Police Warning Lamps
| Date | 01 May 1961 |
| Author | V. J. Jehu |
| Published date | 01 May 1961 |
| DOI | 10.1177/0032258X6103400313 |
| Subject Matter | Article |
that it flashed
powered by a
May-June 1961
V. J.
JEHU,
M.Sc., A.Inst.P.
Road Research Laboratory, Department
of
Scientific and Industrial
Research
The work described below was carried out in the programme
of
the
Road Research Board
of
"
D.S.l.R.".
The article is published by
permission
of
the Director
of
Road Research.
Poliee
Warning
Lamps
The
Problem
THE UNEXPECTED OBSTRUCTION of the road caused by vehicles involved
in an accident is itself a hazard that may lead to further accidents,
especially at night on unlighted roads. Various types of portable
reflectorized warning signs have been used by police forces when
dealing with an accident, and their standardization is probably
desirable. The reflectorized message, however, provides an early
warning, only when it is seen in headlight beams, and the laboratory
was asked to investigate the possibilities of a portable lamp to alert
drivers before they reached the reflectorized sign. This article con-
tains recommendations for such a lamp, based on experience gained
with experimental lamps.
Basic
requirement
Preliminary discussions with police representatives established
that what was required was a portable self-contained lamp exhibiting
a flashing red light powerful enough to be noticed by the fastest
moving traffic.
It
was considered essential for the lamp to flash in
order to differentiate it from rear lights. Another requirement was
that the lamp should not be costly.
Experimental Lamp
Of the lamps available commercially, that which most nearly met
the requirement emitted a weak flashing red light in all directions and
a non-flashing concentrated beam of white light that could be aimed.
Examples of this lamp were modified by transferring the flasher unit
to control the concentrated beam of light and by adding a signal red
lens to the lamp. The regularity of the rate of flashing was improved
by substituting ahigh-grade American flasher unit in place of the
original one. An added advantage of this substitution was a reduc-
tion in the warming-up period. The rotary switch was modified to
improve its reliability.
Laboratory tests with a modified lamp showed
reliably for at least 20 hours continuously when
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