People who are blind in red and green can't drive. Why can't some people tell colors apart?

In fact, the reason is very simple. The green light in a standard traffic light contains white light, while the ability of red-green color blindness to distinguish color saturation and brightness is higher than that of normal color vision. When these two factors are combined, red-green color blindness will not have any difficulty in distinguishing traffic lights. This is also the reason why driver's licenses in many countries do not limit red and green color blindness. Red-green blindness accounts for 5% of the population. If such a large proportion of people can't recognize the traffic lights, it will be a problem to cross the road. Isn't the setting of traffic lights a joke?

Judging from the answer to this question, many people have a great misunderstanding about color blindness, and some interviewees even think that color blindness is color blindness. In fact, color blindness is very rare, and it is legendary, much less than natural blindness.

Most color blindness is actually red-green color blindness, accounting for 5% of the population. The reason why the proportion is so high is that there is a certain proportion of red and green color blindness in the early human life needs groups. Although early humans were mainly active during the day, it was inevitable that some activities had to be carried out at night. The night vision ability of red-green color blindness is much higher than that of normal color vision, which can improve the survival ability of the whole ethnic group. Of course, the efficiency of red-green color blindness in picking red fruits is low, but early human groups also relied on cooperation.

In addition, the phenomenon of color blindness was not discovered in the long river of human history until the last hundred years, which shows that the influence on daily life is much lower than many people think-maybe some people can see the surrounding scenery clearly when walking at night, and people will only doubt that this person's eyesight is better; Maybe some people are not so efficient in picking some fruits (not to say that they can't tell the difference, if they can't tell the difference, the phenomenon of color blindness would have been discovered long ago), but it may just be that the flexibility of their hands is not so high. In addition, there is no other influence, so for thousands of years, no one has found this phenomenon.

Red has a long wavelength, so it can be seen clearly in a far place with high recognition. As the contrast color of red, green has high contrast and clear meaning. As a transition light between red light and green light, yellow is said to have been invented by Hu Ruding, a Chinese studying in the United States, to remind people that the signal light is about to switch, and pedestrians or vehicles in different driving directions should be prepared accordingly.