After the 2001 terrorist attacks , the Bureau of Reclamation analyzed potential targets for vulnerability and measures that could be taken to eliminate or reduce possible threats . With 500,000 residents in the vicinity of the Folsom Dam , the possibility of an attack on the dam was great enough concern for Bureau officials to close Folsom Dam Road . The road over the dam had been a major artery for the city of Folsom . With its closure , traffic became severely congested during rush hour . The impact was so great that residents and city officials petitioned the federal government to reconsider the road closure , which the government initially considered . Continued security concerns prevented them from re-opening the road and a new bridge , named Folsom Lake Crossing , was constructed and opened on March 28 , 2009
terrorist attacks
September 11 attacks
Folsom Dam