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Release date: 3/31/11

*** Press Release ***

The San Francisco Municipal Transportation Agency (SFMTA), which oversees all surface transportation in the City, today announced the installation of four green bike boxes on Market Street this week. The eastbound and westbound bike lanes at Market and 9th streets and Market Street and Van Ness Avenue have received green retroreflective thermoplastic bike boxes as part of the SFMTA’s continuing effort to improve bicycling on Market Street and Citywide and as part of a national study to evaluate the effectiveness of colored bike lanes and bike boxes. A fifth box will be added westbound at Market and Gough.

Bike boxes are an innovative treatment designed to improve the visibility and positioning of bicyclists at intersections with traffic signals and to prioritize bicycles as they move through intersections. Bicyclists stopped in a bike box are easily seen by motorists, improving safety at intersections. Bike boxes provide a separated waiting area for bicyclists and can increase pedestrian safety by improving visibility and decreasing both motorist and bicycle encroachment into crosswalks.

“By painting streets, installing bike racks and changing policies, San Francisco is making bicycling safer and more convenient,” said Mayor Edwin Lee. “We can have a significant impact on our environment by increasing bicycling trips and decreasing driving trips. With more and more San Franciscans feeling comfortable while bicycling, we can improve the health and the quality of life for all of our residents.”

“The SFMTA continues to look for a safe and balanced approach to traffic management in San Francisco that will foster sustainable transportation, such as bicycling,” said Nathaniel P. Ford Sr., Executive Director/CEO. “As we implement the Bike Plan, we will identify opportunities, such as the bike boxes, to improve the safety of bicycling in San Francisco.”

Bike boxes consist of an advance line to stop vehicles (including transit buses and taxis) and the box itself with a white bicycle symbol inside it. The boxes serve as bicycle-only waiting areas between crosswalks and automobile traffic. While waiting at a red light, bicyclists can access the bike boxes from the bike lanes when vehicles are present.

The SFMTA has installed bike boxes at two other intersections prior to this week’s expansion to Market Street. In 2005 the Agency installed the first bike box at 14th and Folsom streets, although this bike box does not have a green interior. In December 2009, shortly after the partial lifting of the Superior Court-ordered injunction of the Bike Plan, the SFMTA installed the City’s first green bike box at Scott and Oak streets.

All of the SFMTA bike boxes are outlined with white thermoplastic material instead of paint that is later enhanced with retroreflective materials, just like City crosswalks and other in-street traffic control devices or signs. The Market Street bike boxes are the first to use retroreflective materials, small glass beads and microprismatic reflectors, mixed into the green thermoplastic material filling the bike boxes. These materials have the ability to reflect light and make traffic control devices easier to see at night.

The bike boxes at Market and 9th streets were installed Tuesday and the two at Van Ness Avenue were installed Wednesday. The box at Market and Gough streets will be added next week, weather permitting. The SFMTA plans to collect data to determine the effectiveness of the Market Street bike boxes and may expand this treatment to other intersections that have signals where bicycle lanes exist. These boxes represent the first treatment of this kind in California on a multi-lane transit corridor like Market Street. The SFMTA will pay particular attention to transit and taxi vehicles as part of the analysis.

During the installations, the right-hand traffic lane on Market Street must be closed around the work area at affected intersections. The installations take approximately two to three hours each and are done at off-peak travel times.

The SFMTA is one of several agencies nationwide participating in a Federal Highway Administration National Committee on Uniform Traffic Control Devices study of both colored bike lanes and bike boxes. The Agency’s participation is part of the national effort to add colored bike boxes to the Manual on Uniform Traffic Control Devices—a set of guidelines used by traffic engineers across the country. San Francisco’s participation is funded by Prop K funds, administered by the San Francisco County Transportation Authority.

The attached flyer illustrates how bicyclists and motorists should use the bike boxes.

What Motorists Should Know

When the traffic signal is red, motorists must stop behind the white stop line behind the green bike box. Motorists should not stop on top of the bike box, but rather keep it clear for cyclists to use. Right turns on a red signal will not be allowed at these intersections.

When the light turns green, motorists and cyclists may move through the intersection as usual, with cyclists going first. Motorists turning right on green should signal and watch for cyclists to the right.

What Bicyclists Should Know

When a traffic signal is red, bicyclists must enter the bike box from the approaching bike lane and stop before the crosswalk.

When the light is green, bicyclists should proceed as normal through the intersection. Bicyclists should be aware of right-turning motorists, especially while in the crosswalk and the intersection.

Further Information

For additional information or to provide comments about the bike boxes, please contact the SFMTA at or visit

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