 Today's 4th of July festivities are expected to draw hundreds of thousands to the National Mall. WTOP's Grace Newton is there. Security checkpoints will open around 1 p.m. They can be found at Constitution Avenue and Independence Avenue west of 15th Street or by the Jefferson Memorial. Road closures are in effect until tonight when fireworks are complete. And if you want to avoid the hassle altogether, Metro trains and buses will run from 7 a.m. to midnight and are free after 5 p.m.