why red and blue?

Red is both the easiest color to see in the dark and triggers an instinctual brain function response linked to danger.

Blue is a good contrast.

But are all police cars parading around the world using red/blue or just the ones in your area?

Joe(Ours have the occasional burst of clear/white flashing. NYC)Nation

I wish they would change te siren on emergency vehicle cars.
I know they are there to tell us to get out of the way but the schreeching sirens imply total panic, not, calmly indicate and pull over to a safe plac while we pass.

In this part of the world police and emergency vehicles use red and white lights.

Volunteer firemen use blue lights on civilian cars.

All our Victorian (Aust) emergency vehicals went red and blue some years ago. Prior to that it was red only for fire and ambulance, blue only for police and orange for state emergency service (volunteer accident and rescue service).
Road contractors and other non essential like a wide load support vehical use orange now.

The RCMP have the red and blue lights here as well. Don't see many cops arounds these parts though :-)

Well Montana maybe you should be a bad girl. Then you can see some of those pretty red and blue lights. :wink:

Used to be just red. It was discovered that less that totally alert drivers would follow the red in like a heat seeking missile, when the patrol car was stopped. They added blue (and white, I suppose) and the problem went away.

Nah, them are the kind of lights that bug me for some reason, but they only seem to bother me when they're behind me