From a press release:
Travelers should expect major lane closures on the I-395 general purpose lanes beginning the weekend of July 20-22, and continuing for at least six consecutive weekends, depending on weather. The weekend closures, which will occur from Friday nights until Monday mornings, are needed for crews to safely rehabilitate multiple bridges along I-395 between the Springfield Interchange and the Washington, D.C. line. Motorists are encouraged to use alternate routes. If travel in this area is unavoidable, drivers should use caution and plan extra travel time.
