This report documents the actions taken by transportation agencies in response to the earthquake in Northridge, California on January 17, 1994, and is part of a larger effort to examine the impacts of catastrophic events on transportation system facilities and services. The findings documented in this report are a result of a detailed literature search on Northridge lessons learned. As part of a larger effort, four case studies will be produced: New York City, September 11, 2001 Washington, D.C., September 11, 2001 Baltimore, Maryland, rail tunnel fire, July 18, 2001 Northridge, California, earthquake, January 17, 1994."