I always find this subject interesting. Nebraska funeral homes don't use purple lights since our funeral escort vehicles (coach, limo, seperate vehicle) under state law are considered authorized emergency vehicles and can use red lights. The funeral home I work at I just replaced our old Federal Fireballs with LEDs.
Nebraska State Statute,
60-6,231. Flashing or rotating lights; authorized emergency vehicles; colors permitted.
A flashing or rotating red light or red and white light shall be displayed on any authorized emergency vehicle whenever operated in this state. A blue light may also be displayed with such flashing or rotating red light or red and white light. For purposes of this section, an authorized emergency vehicle shall include funeral escort vehicles.