Never heard of it. Have to remember the US mainland was never really in danger of serious attack. I think there may have been blackouts of major cities early on, probably mostly on the West Coast out of exaggerated fears of Japanese attack - they had after all successfully attacked Hawaii. But the closest thing to an attack on the mainland was attacks by German U-boats on shipping off the coast.
My impression is that the biggest role of the bicycle in the US war effort was a few people may have taken up cycling due to wartime rationing of gasoline. May also have been a few mobile units that used bicycles in the fields, but I think this was more widespread in the armies of the other nations invloved than in the US military.
Big Spring, TX, USa
> From: Daniel Dahlquist <email@example.com>
\r?\n> Subject: [CR] Civil Defense Bicyclists???
\r?\n> To: firstname.lastname@example.org
\r?\n> Date: Tuesday, March 24, 2009, 1:41 PM
\r?\n> Dear Group, No doubt many on the list are familiar with the
\r?\n> British couriers
\r?\n> and civil defense bicyclists with their black out lamps
\r?\n> during the Blitz of
\r?\n> World War II...Does anyone know if we had a counterpart
\r?\n> here in the states
\r?\n> during WW II? I know we had a corps of Civil Defense folks
\r?\n> with helmets,
\r?\n> uniforms, etc...but did any of these individuals ride
\r?\n> Daniel Dahlquist
\r?\n> Galena, Illinois