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Date: Fri, 20 Sep 85 11:44:01 EDT
From: heddaya@harvard.ARPA (A. Heddaya - Solom)
To: Harry.Bovik@cmu-cs-a.ARPA
Subject: Bike Safety Tips in City Traffic


Have a thick-tire bike!
Have a light and airy helmet and always wear it!

Twice this past summer I fell off my bicycle, although I have cycled
since I was a little kid.  Here's what happened, and the lessons I
learnt.

What happened:
--------------
    The first time I fell off my 10-speed Raleigh was on the Charles
    river asphalt bicycle track in Boston.  As I went through a bend
    in the track, the front wheel hit a patch of dust, which caused it
    to slide.  The whole bicycle as well as myself slid over the
    asphalt and my left arm was badly scraped.  Dust has a lower
    friction coefficient than asphalt.

    The second time was on a busy street in Boston with street car
    tracks.  Again it was the front wheel of my 10-speeder.  This time
    it fell into the groove in the street car track, which simply
    locked it.  Despite my low speed, I was catapulted in the air,
    landing on my right shoulder and banging my right cheek on the
    ground.  My shoulder--luckily-- did not break, but it was badly
    sprained.

Moral:
------
    HAVE THICK WHEELS.  In both cases, a thick tire would have saved
    me: it has high friction so it won't slide as easily, and it is
    bigger than grooves in street car tracks (and rain water sinks).
    Also, a small number of gear ratios (less than 5) is the most you
    need in city traffic (even in Pittburgh hills), since the 5 higher
    ratios only encourage higher speeds.  Finally, thick-wheel bikes
    tend to be more manoeuverable, which is pretty critical in city
    traffic.

    WEAR YOUR HELMET.  And get one that you can use in summer.  Both
    doctors in the two cases told me I was pretty lucky I didn't hurt
    my head.  I didn't have my helmet on because it was too hot.  A
    lower protection helmet which is light and airy is better than a
    full protection helmet that you can't wear because it is too hot.

Enjoy safe cycling.  It's fun.  It's exercise.  It's flexible
trasportation.

\Solom
			Abdelsalam Heddaya
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