Street Light Pole Height and Spacing: how to plan an even, safe layout

Why pole height and spacing are planned together

A street light does two jobs. It must put enough light on the road surface, and it must spread that light evenly so there are no dark gaps between poles. Height and spacing both control this. A taller pole lets one fitting cover a longer stretch of road. A shorter pole needs to stand closer to its neighbour. Change one, and the other has to change with it.

That is why a request for “an 8 m pole” is only half a brief. The other half is how far apart the poles will stand, which side of the road they are on, and which luminaire they carry. On our street light pole page the series are listed from 3 m to 12 m in conical, octagonal or round shapes, with single-arm, double-arm or custom arm layouts. The pole is the easy part to buy. The layout is the part to plan.

This guide is general. It does not replace the lighting design for your road, the specification in your tender or any rule that applies at your site. Where we give a number, it is a starting point to discuss, not a standard.

Mounting height, pole length and what a quote really means

People use “pole height” for three different things, and mixing them up is a common reason a layout does not work on site. Before you compare any two offers, make sure they use the same one.

An arm that rises, a bracket that tilts the fixture, or a base plate sitting on a raised foundation will each move the real mounting height by some amount. So write down all three numbers for the project and say which one you mean when you ask for a price. Our street light pole price guide explains why height is also one of the main things that decide a quote, along with weight and finish.

How to choose the pole height

Our own FAQ says it plainly: a higher pole is not automatically the right choice for every road or outdoor area. Height should be considered together with the LED fixture and the place of installation. Four questions usually settle it.

How wide is the area to be lit? A narrow internal lane and a wide carriageway with a median do not need the same pole. What is the fixture? A fitting with a wide, even beam behaves differently from a narrow one, and its manufacturer can supply the light distribution data. What is in the way? Tree canopies, balconies and buildings close to the road can shade the light or catch the glare. Who has to maintain it? A very tall pole needs proper access equipment for every lamp change or cleaning visit.

These bands are the ranges buyers commonly talk about. They are indicative, they come from practice and not from a standard, and they are not a statement of what we stock for each use. The height for your road comes from the lighting calculation.

How spacing is worked out

Light spreads out as it leaves the fixture. The inverse-square law says that the intensity from a point source falls with the square of the distance, so a surface twice as far from the light receives only a quarter as much. This is why the road directly under a pole is brighter than the road halfway to the next one.

What a designer checks is illuminance, the light falling on a surface per unit area, measured in lux. The measurement science behind it is called photometry, which weighs light by how bright it appears to the human eye. In a photometric layout the software combines the fixture's light distribution data, the mounting height, the spacing and the road width, and reports the light level and how evenly it is spread.

You do not need the software for a first estimate. A common starting point is to space poles about three to four times the mounting height. It is a first guess, not a design rule.

Layouts: one side, staggered, opposite or central

Spacing along the road is one question. Where the poles stand across the road is another, and it changes the pole count and the arm you need.

On a narrow road, poles on one side can be enough. As the road gets wider, designers often move to staggered or opposite poles so both edges stay lit. On a road with a median, double-arm poles on the median can light both carriageways from one line of poles. Our street light pole page says single-arm poles suit light needed mainly on one side, and double-arm poles suit light in two directions, so the layout also decides the arm.

The pole count changes a lot between layouts, and so does the cost. Opposite poles roughly double the count for the same spacing. That is worth knowing before a budget is fixed.

What changes the number: bends, junctions, trees and the road

The three-to-four rule is for a straight, clear road. Real roads are not. Several things usually pull spacing closer or push the height up.

None of these can be solved by a rule of thumb. They are the reason a photometric layout is worth doing before you order, not after the poles are in the ground.

Taller poles, wind and the pole itself

A taller pole is not just a longer tube. The fixture and the arm catch the wind high above the ground, and the pole carries that load down to its base, plate and foundation. The higher the fixture, the larger that bending effect becomes, so a taller pole needs a stronger section, base and foundation, and usually weighs more.

That is why height links back to the pole's own numbers. The 410 SP tubular pole table guide lists the designations with their section sizes, weights and loads, so you can see how those values change from one pole to the next. Use it as a reference when you ask for a pole to match a height and a load. The material and finish matter too, because a tall pole that rusts at the base is a poor saving. Our MS vs GI lighting pole comparison sets out the choice.

Tell your supplier the fixture weight, the arm length and the site, so the pole is checked for the real load and not only for height. The foundation drawing must match the pole you actually receive.

Plan your layout: spacing estimator and what to send

Use this tool for a quick first estimate of spacing and pole count. It applies the three-to-four times rule from section 4. It is a planning aid, not a design.

When you are ready to ask for a quote, send the details below. A supplier can only quote the right pole if the brief says which height you mean.

For light levels and recommended practice, many designers refer to the publications of bodies such as the Illuminating Engineering Society, which develops lighting standards and recommended practices. Your tender or local authority may name a different document, so follow the one your project specifies. When you are ready, send your details through our contact page and our team in Bhopal will reply in writing.

Frequently asked questions