Whats the meaning of red and blue lights on police vehicles?

Main reason is colorblindness alert,then is what the law enforcement has adopted from the beginning of time,on vehicles:blue stands for law enforcement,red is for emergency vehicles (including police cruisers),yellow caution...and green is for security officers. Blue/red police. Red/yellow fire/ems.Green/amber for Security officers. As all traffic lights are designed to be useful on both normal eye and color blind humans so are the emergency vehicles lights.