Why are police car lights one blue and one red?

Police car lights are red and blue, but some countries have only one of these colors, but not green. Red is the primary color in the warm color family and has a warning effect, while blue is the primary color in the cool color family and contrasts with red to attract more attention.

Police lights and sirens are both designed to warn pedestrians to get out of the way so that police can take action. At the same time, they serve as a deterrent to criminals. As for, letting the criminals find out, that's something that can't be helped, however, experienced criminals are not afraid of police cars because police arrests are rarely as fanfare as in TV dramas, and are basically undercover arrests. Unless it's a terrorist incident or other emergency that jeopardizes public **** safety.

The real action is not the use of lights and alarms are caught criminals or action after the end of the lights and alarms, in order to pull faster and safer to go back to the interrogation, in order to prevent the road changes and outside.