why the color red is used as alert alarm like in traffic lights?

Question

i mean what is the sientific explanation of that?

Answer 1

May be since blood is red in colour, and flow of blood alerts a person to draw attention towards the need for care or caution, people chose it as a natural choice.

Answer 2

All light is dispersed within the atmosphere by all the gasses bust mostly by water vapor and dust. The dispersion at the blue end of the spectrum is greatest and so under adverse conditions red is most likely to be seen from a distance.
Peoples perception of color changes as they age. Their eyes become less sensitive to blue so reds and yellows are good colors for warnings.
There is also the matter of how human beings feel about colors. In general a nice blue sky conveys a general feeling of things being OK. Green is nice and tranquil, presumably because green fields and forest indicate a good food supply and safety.
Red certainly gets our attention, if you want to sell something put it in a red packet. This may be because it is the color of blood and fire and associated with danger.

Answer 3

This question has been asked and answered at least 5 times in the past week. Some of the answers were very good... perhaps you can look them up.

Answer 4

It's the color that can be seen from the greatest distance.

Answer 5

the color red has a higher wavelenght frequency compared to other colors and therefore, our eyes would detect this color more often than lower wave frequency colors.

Answer 6

Most people that see red see fire. Like hot. Stop!!! I tried.
Take care.

Answer 7

it gets your attention more than any other color and can be seen the easiest from a distance.