The housing protects the LEDs, driver and lens from UV, rain, salt and impact. Polycarbonate, die-cast aluminum and engineered PC have different strengths, and the right choice depends on climate, road environment and expected lifespan.
Housing material comparison
| Property | Polycarbonate (PC) | Die-cast aluminum | Engineered PC composite |
|---|---|---|---|
| Weight | Confirm the documented mass of the selected 300mm signal head; 1-3 kg is not a universal weight range. | Assembly mass: obtain the actual weight of the 300mm head configuration | Assembly mass: verify the selected 300mm head and supplied accessories |
| UV stability | Verify UV-ageing evidence for the selected material grade | Excellent | Verify UV-ageing evidence for the selected material grade |
| Impact resistance | Verify impact resistance for the selected material and enclosure | Medium (can dent) | High |
| Heat dissipation | Low | High | Medium |
| Corrosion resistance | Excellent | Requires coating | Excellent |
| Cost | Medium | Higher | Lower |
| Typical lifespan | 10-15 years | 15-25 years | 8-12 years |
| Common use | Urban, pedestrian | Highway, industrial | Budget projects |
1. Why the housing material matters
The traffic light housing is exposed to the worst weather the road can produce: UV radiation that yellows plastic, rain that finds every seal, road salt that corrodes metal, and impact from stones and debris. A poor housing choice shortens the life of the LEDs and driver, even if the electronics themselves are well designed.
Four properties drive the material choice: UV stability (does the colour fade under sunlight?), impact resistance (does it survive stone chips and vandalism?), thermal conductivity (does it pull heat away from the LEDs?), and corrosion resistance (does it survive salt, pollution, acid rain?). The right answer depends on climate, road environment and expected service life.
2. Polycarbonate housings
Polycarbonate (PC) is used for moulded traffic-signal housings. For the selected grade, check impact strength, UV stabilisation, colour-ageing evidence and resistance to the site’s chemicals and weather. A UV-stabilised resin does not by itself guarantee a fixed period of unchanged colour.
Polycarbonate can support lightweight, moulded housing and accessory designs. For the selected grade and assembly, check impact-test results, UV ageing, chemical resistance, surface durability and mounting loads. Its thermal conductivity is lower than aluminium’s, but LED temperature depends on the complete heat path, driver losses and ambient conditions. For 200mm and 300mm urban signal heads, compare the approved enclosure designs rather than selecting PC by diameter alone; impact resistance does not mean that breakage is impossible.
3. Die-cast aluminum housings
Die-cast aluminium may be considered for highways, industrial zones and demanding environments. Evaluate the specific alloy, coating, mechanical design and thermal path of the complete signal head. A conductive housing only helps LED heat dissipation when the assembly provides a suitable path from the heat source. Confirm UV, impact and corrosion performance with model-specific evidence; do not infer junction temperature or service life from the housing material alone.
Aluminium housing can provide a useful heat-conduction path when the thermal design connects the light source and driver appropriately. Check the actual assembly mass, mounting loads, impact evidence, coating and corrosion protection, especially in salt-air exposure. Cost, repairability and service life depend on the design and maintenance conditions. For 400mm signal heads or hot, coastal and vandalism-prone sites, compare the documented performance of the available enclosures rather than assuming that aluminium always provides the best result.
4. Engineered PC composite housings
For an enclosure described as engineered PC composite, request the exact resin grade and reinforcement specification. If it is glass-fibre-reinforced polycarbonate, compare its actual mass, impact and weathering evidence, dimensional behaviour and quotation with the alternative assemblies. The label alone does not establish lower cost or an intermediate level of performance.
Advantages: lower cost than aluminium or pure PC; reasonable heat dissipation through the glass-fibre filler; good impact resistance; and naturally corrosion-proof. Limitations: heavier than pure PC; less refined finish than machined aluminium; not as widely accepted for premium projects; and surface quality varies by manufacturer. Engineered PC composite suits budget tenders, large-volume orders, and projects where the housing is replaced rather than repaired at end of life.
