 Downtown, all the streets and avenues around the National Mall are closed for the fireworks show and the big crowds that you just heard about building. Memorial Bridge is closed. Vehicle traffic for 10th Street and the 12th Street Tunnel are both off limits. The 3rd Street Tunnel and the Southeast Southwest Freeway open. But if you're on I-395 coming in, it's going to be sluggish at the 14th Street Bridge, and you won't be able to take exits 1 or 3.