Our county just picked up a new medic from the Los Angeles area (Mr. Hollywood as we country folks like to call him). We were talking about differences, and he mentioned the emergency lighting was a small thing that he adapting to. Apparently in Cali the color is red for everything (police, fire, EMS), and every emergency vehicle is required to have at least one red "steady burning" light (meaning not flashing).
I thought this was a little weird, but I started paying attention to California reality shows, news, youtube videos, and so on, and I noticed he was right. There's always at least one steady burning red light on the setup.
I have to say that I like the idea of a steady burning light (for tracking purposes). I think they look more professional too. I have since bought a new light bar for my Nissan that is capable of steady burning lights.
I now have wig wag head lights and tail lights, a SuperVisor red/blue setup with two red and blue leds that go steady, Code 3 alternating red grill lights, a 36" amber LED light bar in the back window, and a driver side spotlight that is capable of gelling a solid red (just bought this from an ex CHP officer, really like this product).