06 June 2013

Passing: How Close?

Here's something I can't believe I missed.

Six years ago, Scientific American's blog reported on a study about helmet-wearing.  According to British researcher and cyclist Ian Walker, motorists give a wider berth to helmetless (Is that a real word?) cyclists than to those of us who don hard shells.  

How did he come to this conclusion?  He attached ultrasonic sensors to his bike and allowed 2300 motorists to overtake him as he pedaled in and around Bath.  His data indicated that drivers passed 3.35 inches closer to him when he wore his helmet than they did when he was bareheaded.

He also conducted another experiment: On some of his rides, he wore a wig of long brown locks to make him look like a woman from behind.   When motorists thought Ian was Lana, they gave him an average of 2.2 more inches to ride, he said.

His findings are interesting, to say the least.  Now, I have no experience in conducting experiments like his.  But I have to wonder just how good his data actually is.  After all, he was the only test subject. So, I have to wonder whether other factors might have influenced the way motorists passed him on the road.

From Bike New York

 From all of my experience of cycling, I honestly don't know whether  wearing a helmet influences the amount of room motorists give me.   Then again, about the only times I notice how much of a berth I'm granted are when the cars are close enough to scrape the crocheted back off my glove.

As for the male-female thing: Most mototrists may well be giving me more room than I got when I was Nick. But, every once in a while, some male driver pulls up close to me and whistles, makes a comment like "Nice legs!" or finds some other way to annoy me.

In spite of Walker's findings, or any others, I'll most likely continue to wear my helmet.  While it may cause drivers to ride closer to me, I want to have it on if I'm in an accident. Once, when I flipped over (through no fault of any motorist), my helmet broke in two but I emerged with nothing more than a few scratches on my left arm and leg.  Another time, a tiny Vietnamese truck driver flung his door into me, causing me to do an unintentional cartwheel on my head.  I came out of that with a sprained wrist.



  1. Have you looked at Dr Walker's blog? He did a follow-up on that research at http://bamboobadger.blogspot.com/2009/03/bicycle-overtaking-and-rebuttals.html

    He makes the interesting point that passing distance is also a function of road specifics which certainly tallies with my own experience.

  2. Steve--Thanks for pointing me to Dr. Walker's follow-up. I agree with you that the distance motorists give (or don't) give us has as much to do with road conditions as anything else.