Officials unveil Outer Sunset traffic calming plan to stem flow from closed Great Highway

City officials this week announced a new traffic plan to curb Outer Sunset traffic safety concerns that resulted when a portion of the Great Highway was closed to vehicles.

Since April, the Upper Great Highway has been closed to vehicle traffic between Lincoln Way and Sloat Boulevard as a way to provide more open space for residents to bike and walk. Nearly 4,000 people on weekdays and 12,000 on weekends take advantage of the car-free area, transit officials said.

District 4 Supervisor Gordon Mar said the closure has provided a number of benefits for the Outer Sunset, but added that the closure inadvertently diverted vehicles to the avenues and the Lower Great Highway, which were not equipped to handle the traffic volume.

Mar and the San Francisco Municipal Agency said Wednesday that they have negotiated a deal to install traffic calming traffic measures around the affected roadways.

The new safety measures include:

• 24 new speed cushions
• One speed table
• 12 new stop signs spread along Lower Great Highway, La Playa Street, Irving Street, 48th Avenue, 47th Avenue and 46th Avenue
• Six new changeable message signs to divert traffic away from residential streets onto corridors like Sunset Boulevard

Mar, who originally supported the Great Highway closure, said in a statement:

“We can’t sacrifice safety for recreation, and I believe with this plan we can have both. We can only continue to enjoy this incredible new open space if we can make it safe and address these impacts.”

Mar and transit officials held a virtual public meeting in November to discuss the future of the Great Highway. In that meeting, San Francisco County Transportation Authority Senior Transportation Planner Camille Guiriba said the agency had counted vehicles over a three days in October, recording about 5,000 vehicles per day.

While there were no vehicle counts gathered immediately prior to the pandemic, Guiriba said in that meeting that the agency estimated the Upper Great Highway was used for nearly 19,000 daily vehicle trips, a higher volume than what is seen on a typical residential street.

Transit officials expect the measure will move quickly, with the changeable message signs and stop signs installed by mid-March. Construction of the speed cushions and speed table will also begin in March and continue through April.

In the meantime, the SFMTA said San Francisco police will increase weekend enforcement and deploy additional parking control officers to divert vehicles.

SFMTA Director of Transportation Jeffrey Tumlin said in a statement:

“We’re eager to support Supervisor Mar and District 4 by installing additional traffic management tools to increase safety for all in the area, while also exploring the Great Highway’s long-term potential.”

The plan is being funded through the transit agency, county transportation authority and Recreation and Parks Department. The SFCTA will vote on the proposal Tuesday and traffic calming strategies will be presented at upcoming SFMTA public hearings.

According to SFCTA data, construction cost for the proposed traffic calming measures is estimated at $568,766.

Jerold Chinn

Jerold serves as a reporter and San Francisco Bureau Chief for SFBay covering transportation and occasionally City Hall and the Mayor's Office in San Francisco. His work on transportation has been recognized by the San Francisco Press Club. Born and raised in San Francisco, he graduated from San Francisco State University with a degree in journalism. Jerold previously wrote for the San Francisco Public Press, a nonprofit, noncommercial news organization. When not reporting, you can find Jerold taking Muni to check out new places to eat in the city.