A road-lighting specification is not a wattage shopping list. The right luminaire is selected from the road geometry, mounting arrangement, target lighting class, maintenance plan and local electrical conditions. This guide gives project buyers a disciplined way to compare LED street lights before issuing an RFQ.

Start with the road, not the fixture

Collect the road width, number of lanes, pole height, arm length, pole spacing, pavement type, intersections, pedestrian crossings and surrounding ambient light. These inputs let a lighting engineer model the installation rather than guess from a catalogue image. For a municipal street, the design question is whether the road meets the target average luminance or illuminance, uniformity, glare and visual guidance. For industrial roads, shift-change traffic, gates and vehicle manoeuvring areas may require a different solution from a straight public road.

Choose optical distribution before nominal wattage

Optics place the usable light on the task area. A Type II pattern often suits narrower roadways, Type III can suit wider roads and parking edges, while Type IV or V may be relevant for perimeter and area-lighting layouts. The final choice must be verified in a photometric calculation with the actual IES/LDT file. A 120 W product with unsuitable optics can perform worse than a lower-wattage luminaire with the correct distribution, because more light is wasted outside the target area.

Use wattage as an output of the calculation

LED count and input wattage help narrow a product family, but they do not define delivered performance. Compare luminous flux, efficacy, drive current, CCT, CRI, lumen-maintenance data and the photometric result at the planned mounting height. Ask whether the quoted lumens are fixture output or LED-chip output. The latter is not a fair comparison. Good RFQ documentation states the required installation result, then allows the supplier to recommend a configuration with a traceable photometric file.

Specify electrical and environmental protection

For outdoor project work, buyers should confirm ingress protection, mechanical impact rating, surge protection and the intended grid conditions. IP66 and IK09 are common project requirements where dust, rain and handling impact are relevant. Surge-protection selection should reflect local exposure and the project electrical design; a supplier should state the nominal rating and the replacement or service approach. Do not treat a surge label as a generic promise: request the component specification and test evidence appropriate to the order.

Review the mechanical installation details

Check spigot diameter, tilt adjustment, cable entry, tool access, windage, housing material, corrosion protection and the weight that the pole can accept. Installation preparation is smoother when the luminaire, pole, bracket and cable-gland interfaces are reviewed together. If a project uses both side-entry and top-entry poles, identify this before production. A small adapter decision made late can delay an otherwise ready shipment.

Ask for a project-ready document pack

Before you compare offers, request a datasheet, dimension drawing, IES/LDT file, wiring information, installation instructions, photometric proposal, quality-control plan and commercial terms. During factory testing, the supplier should be able to trace the configuration being inspected. Before shipment, confirm the carton marks, accessory count, spare parts and packing method against the purchase order. These checks reduce the risk that the model approved in the calculation differs from the delivered item.

A practical RFQ checklist

Include location and climate, road layout, pole layout, target standard or performance requirement, quantity, voltage and frequency, CCT/CRI preferences, control requirements, requested protection ratings, delivery date and destination. Add project drawings where available. With these details, a supplier can return a useful proposal instead of a generic wattage table.

Conclusion

The strongest street-light purchase decision connects application geometry to optics, verifies performance with photometric files and confirms that the mechanical and electrical details work on site. Treat the RFQ as an engineering brief and you will receive more comparable, lower-risk proposals.

FAQ

Questions buyers ask

Is a higher wattage LED street light always brighter on the road?

No. Road performance depends on fixture output, optical distribution, mounting geometry and light loss. Use a photometric calculation to compare options.

Which files should a supplier provide for a lighting calculation?

Request the IES or LDT photometric file, the product datasheet and dimensions, then validate the calculation against the proposed pole arrangement.

What should be checked before shipment?

Confirm the approved model, power, optics, CCT, accessories, labels, cartons and inspection records against the purchase order.