Why has "red alert" always been the worst level?

Question

Where did the color scheme come from on the level of alerts?

Answer 1

Chances are it falls in with the whole association of red with danger or negative things e.g. traffic lights and warnings etc. It is generally accepted that red is linked to these things, so red alert is linked to the most danger. If you also think of less serious as yellow alert, it also links to the traffic lights idea. Probably comes from nature, red and yellow are generally associated with danger (wasps / bees, red berries etc)

Answer 2

Star Trek.