Take a look at the graph. It looks like if we just get more cyclists on the road, that we’ll be safer.
In reality, it just proves you can’t believe everything you see. Recently, I saw a “chainguard” post by John Forester where he claimed that the “safety in numbers” claim for cyclists was a statistical artifact. Frankly, I don’t trust John any more than anybody else with an ax to grind, so I ran the numbers myself. Well, the graph uses Excel’s random number generator for the cycling population, overall population, and accident rate. If I hadn't told you this, would you give credence to the “safety in numbers” hypothesis from the graph? By the way, the LINE in the graph is a mathematical “best fit” of the data. If I did a little fiddling with the numbers, I could easily make the data appear to group even better. Excel's random number generator proves that more cyclists makes all cyclists safer.
Figures may not lie, but liars DO figure. In MY book, the best safety for a cyclist is for that cyclist to ride safer. It’s the ONLY thing he/she can really affect on a daily basis. Besides the basic right to ride safely, the rest is mumbo jumbo propaganda, or political BS, or both…
In reality, it just proves you can’t believe everything you see. Recently, I saw a “chainguard” post by John Forester where he claimed that the “safety in numbers” claim for cyclists was a statistical artifact. Frankly, I don’t trust John any more than anybody else with an ax to grind, so I ran the numbers myself. Well, the graph uses Excel’s random number generator for the cycling population, overall population, and accident rate. If I hadn't told you this, would you give credence to the “safety in numbers” hypothesis from the graph? By the way, the LINE in the graph is a mathematical “best fit” of the data. If I did a little fiddling with the numbers, I could easily make the data appear to group even better. Excel's random number generator proves that more cyclists makes all cyclists safer.
Figures may not lie, but liars DO figure. In MY book, the best safety for a cyclist is for that cyclist to ride safer. It’s the ONLY thing he/she can really affect on a daily basis. Besides the basic right to ride safely, the rest is mumbo jumbo propaganda, or political BS, or both…
6 comments:
Right. Competent cyclists don't need numbers to be safe. That's not speculation.
Jacobsen's theory is used by bikeway advocates to supplant education with infrastructure.
I think of "safety in numbers" as potentially making incompetent cyclists safer by introducing so many incompetent cyclists to the road that motorists become aware of them. IOW, if you're going to have cyclists operating in the door zone, alongside traffic in a dense, complex urban streetscape, you need to have a lot of them!
Chaos = caution.
Like this.So whether or not that's a valid assumption, thinking advocates need to ask themselves: is it good for cycling to increase the numbers of incompetent cyclists? Is it good for the community to do that? What kind of attitude toward cyclists does this type of riding produce in the motoring majority?
Hmm, I hadn't thought of it that way before. We're thinking of cyclists as analogs to zebras. If there's a herd of 100 zebras, the lions will get the slowest one. If the herd is 1000 zebras, they'll still get the slowest one.
The lesson is, given a choice, you're better off to be with a biggger herd. If you're with a given herd, the only useful advice is - "don't be a slow zebra!"
Here is the link to Jacobsen's reply to your post questioning his study: http://bikefriendlyoc.wordpress.com/2009/07/13/ask-the-experts-paul-l-jacobsen-and-dr-lon-d-roberts-phd/
Obfuscation seldom solves problems. For a concise explanation (as concise as an engineer can be) of this issue:
http://www.johnforester.com/Articles/Social/JacobsenReview.htm
Jason, did you ever contact John Schubert to apologize to him for slandering him, and for not posting his civil and professional attempts to discover why you did so? He rather magnanimously gave you his contact info.
Reread the article, PM. Jacobsen is replying to Forester and Steve's articles.
I fail to see the obfuscation in Jacobsen's response to Forester's article:
"First off, this is not the way I did the analysis. The folks saying the data is manipulated need to read the Methods section of my paper. (http://safetyinnumbers.notlong.com)
Secondly, having a variable on both sides changes the exponent by one, and that’s the issue that matters. The other variables change slightly. The key point is that injury rate is non-linear with the amount of walking and biking. Take a look at Table 1 in this recent paper. Lots of researchers have found the injury rate to be non-linear."
Forester simply created a strawman argument.
Post a Comment