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ilp archive : journals
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public lighting no. 39 vol. 10: conference issue part 2
October-December 1945
- Editorial p105
- Accidents and Street Lighting / Make Side Roads Safe p105
- Every Public Lighting Engineer should make himself acquainted with the statistics of road accidents,
which are issued regularly by the Ministry of War Transport. These serve as a pointer to the success, or
otherwise, of methods adopted to overcome street accidents.
- In recent weeks a private and quite unofficial survey has been taking place in certain districts within
the London County with a view to suggesting improvements in side road lighting. The Report, unfortunately,
contains some disappointing information. Too many side roads appear to be black holes with an odd lamp
placed here and there.
- Main road lighting is indeed worthy of highest praise, and a credit to both the Lighting Engineer and the
lamp and lantern manufacturers.
- In the survey, it was felt that gas lighting in many cases was a distinct improvement over electric lighting.
The low mounted gas lamps, with the pleasing and soft-coloured light, appeared to give out a wider spread
of even light, in constrast to the sharp light from the filament electric lamp. In the latter case
the brightness of the source of light "killed" the spread of light on the road - and in cases where a
particular type of reflector was installed, shafts of glare appear which is most discomforting for
the road user.
- Side road lighting needs a good overhaul - it's in this direction where one solution can be found for road safety.
- Lighting: Theory
- Accident Statistics p106
- Accident statistics issued by the Ministry of War Transport show a reduction in deaths on the road as compared with
the same month the previous year. For July 1945, there were less accidents in the month of partial lighting of "Black out" (1945)
than in the same month of "Black out" (1944). From this fact it may be claimed and proved that lighted roads do reduce
accidents.
- Statistics: Accident Data, Lighting: Safety
- Wilful Damage to Street Lamps p106
- Representation has been made to the Home Secretary and he has undertaken to bring the matter to the notice of
Chief Constables throughout the country. It is hoped that by bringing this matter to the notice of the public and
seeking their co-operation will overcome this menace.
- Lighting: Anti-Social Behaviour
- Extraneous Lighting Near to Airports p106
- Attention is drawn to the Memorandum issued by the Director of Civil Aviation appealing to public lighting engineers
to take appropiate action to prevent street lighting from confusing air crews when approaching an airfield to land. The
same caution is also directed to road traffic control signal lights. (Some of the text appeared in the
previous issue). The Association should also consider the feasibility of the introduction of bye-laws
controlling the erection and operation of illuminated signs.
- The issue of illuminated signs has exercised Authorities throughout the country. It should never be permitted for illuminated
advertising signs to be erected on the frontage of any building unless approved by the appropriate official appointed by the Council.
- Lighting: Specifications
- What Does This Mean? p106
- Mr. R. G. Strauss, Parliamentary Secretary to the Ministry of War Tranport, in replying to the debate in the House of
Commons on the Trunk Road Bill is reported to have said concerning the public lighting on main roads: "The Minister will go into
this question as soon as possible, with the other Government departmetns concerned, with a view to devising a better system." The
complaint had been that the Ministry, having taken over control of certain trunk roads, had refrained from taking any responsibiltiy
for the lighting of such roads. However, it turns out that the Minister was refering to the financial responsibility for lighting
the roads.
- Lighting: Funding, Lighting: Legal
- Lighting Of Bends And Junctions by Francis F. Middleton p107
- A full reporduction of Middleton's paper is included.
- Discussion
- Mr. F. C. Smith (Gas Light And Coke Company): The author had successfully drawn attention to the importance of
backgrounds. Whilst in wholehearted agreement, he felt that the paper so simplified the problem that it might be
misleading. The situation presented was too static and backgrounds were not so clear-cut.
- Mr. V. Hewitt (Rawtenstall): Criticised the reading of papers in full. Suggested only summaries should
be read. (The President said the council would bear that in mind for the future).
- Alderman F. Thraves (Sheffield): The reason most delegates attended Conferences was to take back to their
Committees and Councils information. A paper of this kind was so high technical that it presented a mist of information
which was difficult to sort out. There were two types of mind on all Committees: one so dererential to the
technical man that no one question him; the other that was not convinced by anything. The paper was excellent and
he understood more after the presentation. Still, his mind was a muddle and he did not know how to convince
his Committee. (Incidentally, to see a well lighting city go to Sheffield!)
