The origins of street lighting go back to Roman and Ancient Greek times, when oil lanterns would line settlement streets. Slaves would light up the lanterns that were found outside their masters' villas and other important facilities, providing security as well as improved safety.
Such techniques would be used on and off through the ages; however the Industrial Revolution would change such methods. Gas soon took over as the favoured option, with the first large scale installation being carried out in Golden Lane, London during 1807. However, workers were still needed to light the supply at dusk, then to "snuff" the flame when dawn occurred.
The next step forward was the creation of an electric lantern. Pavel Yablochkov, a Russian engineer, developed an arc lamp in 1875, which provided a powerful source of lighting. The downside was that the lanterns were too bright for everyday street usage, and required intensive and regular maintenance. They were great for dockyards, however!
1879 saw the creation of the incandescent lamp by Joseph Swan, who established the world's first fully-lit street in Moseley Street, Newcastle-upon-Tyne. This type of lighting became an immediate success, and cities worldwide turned to using this type of lantern.
The gradual spread of street lighting across the UK led to the first set of national standards being established during 1927. Due to efficiency and economic constraints, the standards required lighting accompanied by reflectors which would direct all light into a narrow channel in the roadway. This resulted in no uniform illumination of the roadway, causing pavements and large parts of the carriageway to remain unlit. And a large amount of glare where the road was lit!
However, the standards would soon become outdated due to the rapid development of new types of lighting. Philips would lead the way with the introduction of their sodium bulb in 1933, which had the benefit of producing less glare than their incandescent counterparts. This was quickly followed by the development of the “cut-off lantern” by Wardle of Manchester, which came with one downside – it could only channel light straight down, so needed to be suspended over the centre of the carriageway.
Then in 1935, Philips demonstrated the first high-pressure mercury bulb; other manufacturers saw the benefit of this option, with several (including Philips) launching the first commercial models in 1937. Two years later, fluorescent bulbs would also emerge on the market.
|Recommendation for the Lighting of Traffic Routes (Group "A")|
|Mounting Height||To centre of light source, 25 ft.|
|Spacing||Generally not greater than 150 ft., but under occasional span may be as much as 180 ft. Where economically possible, spacing at 120 ft. may be adopted. For cut-off lighting, a figure substantially below 150 ft. is required.|
|Overhang||Maximum distance between the two rows should not exceed 30 ft. Maximum overhang of 6 ft. This is to allow the lighting of kerb, pavements and adjoining property.|
|Amount Of Light||For a carriageway of not more than 40 ft. in width, luminous output per 100 ft. linear of road should be between 3,000 and 8000 lumens.|
|Distribution Of Light||Available light should produce the maximum contrast between brightness of the object to be used, and its background.|
|Glare||With non-axial distribution, ratio of peak candle-power to the average of the values in all directions downward from the source and lying between 30 and 45 from the vertical should not exceed 6. With axial distribution, the ratio should not exceed 5.|
|Siting Of Columns||Single side lighting should be avoided except on bends and central suspension.|
|Recommendation for the Lighting of Non-Traffic Routes (Group "B")|
|Owing to wide variations that exist for these roads, general guidelines rather than specific guidelines are given.|
|Mounting Height||Between 13 ft. and 15 ft.|
|Spacing||Not greater than 120 ft, with maximum of 150 ft. in exceptional cases. Where economically possible, spacing at 100 ft. should be adopted.|
|Amount Of Light||Between 600 and 2500 lumens per 100 ft. linear of road.|
|Distribution Of Light||As Group 'A'.|
|Glare||For Non-Axial fittings, the ratio should not exceed 4. With axial distribution, the figure should not exceed 3.|
|Siting Of Columns||Staggered system recommended, with special care at junctions and intersections.|
Following the war, lantern and column designs would become regulated; 1946 would see the Royal Fine Arts Commission being given the final say on what could be marketed. This led to a restriction in the use of steel, so concrete columns became much more popular
Despite this meaning a case of design over practicality, this arrangement was kept in place until 1952, with the regulation being passed to the Council of Industrial Design. This change was brought in at the same time as the government introducing a new Code of Practise, which established a new set of standards for Group A roads; part two of the Code, covering Group B roads, would not be published until 1956. Although generally keeping the framework of the 1937 report, it made changes where developments in both lanterns and columns meant the original requirements became outdated.
Regardless of the regulations and limitations, street lighting continued to become increasingly popular. By 1954, nearly 48,000 miles of roadway in the UK was illuminated:
- 23,100 miles Tungsten filament
- 20,000 miles Gas
- 3,060 miles Mercury Vapour discharge
- 1,570 miles Sodium discharge
- 250 miles Fluorescent
The continuing improvement of lighting was causing problems for the government, as the Code of Practise was quickly becoming out-dated. Newly released bulbs were noted for their efficiency, yet they were somewhat too efficient – current mounting heights were simply too low for their use. However, the opening of the Preston Bypass in 1958 led to an opportunity to create a new “Super Group A” tier for motorways and major arterial routes – despite the Preston Bypass not being lit!
From then on, the development of better, more efficient lighting continued. The General Electric Company released the first high-pressure sodium lighting in 1967, following a successful trial the year before in Wembley. The market potential meant that other manufacturers quickly followed suit.
Despite this, it would be another 20 years before they really started to become widespread, with many authorities limiting their use to pedestrian crossings and shopping areas – low pressured lighting would still be used in most places.
Nowadays, most authorities are replacing older lanterns with high-pressure sodium lighting as part of lighting improvements – they are seen to make roads safer as road users can see colours more clearly (not just shades of orange), plus provide a better light coverage as they create less glare. In the past few years, this type of lighting has been joined by metal halide and LED lighting, which produce an even purer white colour.
The fifties saw a complete change in the development of street lighting. New high-intensity discharge (HID) lanterns would provide an increase in illumination, but despite being similar to arc lighting, they were nowhere near as bright as the earlier bulb. And unlike earlier lighting types, there was a choice of HID lamp types.
Lighting standards today mean that all luminaries (the term now used instead of lantern) on UK roads need to conform to a set of requirements laid down by the Government. Although the requirements are specifically aimed at trunk roads and motorways, local authorities also tend to follow these guidelines.
In addition, when new lighting is installed, there are a number of issues that need to be assessed:
- will the lighting help to improve safety;
- the cost of purchase, installation and maintenance;
- energy usage and costs;
- ease and cost of removal and disposal when they need replacing.