[Stoniaanapy]

From a security

newsletter I get.

We've had previous discussion in RISKS of the unexpected side-effects that can result

when human beings respond to safety measures by changing their behavior, taking on risks that previously were too

great to feel acceptable.

http://www.eurekalert.org/pub_releas...-wah091106.php is a news

release about some research in this area. Dr. Ian Walker spend a great deal of time bicycling around the UK on a

bicycle with equipment that measured how close drivers of different kinds of vehicles came to him when

passing.
Half the time, he wore a helmet; half the time, he didn't. Result: Drivers
approached closer (and

average of 8.5 cm) when he was wearing a helmet.

Walker's hypothesis is that drivers see bicyclists wearing

helmets as more
experienced and competent, hence not in need of consideration.

In other interesting results,

when Walker wore a wig so that he looked like a woman, he was given significantly more room. He also confirmed a

feeling all bicyclist have: Yes, indeed, trucks and buses do approach bicycles more closely (average of 19 cm for

trucks and 23 cm for buses) than cars do.

As Walker points out, helmets definitely do protect a rider in

low-speed
falls. How much they help in collisions with vehicles is harder to say -
and if wearing a helmet makes

a collision more likely, the net effect is
difficult to predict. (Walker was hit twice, once by a bus and once by

a
truck, during his experiments. He was wearing a helmet both times.)