The yellow border on traffic lights is called a reflective backplate.
These backplates serve an important function in improving the visibility of traffic signals, particularly in challenging visual environments. Here's a more detailed breakdown:
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Purpose: Reflective backplates are designed to make traffic lights more conspicuous to drivers.
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Improved Visibility: They achieve this by providing a contrasting background around the lights, which helps them stand out against cluttered or bright backgrounds. This is especially beneficial during:
- Morning and Evening Hours: When the sun is low on the horizon, it can create glare that makes it difficult to see traffic lights. Backplates help to mitigate this effect.
- Areas with Visual Clutter: In urban areas with numerous signs, buildings, and other visual distractions, backplates ensure that traffic lights remain easily noticeable.
- Unusual Light Spacing: Backplates can also help to visually group traffic lights together when they are spaced unusually far apart, making them easier to interpret.
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How they Work: The backplates are typically made of a reflective material that reflects light back towards the driver's eyes, further enhancing their visibility.
In summary, the yellow, or sometimes other colored, border on traffic lights isn't just a design element; it's a safety feature designed to improve visibility and ensure drivers can easily see and react to traffic signals, regardless of environmental conditions or visual distractions.
