If I remember correctly from the beta version I looked at several months ago (they sent links to lots of people) these were not so much routes that are designated for bicyclists, but roads that could not be easily accessed with Google's truck-mounted cameras. Instead, they mounted cameras on tricycles and had people ride all the nooks and crannies taking panoramic pictures. They also advertised for people to ride around for them at one point, and I do not recall any kind of prerequisite such as knowing the roads that are suitable and open for bicycling.