From the SacBee:
They’re spooky. Painted stark white, stem to stern, they’ve appeared seemingly out of nowhere in recent weeks, each chained to a pole on a major Sacramento street.
They are “ghost bikes,” standing silent watch where cyclists have died.
The people responsible for them have kept a low profile. The spray-painted monuments, however, are striking, a form of guerrilla public art that has prompted debate, appreciation, and some unease.