Jersey uses Blue for "regular" vollies. Chiefs and Asst Chiefs are also able to use red. We have to get a permit through the NJ Motor Vehicle Commission though. Part of the app is getting it signed by our chief as we as the mayor of the town to verify that we are infact vollys...
In Kansas we can use red, blue, white(to the front), Amber(to the rear); must be seen 360 degrees around the vehicle. Siren must be audible 500ft. In some counties it is left up to the Co. Commisioners, the sheriff, or Emergency Managment to sign off permission. Then the permit must be registered to the vehicle that has the equipment, and in said vehicle. If asked for.
In Alaska we are allowed to use Blue Lights, but it is left to our departments discretion. At mine, Nikiski Fire, we must be what is known as Stand-by EMS or Stand-by Fire. This means you've gone through a check off that says you are proficient in all your alloted skills and that you know the entire inventory of certain compartments and kits in the rigs. After you get Stand-by status you must get written permission from the chief for the Blue Light.
Man Just Be smart about it once you get close to the scene turn it off and use it wisely if they dont know they can't say jack shit but if you do something that hurts someone else then you will be in a load of trouble used your instinct weigh out the risk