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. "That's all we're going for, is for people to know that cyclists have been hit," group member Brad Quartuccio, 22, of Bloomfield, said yesterday. "Some people have lots of respect. The problem is, it only takes one motorist to have no respect."