Just found this update:

Inaugural Bridges

Yesterday, Transportation leaders announced that Key Bridge will also be closed to car traffic. That means 14th, Memorial, TR and Key are all closed. It does appear that bikes will still be allowed
Instead, these bridges will carry a mixture of motor coaches, shuttle buses and pedestrians, all trying to flock to the central core of D.C. for the ceremony.

but you can expect the sidewalks/MUPs to be filled with pedestrians, so it looks like Commonwealthers will be walking their bikes. You might be able to bike in the road on Memorial or Key, but I'm unsure. There isn't a lot of direction coming out honestly.
Transportation experts have been advising anyone planning to attend the inauguration to either walk or bike to the ceremony if at all possible.



January 07, 2009