Tuesday, April 26, 2011

Open Letter on Golden Gate Bridge Speed Limit Proposal

To Whom It May Concern:

It came to my attention recently that new proposals were being made for the Golden Gate Bridge’s cycling traffic. As an avid Bridge-crossing cyclist I decided to investigate the issue. I found a copy of the report by Alta Planning + Design and began reading it.

I noticed a number of logic errors within the report which lead to the proposal of a speed limit for bikes. I’ll list them as follows:

1. The Bridge is unsafe. Yes, 2008 and 2009 had the most collisions of any years previous. What isn’t noted is that the number of cyclists, according to the 2008 SF State of Cycling Report, has been increasing at roughly 20% a year (14% from 2006 to 2007, 23% from 2007 to 2008). Using the number of accidents alone to define “safe” or “unsafe” isn’t sound reasoning. To give a measure of safety one has to know how many cyclists are actually crossing the Bridge. If we assume there is more traffic on the Bridge than ever before--which is indicated by the data about increased numbers of cyclists--we would actually conclude the Bridge is getting safer.

2. “Absolute speeds are not as significant a factor in collisions as speeds relative to other path users” (Atla Planning + Design, 9). This statement isn’t supported by the data in the report. The report states there are “five times as many solo bicycle accidents” (ibid., 7). So, if there are five times as many solo bike accidents, but the significant factor is “speeds relative to other path users,” then speeds are not a significant cause of most collisions.

3. “The highest speeds and greatest potential for speed-related collisions comes from road cyclists” (ibid., 12). These two observations are not correlated. Road cyclists, as a matter of practice [and physics] go faster than non-road cyclists. On account of this, they are also more accustomed to these speeds. If anything, they are safer than other cyclists going these speeds. The “greatest potential for speed-related collisions” according to the data cited by Alta Planning + Design, and not its conjecture, is in mixed environments (cyclists and pedestrians) and even in this case it only happened 12% of the time. Thus, just because these cyclists are going faster does not necessarily mean they are a greater risk.

4. “These faster riders generally account for about 10 percent of bicyclists on the Bridge” (ibid., 12). Despite Alta’s assumption these higher speed cyclists have the “greatest potential for speed-related collisions” nowhere in the study is there data to support this assumption. Strictly because speed was a factor in a collision, as reported by the officers on the scene, doesn’t mean it was one of these cyclists. Thus, to state its this sect of cyclists with the highest risk is an opinion, not something that’s based on data.

Speaking of opinions, I have a few on the matter. First, with regard to speed, I would make the same suggestion that BIKESAFE makes and recommend not instating or enforcing a speed limit on shared use paths (ibid., 18). Alta cites this in its report as a source but then ignores the recommendation in its own conclusions. Alta also cites a study which states “speed limits should be used only as a last resort since they require consistent, ongoing enforcement, may not improve real or perceived safety on the trail, and may discourage bicyclists from using trails for commuting.” Lastly, Alta cites the Seawall Trail (ibid., 21) whose General Manager of Engineering Services concluded “the results … are inconclusive, showing little change in speeds.”

Setting a speed limit on the bridge would only serve to punish the commuters or others whose average speed is greater than 10 mph because Alta’s study assumes incorrectly and without factual evidence these are the source of the perceived safety issues. As I pointed out this conclusion is strictly opinion, and not supported by Alta’s own data, or the data of those cited in the study.

From personal experience, many of the unsafe practices I see on the Bridge are due to ignorance. First-time Bridge riders make errors of judgement by attempting to pass without being able to effectively judge how long it will take them to pass. This is the most common and most dangerous maneuver I see on the bridge.

The second most glaring safety concern I see on a regular basis is cyclists on rental bikes stopping in the middle of the path to take pictures.

The third major safety concern I see is cyclists on rental bikes taking up the entire path when riding.

Thus, I agree that a painted line dividing pedestrians and cyclists would be the most effective long term solution to the problem. I also believe that signs instructing bikes to stop against the water side railing and to stay to the right would be effective.

More than either of those, I believe a lot of the problems would be solved by educating cyclists on rented bikes. Since most of these bikes are rented by only a few companies, a simple checklist could be made and given to renters. Something as simple as this:

-Stay to the right on the path.
-Look behind you before changing direction or stopping.
-Use hand signals to indicate changes in direction or slowing speed.
-If you must stop on the bridge, pull over where there is ample room for 2 lanes of bicycles to pass in either direction. Remember to look both ways before merging back into moving traffic.

Finally, I believe my opinion and those of the hoards of avid Bridge cyclists, given the vast amount of experiences traversing the Bridge, should hold more weight than Alta’s conjecture on the issue. Please either commission a study that will support its recommendations with data or save the money and listen to people who ride the Bridge.


*Jarrett Streebin

(Credits to Mel for her edits!)

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