The Color of Solar Road Studs

Now we can often see road studs on the road. The function of road stud is to send out strong guiding light when the light is dim (such as rainy day, foggy day, night) to warn the driver of road changes ahead.
There are five common solar road stud colors: red, yellow, blue, green and white. The light is emitted through the bilateral LED lights or the unilateral LED lights. But what's the effect of different colors of road studs? What's the difference? Is the road stud a random color?

As we know, visible light is a form of electromagnetic wave, which can be perceived by human eyes. For the same energy, the longer the wavelength is, the less easy it is to scatter and the farther it propagates. The light emitted by the solar road stud is visible light. The average person's eye can sense the wavelength of electromagnetic wave between 400 ~ 760 nm, and the wavelength of light with different frequencies is also different. The wavelength range of red light is 760 ~ 622 nm; the wavelength range of yellow light is 597 ~ 577 nm; the wavelength range of green light is 577 ~ 492 nm. It can be seen that the light color of road stud is not optional.

First of all, I think there should be a unified color for the common colors of solar road studs to avoid the situation that the road is too colorful and disturbs the driver's sight. Secondly, these colors are easier to notice. Only in this way can the solar road stud guide the line of sight, illuminate the road and identify the edge of the road.
There are many traffic safety facilities on the road now, and the road stud is a very effective lighting tool. What colors would you like the road studs to have?