Ghostbikes, white painted bicycles, are memorials for cyclists who are killed on the street. They shall warn both motorists and cyclists to take care of each other. First ghostbikes were created in St. Louis, Missouri, but the idea is spreading around the world.
Some time ago some people in Vienna started to create ghostbikes too. Sadly, town officials remove them regularly. In the beginning they used notes as Anna described already. I know of some persons who regularly removed this notes from ghostbikes. Recently ghost bikes were removed over night, without having a note sticked to it before.
Alec Hager from IG Fahrrad (a Vienna based bicycle advocacy group) now started a pedition. He demands that the ghost bikes should be left where they were installed.