Introduction
A traffic signal visor shades the lens and can help reduce unwanted sunlight effects, including sun phantom, where reflected sunlight makes an unlit signal appear illuminated. Performance depends on visor geometry, optics and installation. This guide compares three common visor types; it does not establish a guaranteed reduction in crashes.
Tunnel Visor
A tunnel-style visor surrounds the optical face and can restrict unwanted light from some directions. Evaluate its effect with the actual lens, module, mounting and viewing geometry. Confirm the specified sun-phantom performance through applicable evidence for the assembly. Do not assume it blocks sunlight from every unwanted angle or is the best option for every vehicle approach.
Ask GAOQIAO to confirm the material, UV-resistance information, colour and installation state of the tunnel visor for the selected signal head. Identify whether the quoted visor is supplied pre-installed or separately. Do not assume that every head includes the same visor, material or colour options.
Cowl Visor
A cowl visor is a partial hood that extends from the top of the lens downward. It blocks sun from above but not from the side. Cowl visors are used where the approach angle is mostly from one direction (e.g., a one-way street).
A cowl visor may differ from a tunnel visor in dimensions, weight, cost and optical behaviour. Compare the specified assemblies under the required viewing and lighting conditions rather than assuming one type always provides better sun-phantom performance. Ask GAOQIAO to confirm available visor options for the selected signal head.
Directional Visor
A directional visor is shaped to limit the visibility of the signal to a specific lane. Used on closely-spaced signals where a signal intended for one lane might be visible to drivers in an adjacent lane. Less common than tunnel or cowl.
Visor Length and Sun Phantom
Visor length (the depth of the hood) is the main lever for sun-phantom protection:
- Select the visor length from the complete signal’s optical design and required viewing conditions. A 100mm visor is not a universal minimum or proof of suitability for low-angle sunlight; confirm the actual assembly’s test evidence and installation requirements.
- Confirm the visor length from the selected model and project visibility requirements; 150mm is not a universal standard for most regions.
- For high solar angles or summer conditions, assess the visor with the actual optical assembly and required visibility. Confirm its length from the approved design; do not apply a universal 200mm visor solely from latitude or season.
- For strong low-angle sunlight, assess visor geometry with the complete optical assembly and required viewing angles. Confirm the selected visor length from the approved design and test evidence rather than assigning a universal 250mm+ visor to equatorial or tropical sites.
Confirm available visor depth and geometry with GAOQIAO for the selected signal head and required viewing field.
Featured Products
GAOQIAO supplies signal headswith visor type and any optional directional accessories confirmed for the selected model. See thetraffic signal IP ratings guide for related ingress protection.
Conclusion
Compare visor designs using the actual signal head, viewing direction, background and sun exposure. Request evidence for the proposed assembly’s optical performance, including relevant sun-phantom requirements. Confirm available visor types, dimensions and supply scope with GAOQIAO for the selected model. Do not assume one visor form is always best or that latitude alone determines its depth.
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Frequently Asked Questions
What is sun phantom?
Sun phantom is an apparent signal caused by incident sunlight reflecting through the optical assembly when the light source is off. A suitable visor may reduce unwanted illumination, but performance depends on the complete lens, module, visor and viewing geometry. Confirm the required sun-phantom class or test evidence for the selected assembly rather than assuming a visor eliminates it.
Should I use a tunnel or cowl visor?
Select tunnel or cowl visors using the required viewing field, sun exposure, optical tests and approved signal layout. Confirm the geometry offered for the selected head; traffic direction and appearance alone do not establish the appropriate visor.
How long does a visor last?
Visor durability depends on material grade, UV exposure, temperature and maintenance. Request the selected visor’s material specification and weathering evidence rather than assuming a fixed outdoor service life.
Relevant GAOQIAO products
These public GAOQIAO catalogue pages are related to the guide. Open them for the representative description, then confirm the latest drawing and configuration before ordering.
- Traffic signal controllersWired and solar controllers with 6, 22, 44 and 56 output options.
- LED traffic signal heads200mm, 300mm and 400mm signal heads; confirm the selected model and applicable project requirements.
- Signal polesVertical, signal arm and double-arm poles; confirm suitability for the approved site design.
- Spare parts and accessoriesSpare LED modules, lenses, visors, surge arrestors and anchor bolts.