School bus stop arm and drive unit therefor

1. A stop arm for a school bus comprising:

a stop sign comprising a sign assembly including:

two stop insignia displayed on opposite sides of said stop sign assembly, each stop insignia comprising a respective written stop message on a backdrop surrounding said respective written stop message, and

at least one internal illumination device installed within said sign assembly and configured to illuminate the respective written stop message and the respective backdrop of each stop insignia upon activation of said at least one internal illumination device, wherein the illuminated area of the backdrop of each stop insignia has the shape of an octagon or the shape of an octagon having on or more cutouts; and

a drive unit mountable to a side of the school bus for selectively moving the stop sign between a deployed position and a retracted position,

wherein said internal illumination device comprises a diffusion panel underlying both the respective written stop message and the respective backdrop of one or both of said stop insignias, and a set of one or more light sources positioned to illuminate said light diffusion panel upon activation of said set of one or more light sources.

2. The stop arm of claim 1 , wherein said diffusion panel is an edge-lit panel with the set of one or more light sources residing at or proximate an outer perimeter of said first edge-lit panel to cast light inwardly toward a center thereof.

3. The stop arm of claim 1 , wherein one or more of said set of one or more light sources are concealed behind a frame of the sign assembly.

4. A stop arm for a school bus comprising:

a stop sign comprising a sign assembly including:

two stop insignia displayed on opposite sides of said stop sign assembly, each stop insignia comprising a respective written stop message on a backdrop surrounding said respective written stop message, and

at least one internal illumination device installed within said sign assembly and configured to illuminate the respective written stop message and the respective backdrop of each stop insignia upon activation of said at least one internal illumination device, wherein the illuminated area of the backdrop of each stop insignia has the shape of an octagon or the shape of an octagon having on or more cutouts; and

a drive unit mountable to a side of the school bus for selectively moving the stop sign between a deployed position and a retracted position,

wherein each stop insignia further comprises a perimeter border surrounding the respective backdrop and overlying one or more light sources of the at least one internal illumination devices, said perimeter border having greater opacity than said respective backdrop to at least partially reduce a direct visibility of said one or more light sources.

5. The stop arm of claim 1 , wherein said sign assembly further includes a reflector disposed behind said light diffusion panel.

6. The stop arm of claim 1 , wherein each stop insignia is displayed on a respective lens mounted over the at least one internal illumination device.

7. The stop arm of claim 6 , wherein the lettering of each stop insignia is printed on said respective lens.

8. The stop arm of claim 6 , wherein the backdrop of each stop insignia is printed on said respective lens.

9. A stop arm for a school bus comprising:

a stop sign comprising a sign assembly including:

two stop insignia displayed on opposite sides of said stop sign assembly, each stop insignia comprising a respective written stop message on a backdrop surrounding said respective written stop message, and

at least one internal illumination device installed within said sign assembly and configured to illuminate the respective written stop message and the respective backdrop of each stop insignia upon activation of said at least one internal illumination device, wherein the illuminated area of the backdrop of each stop insignia has the shape of an octagon or the shape of an octagon having on or more cutouts; and

a drive unit mountable to a side of the school bus for selectively moving the stop sign between a deployed position and a retracted position,

wherein each stop insignia is displayed on a respective lens mounted over the at least one internal illumination device, and

wherein a respective film is adhered to each respective lens and embodies at least one or both of the respective written stop message and the respective backdrop of the stop insignia.

10. The stop arm of claim 9 , wherein said respective film has a retro-reflective surface.

11. A stop arm for a school bus comprising:

a stop sign comprising a sign assembly including:

two stop insignia displayed on opposite sides of said stop sign assembly, each stop insignia comprising a respective written stop message on a backdrop surrounding said respective written stop message, and

at least one internal illumination device installed within said sign assembly and configured to illuminate the respective written stop message and the respective backdrop of each stop insignia upon activation of said at least one internal illumination device, wherein the illuminated area of the backdrop of each stop insignia has the shape of an octagon or the shape of an octagon having on or more cutouts; and

a drive unit mountable to a side of the school bus for selectively moving the stop sign between a deployed position and a retracted position,

wherein each stop insignia is displayed on a respective lens mounted over the at least one internal illumination device,

wherein each lens comprises a pair of cutouts reaching inwardly from an outer perimeter edge of said lens at opposing top and bottom segments of said outer perimeter edge, and

wherein the sign assembly further includes a pair of flashers occupying said cutouts.

12. The stop arm of claim 1 , wherein the sign assembly further includes a pair of flashers occupying cutouts in the backdrop.

13. A stop arm for a school bus comprising:

a stop sign comprising a sign assembly including:

two stop insignia displayed on opposite sides of said stop sign assembly, each stop insignia comprising a respective written stop message on a backdrop surrounding said respective written stop message, and

at least one internal illumination device installed within said sign assembly and configured to illuminate the respective written stop message and the respective backdrop of each stop insignia upon activation of said at least one internal illumination device, wherein the illuminated area of the backdrop of each stop insignia has the shape of an octagon or the shape of an octagon having on or more cutouts; and

a drive unit mountable to a side of the school bus for selectively moving the stop sign between a deployed position and a retracted position,

wherein the drive unit comprises a controller for controlling activation and illumination of the at least one internal illumination device, and

wherein the controller is configured to reduce a brightness of the at least one internal illumination device during movement of the sign between the deployed and retracted positions.

14. The stop arm of claim 13 , wherein the controller is further configured to increase the brightness of the at least one internal illumination device to a desired brightness once the stop sign has reached the deployed position.

15. The stop arm of claim 1 , wherein the sign assembly further includes a frame that completely surrounds and encloses a perimeter of the at least one stop insignia.

16. The stop arm of claim 1 , wherein one or both of said respective written stop message and said respective backdrop of the stop insignia comprise a retro-reflective material.