Buying a traffic signal is not the same as buying a lamp. The signal head, controller, pole, cable and intersection plan must work as one system. Most quotation problems begin when the inquiry names a diameter and color but leaves out the operating sequence, input voltage, mounting arrangement or approval documents.
This guide is written for contractors, distributors and project buyers preparing an LED traffic signal inquiry. It focuses on the decisions that affect fit, control and acceptance, so offers from different suppliers can be compared on the same basis.
1. Start with the traffic movement
Describe who or what the signal controls before choosing a catalog model. A vehicle ball signal, protected-turn arrow, pedestrian figure, bicycle symbol, lane-control cross, warning beacon and countdown display may share a housing size but perform different jobs. Attach an intersection or site plan and label each required signal group.
| Project question | Information to provide | Why it changes the offer |
|---|---|---|
| Who sees the signal? | Vehicles, pedestrians, bicycles, lane users or site traffic | Determines symbol, color and viewing requirement |
| What must they do? | Stop, proceed, turn, wait, clear a lane or observe a warning | Defines the indication set and sequence |
| Where is it installed? | Public road, work zone, tunnel, gate, factory, port or car park | Affects mounting, environment and approval path |
| How is it controlled? | Traffic controller, relay, sensor, barrier, remote or standalone flasher | Determines voltage, wiring and interface |
2. Choose the indication and number of aspects
An aspect is one optical face. A standard vehicle head commonly uses three aspects—red, yellow and green. Two-aspect heads are used for clear stop/go applications, while one-aspect housings suit dedicated arrows, lane symbols, pedestrian/bicycle faces and countdowns. A fourth aspect may add a protected arrow, countdown or project-specific indication.
Do not order from the aspect count alone. Mark the color and symbol of every face on a front-view drawing. You can compare the dedicated 1-aspect, 2-aspect, 3-aspect and 4-aspect catalog pages.
3. Select the face size using the project conditions
Common visible diameters include 100 mm, 200 mm, 300 mm and 400 mm. The final choice should follow the governing specification and consider approach speed, viewing distance, lane width, background clutter, mounting offset and the road authority’s approved drawings. A larger face also creates a larger housing and more wind area, which can affect pole and foundation design.
Ask the supplier for the overall housing dimensions, not only the lens diameter. Our traffic light size guide explains how to compare the four common sizes without treating diameter as the only visibility factor.
4. Match the electrical design to the controller
State the nominal input voltage, permissible range, AC or DC supply and frequency where applicable. Include the controller model or output diagram. A signal designed for a low-voltage solar system cannot be substituted for a mains-driven cabinet output simply because the housing looks identical.
For each face, clarify whether the controller switches a separate circuit, whether dimming or flashing is required, and what should happen if the controller or communication link fails. Countdown displays need an additional interface decision: signal-wire learning, dedicated timing output or data communication. See the countdown timer selection guide.
5. Specify housing, mounting and site exposure
- Orientation: vertical or horizontal, with the approved color order.
- Mounting: pole, mast arm, wall, bracket or portable frame; include the pole diameter and bracket drawing.
- Cable entry: rear, top, bottom or bracket-fed, with terminal access requirements.
- Housing: material, color, visor style, front or rear service access and replaceable parts.
- Environment: operating temperature, rain, dust, salt, strong UV, vibration or industrial contamination stated by the project.
Ask how the enclosure rating applies to the assembled signal, including cable entries and service doors. A component rating by itself does not describe the final installed enclosure.
6. Request evidence for the exact offered model
Public-road tenders may reference standards such as EN 12368, ITE vehicle traffic signal head requirements or GB 14887, depending on the market. Do not accept a generic certificate list as proof for every product. Ask the supplier to identify the model on the offer and provide the corresponding drawing, wiring diagram, declaration and test evidence required by the tender.
Also check the report scope: face size, color, housing, voltage and product family should match the item being purchased. If a local approval or third-party inspection is required, put it in the inquiry before pricing.
7. Build an RFQ that suppliers can answer consistently
A useful bill of quantities should contain one line for each distinct signal configuration. For every line, include:
- Quantity and delivery destination.
- Face arrangement, color and symbol drawing.
- Visible diameter and overall dimension limits.
- Input voltage, controller output and operating mode.
- Housing orientation, visor, bracket and cable entry.
- Required standard, language, labels and document package.
- Spare modules, visors, gaskets, brackets or tools needed for maintenance.
For a complete intersection, add the number of approaches, phase plan, pedestrian movements, detection inputs, cabinet requirement and communication needs. The controller RFQ checklist provides a separate worksheet for that part of the system.
8. Compare offers beyond unit price
First check that every supplier priced the same face size, voltage, housing, bracket and document scope. Then compare replaceable parts, terminal access, drawings, test evidence, sample approval, packing, lead time, warranty terms and spare-part availability. An inexpensive signal that needs a new bracket, converter or controller output can cost more after installation.
For customized symbols or housings, approve a dimensioned drawing before production. For a new supplier or unfamiliar model, a production-representative sample helps verify wiring, mounting and workmanship before the full quantity is released.
Frequently asked questions
Which LED traffic light size should I choose?
Use the size required by the project or approving authority, then check it against viewing conditions and mounting geometry. Do not choose by road width alone.
Can one controller operate signal heads from another manufacturer?
Often yes, but voltage, switching method, load behavior, monitoring and terminal allocation must be compatible. Exchange wiring diagrams before confirming the combination.
What is the difference between a ball and an arrow signal?
A ball generally controls the permitted movement for an approach, while an arrow applies to a defined direction. The phase plan and local rules determine when each indication may run.
Should spare LED modules be ordered with the project?
For remote sites or a large installed base, project-specific spares reduce downtime. Base the quantity on the number of each unique module, local maintenance capacity and the expected support period.
What should I send for a fast quotation?
Send the bill of quantities, front-view signal drawings, voltage, controller or phase plan, mounting details, required documents, destination and target schedule. Use the project inquiry page to attach or describe these details.
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