Automatic Traffic Signals and Their Operation
| Date | 01 October 1939 |
| DOI | 10.1177/0032258X3901200414 |
| Author | G. W. Barlow |
| Published date | 01 October 1939 |
| Subject Matter | Article |
Automatic Traffic Signals and
their Operation
By
POLICE
CONSTABLE G. W. BARLOW
Traffic
Department,
New
Scotland
Yard
GENERALLY
speaking, manual control of traffic is not a
pleasant task, and most of us have experienced point duty
under extremes of temperature. We have complained about
the heat and the cold,
but
if the installation of Automatic
Traffic Signals has meant the abolition of a traffic point, have
we complained
then?
Idon't think so.
This traffic signal business is one of complexity, and I
think it is realised that present-day methods of electrical
control mean more than a few relay-sets to give us a sequence
of lights, with the colours and code of which we are so familiar.
We know that signals are either fixed cycle or vehicle-
actuated,
but
how many kinds there are is another matter.
This article, then, is a survey of traffic signal types, and no
attempt will be made to delve into their mechanical or electrical
intricacies.
The
following tables are, up to a point, self-
explanatory.
I
FIXED
TIME
CYCLE
SIGNALS
II
Purely Electrical
I
I
Isolated
Control
I
Mechanical
II
Linked
or
Flexible
Progressive
482
I
Isolated
Control
I
Linked
or
Flexible
Progressive
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