Arrangement of luminaries
The next table shows the most used type of arrangement according to height-to-width Ratio:
Street lighting arrangements
Two way traffic roadsThere are four basic types of street lighting arrangements, which can be summarized in the following points.
Single sided
This type of arrangement, in which all luminaries are located on one side of the road, is used only when the width of the road is equal to, or less than the mounting height of the luminaries. This is shown in the next figure.
Staggered or zigzag array
This type of arrangement in which the luminaries are located on both sides of the road in a staggered or zigzag arrangement is used mainly when the width of the road is between 1 to 1.5 times the mounting heights of the luminaries.
Opposite double side array
This type of arrangement, with the luminaries located on both sides of the road opposite to one another, is used mainly when the width of the road is greater than 1.5 times the mounting height of the luminaries.
Middle one side array
This type of arrangement, with the luminaries suspended along the axis of the road, is normally used for narrow roads that have buildings on both sides.
Curves
Curves of large radius (in the order of 300 m) can be treated as straight roads and the luminaries can be sited in accordance with one of the schemes outlined above.The locations of luminaries on curves of smaller radius, however, should be such as to ensure both adequate road-surface luminance and effective visual guidance. Where the width of the road is 1.5 m less than the mounting height, the luminaries should be placed above the outside of the curve in a single sided arrangement.
For wider roads an opposite arrangement should be used since the staggered arrangement gives visual guidance, and should therefore be avoided.
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