News Advisory for Immediate Release August 21, 2003 12th St. Underpass Closed Friday Night (Washington, DC) Weather permitting, the District Department of Transportation will close the 12th Street underpass that takes northbound traffic the Mall from 7 pm Friday to 5 am Saturday morning. Traffic from the Southwest Expressway and northbound 395 (14th Street Bridge) will be diverted to 14th Street. The closure is for repair of Jefferson Drive on the Mall over 12th Street.