[DVBC] neodymium magnet testing results

[Douglas Bower]

For those interested in knowing weather a neodymium magnet attached to
the bottom of your $200.00 light weight bicycling shoe can trigger a
traffic light read on.
 
Drew Knox was able to provide 2 very powerful neodymium magnets for
testing.  The intersection of Broad St and Garfield Rd in Lansdale has a
traffic light that is configured to provide north, south bound traffic a
green light until an east, west bound automobile approaches.  There
appears to be no other way of triggering the light to change.  Some
traffic lights are configured to change by approaching cars or by a
timer.  This intersections traffic light appears to have no timer
configured, as I have sat at that light for a very long time without the
light changing. 
 
The sensing device is imbedded into the pavement about 30 feet before
the light.  I taped the biggest magnet to a piece of string and waved it
over the sensing wire.  I waved it around the corners of the wire and
along the entire length of the wire.  I was at that intersection for
over 20 min. no automobiles approached from either side of the
intersection and the light never changed.  I tied a 12 inch adjustable
wrench to the string and waved it over the wire with the same results.
After returning to my car I drove over the sensor wire and the light
tripped almost instantly.  So my recommendation to all DVBC members is
do not waste time attaching a magnet to your shoes..
 
I am interested in knowing what the Pennsylvania law is regarding
traffic lights that will not change.  I was told by a respectable DVBC
member that there is some provision in the law that allows you to
proceed through a light if it is not functioning.  The problem with
these types of lights is they are not not functioning, they work exactly
as they were designed.
 
Doug  
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