5. Climate and site considerations
Climate and site conditions affect housing selection. At coastal sites, compare the corrosion resistance of the proposed aluminium alloy and coating with the proposed polycarbonate grade. For desert sites, request evidence of UV and temperature suitability for the specific material formulation. At cold sites, assess temperature, impact and road-salt exposure; at tropical sites, consider humidity, seals and biological growth. For industrial sites, identify the actual chemicals and check material and coating compatibility. Do not infer a corrosion time, repainting interval or chemical-resistance ranking from the material name alone.
6. Spare parts and replacement housings
Whichever housing material is selected, plan compatible replacement modules and spare enclosure parts. Inspect for yellowing, cracks, corrosion and seal deterioration, and use the actual failure history rather than assuming one universal end-of-life cause. Confirm replacement-module fit and electrical compatibility; identify required seals, lenses, visors and brackets. Set spare quantities from the installed population, failure risk, supply lead time and maintenance policy instead of a fixed percentage.
7. How to specify housing material in an RFQ
State the housing material explicitly in the quotation request, including the required grade, UV stabilisation, colour and finish. Distinguish polycarbonate from any proposed composite and require approval for substitutions. For aluminium, specify the alloy and coating requirements; specify mounting hardware separately. If UV performance or a warranty period is required, state the requested evidence and obtain written confirmation of the offered scope and conditions. Do not assume a material name includes a particular service life or warranty.
Frequently asked questions
Which is better: polycarbonate or aluminum traffic light housing?
Select the housing for the site using actual mass, thermal design, impact and weathering evidence, coating, maintenance and quoted cost. For 200-300mm urban heads or 400mm heads at highway, coastal or hot sites, diameter and location alone do not determine the best material. Compare the approved complete assemblies.
Do aluminum traffic light housings need a coating?
Assess corrosion protection separately for the aluminum housing and steel mounting hardware. Coastal salt, road salts, dissimilar-metal contact and coating damage can affect performance. Specify compatible surface preparation and coating systems for each substrate and confirm inspection and repair requirements; no single finish guarantees the longest life in every environment.
What is engineered PC composite?
For an enclosure described as engineered PC composite, request the exact resin grade and reinforcement specification. If it is glass-fibre-reinforced polycarbonate, compare its actual mass, impact and weathering evidence, dimensional behaviour and quotation with the alternative assemblies. The label alone does not establish lower cost or an intermediate level of performance.
How long does a polycarbonate traffic light housing last?
Polycarbonate housing durability depends on resin formulation, UV stabilisation, exposure and maintenance. Do not assign a fixed service life from climate alone. Inspect yellowing, haze, cracking and loss of sealing or mechanical integrity against the manufacturer’s acceptance criteria; appearance changes do not all have the same functional significance.
Can I replace the housing without replacing the LED module?
Whether components can be transferred to a new housing depends on the exact models and their condition. Confirm module, driver, wiring, sealing and mounting compatibility with the manufacturer before ordering. Request the approved replacement procedure and identify parts that must be renewed. Do not assume every GAOQIAO head allows the same module-level replacement or that an enclosure change preserves all performance ratings.
Are polycarbonate housings vandal-proof?
Evaluate the selected PC enclosure’s impact-test evidence rather than assuming it cannot shatter. For vandalism-prone sites, assess the complete wall design, fixings and protection measures. Confirm any anti-graffiti coating’s compatibility with the substrate and approved cleaning method.
Which material is best for hot climates?
Aluminum and UV-stabilised polycarbonate housings have different thermal and mechanical properties. Suitability depends on the complete thermal design, solar exposure, ambient temperature range and documented performance of the selected model. Confirm operating limits and LED thermal management rather than choosing a housing solely from a generic temperature threshold.
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.
- 300 mm (12 inch) LED traffic lightsPolycarbonate and aluminum housings for standard urban intersections.
- 400 mm (16 inch) LED traffic lightsHeavy-duty aluminum housings for highway and high-speed approaches.
- 200 mm (8 inch) LED traffic lightsCompact polycarbonate housings for pedestrian and side-road applications.
- Spare parts and accessoriesLenses, visors, door seals, mounting brackets and replacement modules.