SFMTA Adds Two Left Turn Bike Boxes in SoMa

The SFMTA installed left turn bike boxes at two SoMa intersections this week. This type of bike infrastructure, new to SF, debuted at Market and Polk Streets last month with the new contra-flow Polk bike lane.

The new green-backed bike boxes were placed at two intersections where bike commuters often make "two-stage" left turns between bike lanes: Eighth Street for turns on to Folsom Street, and Howard Street for turns on to 11th Street. They provide guidance and visibility, to show where people on bikes should stop and wait for traffic signals to change.

"Making a left turn across several lanes of traffic isn’t always the easiest thing to do, especially for people who are less confident on their bike," said SFMTA Livable Streets spokesperson Ben Jose. The turn boxes should make two-stage turns "more easy, safe and comfortable for people of all ages and abilities."

The SFMTA said the boxes were funded by a grant from People for Bikes, a national bike advocacy organization. Left-turn bike boxes are featured in the SFMTA's "Innovative Bicycle Treatment Toolbox," drafted two years ago, and largely based on the National Association of City and Transportation Officials' Urban Bikeway Design Guide.

Jose said the SFMTA "will be evaluating the measures on the ground, and observations will guide future implementation."