How do 12-inch traffic lights compare with 8-inch and 16-inch signals?
Published 27 March 2024 · Updated 13 October 2026
A 12-inch traffic light has a larger nominal signal face than an 8-inch light and a smaller face than a 16-inch light. In the GAOQIAO catalogue, these size classes are labelled 300mm, 200mm and 400mm respectively. The label describes the signal face size, not the height, width or depth of the complete signal head.
| Catalogue size | Nominal inch label | What to compare |
|---|---|---|
| 200mm | 8 inch | Required indication, housing fit and mounting interface |
| 300mm | 12 inch | The same items, using the drawing and optical data for the 300mm version |
| 400mm | 16 inch | Project approval, assembly clearance and mounting requirements for the larger version |
The inch labels are nominal catalogue equivalents. Exact inch-to-millimetre conversions are 203.2mm, 304.8mm and 406.4mm. For a replacement, use the manufacturer's dimensioned drawing rather than treating the nominal label as an exact fit measurement.
Does 12 inch describe the whole traffic light?
No. It describes the nominal signal face. Overall dimensions depend on the aspect count, housing, visor, bracket and arrangement. A three-aspect head and a single-aspect head can both use 300mm faces while having different overall dimensions. Ask for the complete assembly drawing.
Is a larger signal automatically better?
Diameter alone does not establish visibility, power consumption or suitability. Review the approved project specification and optical documentation for the actual round or arrow indication. Do not choose a diameter solely from a state name, traffic volume or an assumed universal viewing distance.
For a US road project, consult the applicable FHWA MUTCD edition and the requirements of the responsible road authority. An available catalogue size does not establish approval for a particular installation.
What should I send for a replacement or new order?
Send the country, project specification, required face size, round or arrow indication, aspect count, supply voltage and quantity. For a replacement, add photos and measurements of the existing housing, module retaining points, visor and brackets.
Compare the 200mm LED traffic light range and 300mm LED traffic light range. For a detailed purchasing workflow, read our traffic light size selection guide.
Request a model drawing or send your project details to sky-sale@njgq.net.
A replacement comparison that goes beyond lens diameter
Check the complete dimensions
For a replacement enquiry, provide the existing signal label, a front photograph and a drawing or measurements of the mounting arrangement. Record the full assembly height, width, depth and bracket spacing separately from the nominal lens diameter. Similar-size lenses can be housed in different assemblies.
Also identify the symbol and colour arrangement. A circular signal, an arrow and a pedestrian display may share a diameter while serving different purposes. The approved project specification should determine the indication and performance required at the installation.
Match the electrical and service details
State the available supply and identify the controller or other equipment driving the head. Confirm the connector, wiring and any countdown or dimming interface with the supplier. Avoid treating a change in lens size as a simple substitution until these interfaces have been reviewed.
Ask whether the proposed assembly includes brackets, visors and cable fittings, and which spare modules match it. Compare the final drawing and data sheet before ordering. Keeping these records with the equipment list helps prevent later replacements from being selected solely by a catalogue size label.