Photo by SFMTA Photography Department
SFMTA has completed the installation of left turn traffic calming at 35 high priority locations on the High Injury Network, using paint, post, and rubber speed bumps to calm left turns at these sites. This project will improve visibility and reduce conflicts for vulnerable road users.
Left turn safety treatments install waist-high vertical delineator posts, small rubber speed bumps, and paint to create enhanced center lane lines and painted safety zones to encourage slower, wider left turns and to increase drivers’ awareness of other road users. According to the SFMTA, in 2019, 40% of traffic deaths in San Francisco were caused by left turn collisions. The SFMTA’s pilot in 2020 for new left turn calming treatments showed a 17% reduction in average left turn speeds and a 71% decrease in high left turn at speeds over 15 mph.
A January press release from the SFMTA announced that San Francisco recorded a significant drop in traffic fatalities in 2025, with 42% fewer traffic deaths in 2025 compared to 2024.
The Transportation Authority supported this Vision Zero Left Turn Traffic Calming project with $100,000 in funding from half-cent sales tax for transportation to support the construction phase of this project.
In September 2025, the San Francisco Board of Supervisors passed the Street Safety Act to improve street safety by coordinating the activities across multiple city departments that are involved in overseeing San Francisco roadways and transportation facilities. Left turn safety treatments will be included as a key tool in SFMTA’s street safety improvement efforts, including Quick Build and Muni Forward projects.