A Ghost Bike is a white-painted bike that is placed at a location where a cyclist has been hit. According to an old post on bello velo, this photo depicts the first Ghost Bike, memorializing an accident on Holly Hills Boulevard in St. Louis, Missouri. It was created by Patrick Van Der Tuin who saw a cyclist hit by a car. A few days later, he and his friends locked several bikes at locations where he knew cars had collided with cyclists. Since then, the meme has spread nationwide. GhostBike.org is a clearinghouse of Ghost Bike installations and photos of the sites. Link to GhostBike.org, Link to bello velo (via CT2)
David Pescovitz is Boing Boing's co-editor/managing partner. He's also a research director at Institute for the Future. On Instagram, he's @pesco.