Why red why green?

Question

Pub regular, Old Sid says he can remember when traffic lights were red and green but how far back in history has red signalled danger?

Answer 1

Red has always signified "danger". Poisonous berries, blood, hot coals etc.
Green is something to go for (and I'm not just speaking metaphorically). Alot of vegetables are green. Where green grass can grow, signifies where the water is etc.

Answer 2

Red and green are primary colors, so they are easy to produce. Red signaling danger came from the color of fire, since early signals were based on fire as the light source.

Green conjures up the pastoral spring views of safety as the seasons change from the harshnest of winter.

Here's some traffic light history that is fun:

Even during the horse and buggy days, traffic in big cities was often heavy. Police officers had to be stationed full time directing traffic at busy intersections.

The world’s first traffic light came into being before the automobile was in use, and traffic consisted only of pedestrians, buggies, and wagons. Installed at an intersection in London in 1868, it was a revolving lantern with red and green signals. Red meant "stop" and green meant "caution." The lantern, illuminated by gas, was turned by means of a lever at its base so that the appropriate light faced traffic. On January 2, 1869, this crude traffic light exploded, injuring the policeman who was operating it.
With the coming of automobiles, the situation got even worse. Police Officer William L. Potts of Detroit, Michigan, decided to do something about the problem. What he had in mind was figuring out a way to adapt railroad signals for street use. The railroads were already utilizing automatic controls. But railroad traffic traveled along parallel lines. Street traffic traveled at right angles. Potts used red, amber, and green railroad lights and about thirty-seven dollars worth of wire and electrical controls to make the world’s first 4-way three color traffic light. It was installed in 1920 on the corner of Woodward and Michigan Avenues in Detroit. Within a year, Detroit had installed a total of fifteen of the new automatic lights.
At about the same time, Garrett Morgan of the United States realized the need to control the flow of traffic. A gifted inventor and reportedly the first African American to own an automobile in Cleveland, Ohio, he invented the electric automatic traffic light. Though it looked more like the semaphore signals you see at train crossings today.

Many others had obtained US Patents for Traffic Signals, some as early as 1918. But Morgan's Patent was purchased by General Electric Corporation and provided the concept on which GE's four-way traffic lights are based.

Answer 3

Eh, Green is NOT a primary colour. Red Blue and Yellow are. Green is made up of Blue and Yellow. Basic primary education there!

Then Why does a TV Have RGB?

Answer 4

Eh, Green is NOT a primary colour. Red Blue and Yellow are. Green is made up of Blue and Yellow. Basic primary education there!

Answer 5

I think all the way back to when people saw blood being spilled when wild animals or other men attacked..

Answer 6

your all wrong , although all light travels at the same speed
Red is quicker to the eye and blood has got bugger all to do with it

Answer 7

Red is dead. Green is clean.

Answer 8

Yeah s/hes right

Answer 9

red is fire, hot
green is grass