contributing to significant improvements in traffic safety when paired with additional strategies like no-turn-on-red restrictions, according to Moran.
However, Olea cautions against drawing conclusions from the limited sample size and advocates for a more comprehensive analysis, which has not been conducted yet for San Francisco. Other cities, however, present compelling case studies.
In 2016, Seattle enacted a decision to lower default speed limits to 20 mph on residential streets, alongside 25 mph on arterial streets. A follow-up analysis conducted by the city’s transportation officials in 2020 revealed a 22 percent drop in fatal crashes and an 18 percent decline in injury crashes.
Additionally, instances of egregious speeding were cut by more than half. City engineers achieved these results without making significant modifications to the streets, relying instead on strategically placed signage to remind drivers of the new limits.
Studies have indicated that frequent reminders about speed limits significantly enhance safety outcomes, emphasizing the advantages that prompt action can have on driver behavior.
Conversely, a less comprehensive study was conducted in St. Louis Park, a suburb of Minneapolis. Researchers assessed the impact of a speed limit reduction from 30 mph to 20 mph on 28 two-way streets. The findings showed only modest speed decreases of 1 to 2 miles per hour on average, aligning with similar results observed in cities like Bristol and Edmonton, where lower limits were enacted without aggressive enforcement or physical changes to the streets.
As new data emerges, New York City is in the process of implementing lower speed limits at 250 locations, spurred by a state law passed last year after several previous attempts fell short.
San Francisco’s sole study on the impact of speed limit adjustments comes from SFMTA, which predominantly focused on vehicle speeds without providing insights into the collision effects. The agency’s assessment covered nine activity districts, including Haight Street and San Bruno Avenue, where speed limits were reduced from 25 mph to 20 mph in 2022.
While SFMTA reported a lack of change in daily vehicle speeds, implying a decrease in compliance with the new limits, the findings did not directly delve into accident rates.
Existing state laws constrain the city’s ability to further reduce speed limits but allow for reductions in commercial districts, high-injury streets, and areas with significant vulnerable populations, including seniors and children.
Olea notes that SFMTA selects segments for speed limit reductions based on geographic and community needs.
Advocacy groups, such as Walk SF, are demanding a citywide 20 mph limit to create a greater sense of consistency. Their communications director, Marta Lindsey, argues that a uniform speed limit would enhance safety across the board.
Melgar’s proposed San Francisco Street Safety Act recognizes the need for multi-faceted approaches in achieving safer streets. The bill outlines specific tasks for multiple city agencies, including deadlines for implementing work.
For example, the legislation calls upon SFMTA to deliver a redesigned plan for high-injury streets by 2026, incorporating traffic-calming measures and physical barriers to separate pedestrians from vehicles.
Currently, advocates are pushing to expedite these changes, as critics assert that long review processes, particularly by the fire department, impede progress.
Melgar’s bill imposes a 90-day maximum limit for SFFD reviews of specific projects to keep ground on the agenda.
Moreover, the Department of Public Health is tasked with developing a new street risk map that incorporates not just serious collisions but also near-misses. Emma Hare notes that this effort aims to reduce conflict between various road users including pedestrians, cyclists, vehicles, and public transit.
The administration led by Lurie is promoting a vision of a more effective government to tackle small business and homelessness issues. However, the city’s history with collaborative street projects has been inconsistent.
In order to achieve the Vision Zero goal of safer streets, it will be crucial for San Francisco to determine effective strategies, break down bureaucratic barriers, and prioritize actionable solutions.
image source from：thefrisc