- Mr. E. L. Leeming (Lighting Engineer, Urmiston): There were many badly designed bends
in this country and the lighting would be much improved if it was super-elevated instead of cambere - in that
case the lighting would be better on the inside of the bend. More economical lighting might be
obtained with more uniform distriubtion if a greater use was made of super-elevation. Junctions
could be lit with a different colour light - this would assist road safety. Most roundabouts were
also badly designed; they were too small and the slope of the road was in the wrong direction. It
should be inwards and this would permit the use of low level lighting on the inside of the bend
instead of high level lighting on the outside.
- Mr. R. Greaves (Lighting Engineer, St. Helens): Disagreed with low mounting heights on
the inside of bends. High level lighting could be seen at a distance and enabled the traffic to
get round bends better. Electric lamps had to be put up high because there was glare from them, but
gas did not need to go so high because there was no glare. A height of 18' was ideal for gas
and the 25' high electric lamps were placed so far apart that there was no comparison. Many lighting
engineers could show exmples of the lightign of bends with two lower power low-mounted gs lanterns
which gave much better results than high mounted electric lamps which produced hare.
- Mr. E. C. Lennox (North-Eastern Electric Supply Co.): Discussion should be kept within
the limits of the paper. The author had talked about background brightness not roadway brightness.
Did the author know of any firms producing lanterns purely for roadway brightness? Personally he
did not know of any firms that were doing that. In the lighting world, everyone was convinced there
must be background brightness.
- Mr. Middleton: Where the brightness varied, the installation was badly designed. Different
coloured lights could cause eye strain due to eye adaptation. Super-elevation of the road surface
would not be necessary if there was good background lighting so that pedestrians could be seen on
the pavement.
- Lighting: Distribution, Lighting: Theory
- A Post-War Course In Illumination And Public Lighting p112
- A special class has started at Stow College School of Engineering by Mr. F. M. Hale, B.Sc.
of the Lighting Department, Glasgow. The course covers the syllabus for the Intermediate
Examination of the City and Guilds of London Examination. It includes:
- 1. Light Production and Control
- 2. The Eye and Vision
- 3. Photometry
- 4. Practical Light Sources
- 5. Illumination
- 6. Distribution and Control System
- Lighting: Education
- Royal Society For The Prevention Of Accidents p112
- Mr. R. G. Strauss, the Parliamentary Secretary to the Ministry of War Transport,
addressed the Public Safety Committee. He made special reference to the forthcoming Road Safety
Campaign and he referred to the 4,459 miles of trunk roads taken over from local authorities
under the Trunk Roads Act 1936, stating that a further 3,700 miles of roadways would be taken over
from the County Boroughs and County Councils upon the passing of the Trunk Roads Bill now before
Parliament. Under the final approval of this Act, no less than 8,150 miles of trunk road will
be under Government control. The question of improved street lighting was also referred to.
- Lighting: Authority Organisation, Lighting: Legal
- The Lighting Of Albion Street, Southwick, Sussex p113
- Details of the the installation and how it conforms with the proposed B.S.I. Specification.
- Lighting: Installations, Lighting: Specifications
- Official Advertisement p113
- Advert for the appointment of a Public Lighting Assistance for the Corporation Of Greenock.
- Lighting: Management
- The Relation Of Public Lighting Safety On The Roads by Norman Axford, B.Sc., A.M.I.E.E. p114
- The total number killed on the roads during the five years of war was 38,970 - an average of 21 killed every day.
How can we, as Public Lighting Engineers, do our part in assisting to reduce this terrible and possibly increasing casualty
list?
- 1. What part does faulty public-lighting play in the causation of street accidents?
- The analysis of the cause of a street accident is a complicated affair. Unfortunately statistics are not kept where
street lighting is named as the major cause of the accident.
- What is the relation of night casualties to day?
- From a special analysis of fatal road accidents during the period April 1936 to March 1937 made by the Ministry of Transport
the results were: Daylight 62%, Dark 38%. Figures were kept during the war years and the Road Accident Bulletin No. 18 published
by the Royal Society for the Prevention of Accidents: this shows the average number of deaths per day on the roads year by year
from 1937 to 1944, and separated between daylight and after dark during the war years. As would be expected,
during the first year of blackout, the average after dark rose from 38% to 54%. In succeeding years, the figures fell to
43%, 39%, 36% and finally 32%. This is largely due to less traffic after dark as the years went by, and the small amount of
"Starlight" lighting would've contributed.
- Other data came from the London Metropolitan Police Authorities, and shows the time of traffic accidents (a) on 260
days, Monday to Fridays, and (b) 52 Saturdays and Sundays, all for 1938. On weekdays and Saturdays, the peak accident times
coincide with the peak rush hours, but on Sundays the maximum figure occurs well after dark.
