Abstract: An interior lens is provided for a light bar mountable onto the roof of a vehicle. The interior lens has a plurality of fluted lenses or lens segments forming a ribbon shaped to receive illumination prior to exiting the light bar outer dome. The fluted lenses extend vertically parallel to each other and are each shaped to increase the horizontal viewing angle of light from the light bar. The ribbon of fluted lenses may continuously extend within the light bar around the optical assembly to improve performance of light projected from different sides of the light bar, thereby providing an improved optical assembly for a light bar.