Selective Yellow Lens Covers – the Trifecta of Conspicuity!

The Trifecta of Conspicuity!

Color, in addition to light and contrast, are the primary components of conspicuity. Clearwater Lights has engineered removable, protective, “selective yellow” lens covers specifically for use with our lights so that you can have all three. We call the powerful combination of Clearwater Lights and our proprietary selective yellow covers the “Trifecta of Conspicuity!”


The well-known Hurt report, as well as other studies (mostly conducted by the National Highway Transportation Safety Association),  conclude that the failure of motorists to recognize motorcycles in traffic as the predominant cause of motorcycle collisions – “I didn’t see him!” This is because the eyes of car drivers are trained to look for car-sized obstacles on the road, indicated by a large windshield, a wide bumper, or two headlights. The HURT report also concludes that the use of hi-vis yellow in motorcycling gear reduces accidents by around 37% (although it bears repeating that the color in our selective yellow lens covers is additive and based on a light-emitting source, while the color of your protective motorcycle gear is subtractive and based on pigments.) And, a 1980 study entitled “Human Factors in Transport Research” found that “The most important issue with [gear] is the contrast a motorcyclist makes with his background.” A more recent Dutch study concluded that “…contrast with the environment is a major factor to improve conspicuity.”

By adding Clearwater Lights, your motorcycle will appear larger and wider because they draw attention to areas other than the singular headlight. When placed appropriately, auxiliary lights also create what is known as the “triangle of conspicuity” which allows a motorist to differentiate between a motorcycle and a car with a headlight out. How you may ask? As the triangle gets larger, anybody can judge that the triangle is getting closer. No matter what grade you received in your geometry and trigonometry classes, your brain automatically performs thousands of geometric and trigonometric calculations per second when it is viewing an approaching motorcycle with a triangular array of lights. Cut that down to one single headlight, and your brain has much less information to process. Because of this, adding a set of auxiliary lights to a motorcycle increases motorists’ ability to judge a motorcyclist’s distance by approximately 10%, and speed by approximately 20%, as well as their direction. This is particularly useful in preventing the most common motorcycle crash situation – the oncoming left turn.


We see color based on the distance between the peaks of waves of energy (wavelengths) of the spectrum generated by light-emitting sources, and how the rods and cones in our eyes are stimulated by these wavelengths. For example, our eyes perceive wavelengths of light between 620 and 750 nanometers (nm) as red, 590 to 620 nm as orange, 570-590 nm as yellow, and 495 to 570 nm as green.

When multiple wavelengths are generated by a light source, they merge together to create colors – these are known as additive colors. The sun produces a spectrum of light that we can see, as well as longer and shorter ones that we can’t see. When all these wavelengths occur together, the light we see is white. The light produced from various emitting devices can be filtered so that only certain wavelengths pass through. If you live in California or one of the other areas hit hard by wildfires this summer, you know that the sun and sunlight hitting your floor appear reddish-orange. That’s because of the smoke from the wildfire filters out shorter wavelengths, allowing only longer red/orange wavelengths to filter through.

In contrast, printed media uses pigments to create color. Pigments can be blended together to create additional colors. When you mix a lot of pigments together, you get a color close to black. When we see an object, we see the pigments corresponding to the wavelength of light for the color of that object. For example, when light hits your red Aerostich suit, light corresponding to the color red is reemitted back to our eyes, and the other wavelengths are absorbed (and dissipated as heat). To create high-visibility colors (or the neon clothing popular in the 80s), additional pigments are added that reflect short, invisible wavelengths of ultraviolet light, making items appear like they are glowing.

So, what’s the deal with selective yellow? Scientists have found that the human eye is most sensitive to light at a wavelength of 555 nanometers, which corresponds to the bright shade of yellow-green that we’re used to seeing in industrial and motorcycle safety gear. This is why we designed protective lens covers specifically for use with our lights that filter out all wavelengths of light except for 555 nm.


Our proprietary selective yellow lens covers create light that stands out against almost every other color in nature – even the glint of sunlight reflecting off a vehicle that often mimics headlights. This ensures that you are the most visible thing in the landscape, even at great distances.

Remember the color wheel from your grade school art class? Yellow is opposite blue in that color wheel, so our selective yellow lens covers stand out particularly well against the blue daytime sky. We like to say they are “anti-blue.” They are even more effective at dawn and dusk when red-violet hues are more dominant in the sky because the 555 nm yellow-green wavelength is directly opposite of these colors on the color wheel.

Why you NEED our selective yellow lens covers for YOUR Clearwater Lights!

The combination of Clearwater Lights and our proprietary selective yellow lens covers offers a powerful combination of conspicuity that allows you to get noticed. By combining 1) added light, 2) a triangle of conspicuity, and 3) the most visible color in the spectrum that provides a stark contrast to all other colors in your environment, you are employing all three measures statistically shown to aid in conspicuity necessary for incident prevention. We like to call this combination the “Trifecta of Conspicuity!”

The best part is that our lights with our proprietary selective lens covers are weather-proof and not rider-specific. We are certainly not suggesting that you ditch your hi-vis gear; we want you to be as visible as you can, and as our owner likes to say, “If that means you need to wear a lime green monkey suit while riding, DO IT!” But think about it – gear is expensive, and you might need both a winter and summer jacket in hi-vis yellow to stay visible year-round. You’d also want hi-vis yellow rain gear to keep you visible in poor weather conditions. And of course, some of us may have uh, “outgrown” the gear we invested so much in. So, there’s a chance we may need to ride without our hi-vis gear. Because adding selective yellow lens covers to the Clearwater Lights you have permanently installed on your bike, they allow you to maintain some hi-vis yellow throughout all weather conditions regardless of your gear. You don’t have to buy new ones after eating one too many cookies at the holidays, and they don’t require special cleaning methods. Best yet, they are available as an inexpensive add-on option with your order* of any set of Clearwater Lights. Stand out against your environment and grab yours today!


*If you purchased and installed Clearwater Lights before the selective yellow lens covers were available, please contact us directly to discuss how we can help!

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