This page: https://www.straightdope.com/21341613/who-decided-red-means-stop-and-green-means-go https://www.straightdope.com/21341613/who-decided-red-means-...

This page: https://www.straightdope.com/21341613/who-decided-red-means-stop-and-green-means-go https://www.straightdope.com/21341613/who-decided-red-means-... Argues that using "red" for danger dates so far back into history as to be a signal of danger for essentially all of history. The rest of the page argues that the colors for traffic lights was derived from railroad signalling, and that railroad signalling originally used red for stop, green for caution, and white for go, until a major crash resulted in a change to red for stop, yellow for caution, and green for go. As for electronics devices, those designing them probably just used what was common (traffic light colors) for their color choices without giving anything much thought. Also remember that the first visible light LED was also red, which likely further contributed to choosing "traffic light colors" once green and amber LED's became available.