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Newspaper Page Text
COPPER INVENTS TRAFFIC SIGNAL
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Traffic Semaphore Invented By Oakland Policeman.
Oakland, Cal., April 15. A street
semaphore that is all hut human has
been invented by J. C. Wallman of
the Oakland, Cal., police "department.
Chief of Police Walter Petersen calls
it the "last word in automatic devices
for handling street traffic."
Wallman's device is electrical.
New York uses semaphores operated
by hand levers by the traffic police
men, but there are disadvantages to
this. The policeman cannot keep his
eyes constantly on the traffic, as he
must pay some attention to hia levers.
The new electric semaphores are
being installed at 12th and Broadway,
Oakland's busiest corner, and will be
given a thorough tryont.
A semaphore arm at each of four
corners, controls traffic in all direc
tions and dn both sides of the street.
The arms are controlled by four elec
tric buttons, held by the traffic police
man in the center of the street. The
current used is from the regular
street lighting service.
t Each semajhoie arm signals thiee
ways visually, besides sounding an
alarm. When traffic is to be held up,
the arm is horizontal and a sign reads
"Stop," a red light being used for
night signals. When the traffic is al
lowed to. go forward on that side of
the street, the arm drops, and a new
sign is shown, or, at night, a green
light All this is done automatically
by a simple system of magnets and i3
controlled by pressing "a bfitton.
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