Golden Gate Bridge bike speed limit

The Golden Gate Bridge District Operating Committee will meet Thursday morning to consider a proposed 5 MPH and 10 MPH bicycle speed limit on the Golden Gate Bridge sidepaths.

Golden Gate Bridge bicycle

Letters to the GGB Board

I’ve seen a couple of letters that San Francisco cyclists have written to the GGB Board on this 10 MPH speed limit issue.

  • djonnel writes “the statistics do not justify such an action,” pointing out that Alta’s statistics shows “one collision per 81 thousand miles ridden. This is likely lower than typical urban motor vehicle collision rates.”

    Dan also attacks Alta’s ludicrous logic that “Bicyclists accustomed to riding unimpeded at a relatively quick speed over the Bridge on weekend rides may have difficulty adjusting to sharing the path with slower moving pedestrians.” “With this logic,” writes Dan, drivers on I-280 should be limited to 25 MPH because of nearby residential streets with that speed limit.

  • Mike Fogel writes as an A-to-B cyclist, telling the Bridge District that 10 MPH is too slow for a utilitarian trip across the Golden Gate Channel. He notes the bi-modal distribution of speeds — one peak represents slow tourists taking their time, and another peak for those traveling between Marin and San Francisco.
  • Local cyclist Barry hasn’t posted his letter online but to the SFBIKE email list, but reminds the Bridge District that California speed limits must be set using the 85th percentile rule — that is, at a speed that 85% of drivers go on a given road. This is one standard deviation above the mean in a normal distribution and is the gold standard for speed limits in California. Alta’s study makes no mention at all of this 85th percentile, but instead recommends a bicycle speed limit below the current mean on the bridge!

    The 85th percentile rule applied to the GGB results in a speed limit of 17 to 23 MPH for cyclists. With the usual 10 MPH wiggle room means the CHP will only pull cyclists over who ride faster than about 30 MPH. Barry then suggests that the Bridge District just enforce current law, which says cyclists must use “due caution and circumspection.”

Alta Planning & Design submitted their “Bicycle Safety Study for the Golden Bridge.” While they concede that safety is not a serious issue on the Golden Gate Bridge (GGB) sidewalks, they were paid to Do Something, so Alta Planning recommends a 10 MPH bicycle speed limit at all times on the west and east sidewalks, with a 5 MPH speed limit around the towers, where space and sightlines are constrained.

GGB Staff forwarded this report to the Building and Operating Committee with their endorsement. If this committee approves the proposal, they will forward it to the full board for their approval on May 13, 2011.

Besides the 5 MPH and 10 MPH speed limits, Alta recommends a ban on tallbikes and unicycles because they might tip over the bridge safety railings and fall into the Golden Gate, like certain high school students have been known to do lately. Alta has a good idea by recommending signs telling pedestrians to stay to the right side of the east sidewalk when bicycles are passing by.

Contact the Golden Gate Bridge District

As far as I can tell, the GGB District neither sought or received input from those who would be impacted by this proposed speed limit, depending only on information from Alta Planning’s study. The GGB District does not have a bicycle or pedestrian advisory committee.

This committee meets this Thursday morning at 10 AM in the Board Room, Administration Building, Golden Gate Bridge Toll Plaza, San Francisco, CA. The GGB Administration Building is the beige block immediately adjacent to the southbound toll plaza. If you show up to this meeting, you’ll have 3 minutes to speak during the public comment period.

To provide your feedback to the Golden Gate Bridge District on this issue, you can send email through the Board Secretary. You can also write the Board with snail mail at

    President of the Board
    Golden Gate Bridge, Highway and Transportation District
    P.O. Box 9000, Presidio Station
    San Francisco, CA 94129-0601

Finally, you can fax a letter to (415) 923-2013.

