An illumination device includes: an optical waveguide having a first lateral surface for emitting light and a second lateral surface for receiving light; a scattering cap secured to the first lateral surface of and extending substantially the length of the waveguide; and a light source (e.g., a plurality of LEDs spaced a predetermined distance from one another) positioned adjacent to the light-receiving surface of the waveguide. Light entering the waveguide is efficiently transmitted to the scattering cap and is then preferentially scattered so as to exit with a broad elongated light intensity distribution pattern being formed along a lateral surface of the scattering cap.