Ruscha's book projects of the sixties and seventies have come to be recognized as central to photography's development, encouraging both conceptual approaches and interest in analyzing the built landscape. Less well known is his continuing commitment to capturing the various thoroughfares of his adopted home city. Ruscha has used the same automobile-based system to photograph such major boulevards as Wilshire, Hollywood, and Sepulveda, and, more recently, "suites" of smaller roads in Chinatown, Silver Lake, and other neighborhoods. At present, the Streets of Los Angeles project numbers more than forty separate shoots and well over a million exposures.