ghost bike
n.— «They appeared late Monday around Allegheny County, 14 bicycles painted a ghostly white and chained to poles with a cryptic sign: “Cyclist Struck Here.” The roadside memorials are the work of Ghost Bike Pittsburgh, a loosely organized group of bicycle enthusiasts seeking to improve the lot of bicyclists in a sometimes hostile world.…Its goal with the ghost bike project is simple: “to help Pittsburgh become a city where cyclists and motorists can coexist, to the benefit of both groups.”» —“‘Ghost Bikes’ Are Grim Reminders” by Jonathan D. Silver Pittsburgh Post-Gazette (Pennsylvania) May 27, 2004. (source: Double-Tongued Dictionary)