My opinion

Alta reports that they measured average cycling speeds of 7 – 10 MPH on the upslope portion of the bridge, 10-13 MPH on the flat part, and 13 – 17 MPH on the downslope portion (with no explanation of why their “averages” are given as a range of speeds). Alta says increased risk of collisions occurs when cyclists try to pass other bridge users too fast, which makes sense, but cyclists traveling at these average speeds are likely not passing each other at dangerously fast. Alta even acknowledges that the sidewalks are reasonably safe even now, and asking the CHP to expend resources on bicycle speed limits seems like a waste of scarce state resources to me.

I get annoyed at the speed demons when I’m slowly riding across the GGB with my family, but 10 MPH is unreasonably slow. GGB District’s failed to even solicit user input on a change that will impact every regular bridge user.

Details on the Committee resolution, staff report, and Alta Planning study on the bicycle speed limit can be seen here. H/T to Murph.


  1. The meeting is open to the public, and the bike stuff is first on the agenda –

    THURSDAY, APRIL 21, 2011, at 10:00 a.m.
    Board Room, Administration Building, Golden Gate Bridge Toll Plaza,
    San Francisco, CA

    And the meeting is governed by the rules of the GGB board, which state
    somewhat plainly that the public is allowed to participate in the
    discussion of each agenda item to a limited extent. It does seem to
    indicate that if a lot of people showed up, and wanted to comment on
    this proposal, the board is obligated to listen to all of them,
    potentially delaying action on other larger issues on the agenda (read

    RULE III. D. …”Public comment will be received on items calendared
    on the Agenda as each item
    is discussed.”

    This means that you can comment publicly on the specific agenda item
    when it is brought up.

    RULE XV. E. “At the public hearing, the District shall afford any
    interested person or duly authorized
    representative, or both, the opportunity to present statements or
    arguments. Limitations may be
    established on the length of oral presentations in order to afford all
    members of the public a reasonable
    opportunity to speak.”

    But they may limit you to a few minutes.

  2. “If you show up to this meeting, you’ll have 3 minutes to speak during the public comment period.”

    This is not completely correct. According to the bylaws (see my previous comment), you can provide comments while the issue itself is being discussed. The public comment period is for issues that are not on the agenda.

  3. After reading the study, they didn’t seem to look into what might be the potential root cause of the accidents beyond “speed” being a factor. If my weekend rides over the bridge are any indication, “swerving”, “blocking half of the path around the towers for a family photo op”, or “filming entire trek across the bridge while riding one-handed”, may also be a factor.

    This seems completely reactionary and is disconcerting that they apparently didn’t seek any input before scheduling this meeting at 10AM on a Thursday (so that anyone who wants to comment has to leave work, nice timing!).

    Supposedly this is all being suggested because the west sidewalk will be closed for construction, meaning two directions of cyclists and pedestrians will all be crammed into a narrow walkway. Would have been better to close off one lane of traffic and create a protected lane for cyclists, but I doubt that would ever happen.

  4. Personally I feel like there are cyclists who ride too fast on the GGB, but 10 MPH is too much. Construction concerns are fine, but, again, a blanket speed limit for all times and all users?

  5. The speed limit is only one of the recommendations in the report. Another recommendation is having pedestrians walk on the outside half of the lanes, with bicyclists only on the inside. I think this is especially dangerous since bicycle traffic is 2-way and the recommendation will cause more head-on collisions. These paths need to use standard road rules (everyone stay to the right). And encourage everyone (bicycles and pedestrians) to travel single file to minimize conflict.

  6. California law already addresses tall bikes:

    21201. (c) No person shall operate upon a highway a bicycle that is of a
    size that prevents the operator from safely stopping the bicycle,
    supporting it in an upright position with at least one foot on the
    ground, and restarting it in a safe manner.

  7. Instead of the summer-long daily clusterfuck of 10000 pedestrians and 6000 bicyclists traveling in both directions on a single narrow sidewalk, why don’t they close one of the *six* auto lanes to cars for the duration of the project? That would provide plenty of room for a bidirectional bike lane.

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