- It would seem that we might reasonably expect something of the order of 40% of road accidents to occur after dark
in this county if pre-war conditions of lighting and traffic density continue.
- What is the effect of improved street lighting?
- There is no doubt that improved street lighting reduces the night accident rate, but there are so many factors involved
in any accident that to study it scientifically, I suggest it would be of great advantage to the Public Lighting industry,
if a section of a city or length of roadway could be taken, where it is known that the present system of lighting is not good,
and it is intended to carry out improvements in the fairly near future, for an accurate scientific survey to be undertaken
both before and after the improvement. If such a scheme is to be put into effect then the following
items must be included on the accident report form:
- (1)Time of Accident and weather conditions
- The survey should be for twelve months either side of the date of improvement, so that
comparisons of the accident under all conditions likely to be found throughtout the year
can be made.
- (2) An endeavour should be made to assess blame on either driver or pedestrian
- This would enable one to judge whether lighting should be increased in value near
places where large numbers of people are likely to be found.
- (3) A Traffic Census must be taken during the period of test.
- Consideration must be given to the respective volumes of traffic flowing. It should
be sufficient to take figures for a week, say six times a year, as fairly representative.
- (4) Rough Estimate of cost of damage caused
- Allows the cost of improved Public Lighting to be compared with the cost of accidents
occuring prior to its installation.
- (5) Site plan of accident to include position of street lamps if accidents after dark
- This will assist in deciding whether some re-siting is necessary if it were found that
accidents were always occurring under certain similar conditions.
- (6) Speed of vehicles concerned
- This would counter the argument that improved lighting invites higher speeds and hence
more accidents.
- In Detroit, night-to-day fatalities from 2.4 to 1 fell to 1.4 to 1 by installing an
improved lighting system, with the illumination increased 4 to 6 times its previous
value. Safety lighting installed on more than twelve miles of Syracuse Main Traffic
arteries resulted in a night accident reduction of 24.9% over six to eight months. In
Hartford, Connecticut, the night-to-day accident ratio was reduced from 57% to 38%. London
Embankment figures also given. Generally it can be accepted that improved street lighting
will go a long way to reduce the after dark casualties.
- 4. What particular points must be borne in mind in designing a street-lighting layout.
- A well planned installation should :-
- (a) Reveal objects in the path of vehicles within the limit of the driver's abiliy to take appropiate action and stop
if necessary.
- (b) Reveal persons on the footpath clearly so that the driver can have some intimation of their probable future action.
- (c) Indicate clearly side roads and danger points.
- (d) Give these results under varying weather conditions.
- The functions of modern street lighting may be summarised as: 1. For the safety of road users; 2. For police purposes; 3. For
the convenience of residents; 4. For emphasising some particular area i.e. a civic centre.
- The MOT recommended two classes of lighting: Group A for main traffic routes; Group B for other roads.
- Main Traffic Routes
- The lighting of these should be such that there is adequate safety for all road users without headlights being used.
This means driving at 30m.p.h withotu headlights the driver must be able to see the road ahead clearly and be able to
define any object on it in sufficient time to avoid it at that speed.
- Objects are generally seen as dark against a light background. The well-designed layout should provide a bright road surface
so that the objects on it appear in silhouette. The brightness of the road is obtained by placing the light sources in
such a position that the light is reflected at a very oblique angle and the patches of reflected light from each unit merge
together. The siting and design of lanterns must be such that glare is the driver's eyes is reduced to a minimum.
- The road surface is not the only background against which objects will be seen, particularly on bends. Therefore street
lighting should also ensure that footpaths, buildings, fences etc. adjacent to the roadway appear light in colour so
pedestrians about to cross the roadway can be spotted. This is sometimes difficult to obtain in practice and can be overcome
by using white or chequered boards.
- On bends, it follos that to obtain the patch of reflected light, the light sources must be placed on the outside of the
curve. Getting the patches to merge uniformally is part of the Public Lighting Engineer's art.
- Where thoroughfares have heavy foliage lining them, it may be difficult to adopt side mounting of the light sources,
and it may be necessary to adopt central suspension.
- Other roads
- Because of the lower traffic density these do not present so much danger as the main traffic routes. The same general
principles remain. Too often when residential housing estates are laid out, street lamps are placed haphazardly along the
roads, resulting in patches of light and darkness, a frequent cause of accidents.
