Republik of MD is red/blue. My Interceptor SUV runs Vertex mini lights throughout the exterior that are very bright but not so much that they are blinding for traffic.

Here in south Florida police have used blue and white for at least 2 decades, fire has used red and white, and met has used orange and white.

In Arkansas, law enforcement uses blue lights. They have to use blue, by law. Some agencies use red alongside blue, but most don't.

Red is required for fire trucks and ambulances.