- Maintenance
- The lighting will fall off rapidly unless a regular cleaning and maintenance programme is maintained. I would stress
the advantage of changing all lamps on a regular routine when they have completed their guaranteed life. This maintains
the standard of lighting but reduces "Outs" which may be the cause of accidents.
- Cost of Installation
In Hartford, Connecticut, records of the costs of accidents were kept. It was shown that an increase of 8425 dollars
per annum in street lighting resulted in a decrease of 36550 dollars in the cost of accident damage. For human lives,
it is not possible to put a value on these, but six people were killed after dark every day last year in the UK, around
2000 deaths per year. If improved street lighting were able to reduce this by only 50%, would it not be worth while
spending what is, a very small sum, to say that at the end of the year 1000 people are alive today who might otherwise
be dead?
- In order to give some idea of the actual cost of a properly laid out installation in a town
of 200,000 inhabitants, the following approximate figures may be of interest. The town has 23 miles
of main traffic routes and 200 of 'otherroads'. To attain the standard of illumination laid down
in the Final Report of the MOT, I have assumed (a) on the main roads, 250W mercury lighting at
150' spacing; and (b) 100W metal filament lamps at 120' spacing. If costs were about 30% above
pre-war, the approximate costs would be: (a) main traffic routes £12,350 per annum; and (b)
other roads £55,675 per annum. I have assumed all-night running. The total figure may appear on
the high side, but the result would be a public lighting installation of which the town would
be proud and would certainly bring about a marked drop in after dark accidents.
- Reusing solumns on side roads a saving of £2,500 per annum could be made. It might be
possible to extend the spacing a little along the other roads, saving a further £6,500 per annum.
This would bring the final total to £46,675 per annum or just under 5s per annum per head of
population Surely this could be afforded?
- In 1939, when faced with the possibility of death and injury from air raids, approximately
a third of a million pounds were used as capital expenditure only to save life as far as possible.
It doesn't seem possible to do this in peace time, but surely we should be prepared to
spend £100,000 to save life?
- Conclusions
- 1. There is no doubt that a properly planned street lighting installation will
result in an appreciable decrease in night traffic risk.
- 2. That it would be well worthwhile carrying out properly conducted tests to
investigate the actual relationship of street lighting to accidents.
- 3. That although correct lighting costs money, its installation will result
in saving to the community as a whole.
- Lighting: Funding, Lighting: Safety, Lighting: Statistics, Lighting: Theory, Statistics: Accident Data
- Street Lighting Control: A Description Of The "Record" Control System p119
- System devised after careful consideration of the advantages claimed by several existing systems. The
greatest advantage claimed is that no additional wiring is required. In many districts,
pilot wires are already in existence, while where new cables are being laid the cost
of the extra core is almost negligible. Therefore they developed a scheme which
would be simple in optionation, and therefore cheap, and would use the pilot wire
to transmit impulses so would be free from external interference.
- The outcome was the "Record" Remote operated Selective Switching Unit. It does
not depend on an operating current which is different in frequency or voltage from
that alreadying existing on the L.T. network, which overcomes the trouble of maintenance,
since it does not require technical knowledge outside the sphere of lighting.
- It depends on its operation purely upon an impulse of approximately 5 seconds
along the pilot wire, the potential being any existing L.T. phase voltage at normal
frequency or D.C.
- The Transmission Of Impulses
- The simplest form of impulse transmitter is an ordinary push button connecting phase to pilot and operated by hand to
switch "on" and "off" the whole of the lighting. This suffers from the disadvantage that there is no visual indication of the
lighting position and relies on the human element for its operation at any time. This is overcome by housing in one box the appropriate
number of receiving units with control lights, which indicate the lighting position at any time. In addition, there is a time switch
which times the impulses to suit the requirements. A push button is provided for use in emergencies, such as fog conditions etc.
- The Receiving Unit
- This is a solenoid operated switch which has been designed to have its contacts open or closed in any predetermined sequence
with a maximum cycle of eight different positions, after which the cycle is repeated. This cycle is brought about by the solenoid
plunger operating an eight-toothed lantern pinion which carries a cam, which in turn opens or closes the contacts, according to the
shape of its periphery. Therefore by fitting different shapes of cam, any combination of lighting can be arranged to suit up to
eight different conditions. This can be used both to accommodate partial switching off for skeleton lighting after midnight, and
for gradual switching on, so that the full lighting load is not suddenly switched on without warning. The contacts of the switches
are of pure silver and there is considerable pressure between the contact faces when they are closed. A pair of contacts would stand
several hundred thousand operations while controlling a load of 400 watts without undue burning. There is also a patented mechanism
coupling the pawl on the solenoid plunger to the lantern pinion, or rotor, which prevents the latter from overshooting. This makes
it possible to put plenty of reserve power into the solenoid without fear of its momentum carrying the rotor round too far.
A switch wound to operate off 230 volts, 50 periods, will still operate on a voltage as low as 160. Also, as part of the mechanism is
a non-return pawl on the rotor to prevent it for either move round and getting out of position due to vibration, or being pushed
in the reverse direction due to pressure from the contacts. The contact operating cam is easily changed at any time if
a different programme of lighting is required. The whole is housed in a neat brass cover which is designed to overcome
open-air conditions.
- Operation on Non-Pilot Schemes
- The system can be operated on a two-wire system. The limitations are (i) the two wires must be for lighting distributions
i.e., not general service mains and (ii) that the operation of the scheme depends upon a momentary interruption of the circuit,
it cannot be used to give suitable control of mercury vapour lamps. Discrimination of lighting is acheived by breaking the
supply to the two wires, which allows the solenoid plungers to fall, and then quickly restore the supply which energises the
solenoid, thus turning the cam around to the next position. The break in the two-wire circuit can still be initiated
from the central control point by an impulse.
- Lighting: Control
- London Street Lights To Stay p121
- London boroughs rejected for reasons of public safety and security the recent appeal from the Ministry of Fuel to
switch off street lighting at midnight. Every London road will be lit throughout the winter nights; main roads will be
well lighted and side streets partially lit. At the same time, borough councils will co-operate with the Ministry to
drive to conserve coal by maintaining street lighting at half the pre-war standard. An official of the Ministry of Fuel
said: "Our object was to bring about that economy by cutting down consumption. Our objective will have been achieved.
- Lighting: Energy
- The Appointment Of A Public Lighting Engineer p121
- The Public Lighting Engineer is now a recognised professional official and several of the chief cities in this country
have appointed such men to take over full control of all street lighting within the cities' boundaries. The work involved
in planning a modern street lighting installation requires the services of an expert. Whilst such services are available from
the manufacturers - it must be agreed that the lighting authority is invariable left to the mercy of such advisers,
who view every lighting installation with a commercial bias. There is little doubt that in these post-war years when street
lighting becomes still more advanced, and when new lighting equipment becomes available, and still brighter lamps are put on
the market, the services of a qualified public lighting engineer of the type as already indicated will become a real neceesity
and will be in great demand.
- Lighting: Management
- Clockwork Controllers: Repairs p121
- Textural advert for J. W. and R. E. Hughes (Clockwork Engineers)
- Other
- A Stair-Lighting Threat p121
- Street lighting officials in Greenock have threatened to cut off all stair lighting unless the vandalism of gas mantles
ceases at once. In preparation for the winter, stairhead lamps were overhauled. Now hundreds of the mantles have been destroyed.
A greet deal fo the damage has been done by people lighting cigarettes or pieces of paper from the mantles.
- Lighting: Anti-Social Behaviour
- War Loss And Patents p122
- Report on changes to war damage applications and extention of patent terms under Section 18 (6).
- Other
- Adverts:
Poles Ltd,
The Association Of Metal Sprayers,
Stanton Ironworks Co., Ltd,
Siemens Electric Lamps And Supplies Ltd.,
Metropolitan Vickers Electrical Co. Ltd,
Engineering And Lighting Equipment Co. Ltd.,
Holophane Ltd.,
British Gas Council,
British Electrical Development Association, Inc,
The Record Electrical Company, Ltd.,
C. H. Kempton and Co., Ltd.,
The British Thomson-Houston Co. Ltd.,
The Horstmann Gear Co., Ltd.,
Automatic Telephone And Electrical Co., Ltd.,
William Sugg And Co., Ltd.,
Crompton Parkinson Ltd.,
Sordoviso Switchgear Ltd.,
British, Foreign And Colonial Automatic Light Controlling Co., Ltd.,
Girlings Ferro-Concrete Co. Ltd,
APV Aluminium Castings,
Hobbs, Offen and Co. Ltd.,
Falk, Stadelmann Co., Ltd.,
E. K. Cole Ltd,
Brighton Lighting and Electrical Engineering Co. Ltd,
Peebles Co., Ltd.,
J. W. & R. E. Hughes,
APLE Conference Papers Bound Sets,
Sangamo Weston Ltd. and
The General Electric Co., Ltd.
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