To amend the National Highway System Designation Act of 1995 to specify the number and use of vehicle lanes on any replacement of the Woodrow Wilson Memorial Bridge, and for other purposes.

Amends the Woodrow Wilson Memorial Bridge Authority Act of 1995 to provide Federal funding for the removal of the Woodrow Wilson Memorial Bridge after completion of any replacement crossing. Directs that any replacement bridge be open to traffic for operation of no more than 12 vehicle lanes and have two lanes reserved exclusively for one or more of the following: high occupancy vehicles, express buses, or transit. Bars such reserved lanes from being: (1) open to traffic until the systems that such lanes will be a part of in Maryland and Virginia are open to traffic; and (2) used as general purpose lanes unless such use is necessary for incident or accident management or maintenance of traffic during construction or maintenance activities. Prohibits: (1) tolls on any part of the Woodrow Wilson Memorial Bridge Project that is reserved for local traffic; and (2) any replacement crossing from being more than 200 feet wide or from being open to traffic until completion of specified environmental and other mitigation measures. Requires the Secretary of Transportation, if the highest elected local official of a local governmental unit in which any part of the Project shall be located establishes a community oversight committee to provide comments and recommendations regarding Project design and construction, to take any such comments and recommendations into consideration and make appropriate changes. Directs the Secretary to establish the Southern Potomac River Study to: (1) study the feasibility of a new Potomac River crossing south of Interstate Route 495 and north of State Route 301 to accommodate future increased traffic in the metropolitan Washington, D.C. area; (2) select possible alignments for a new river crossing, propose possible crossing options, and identify possible financing mechanisms to acquire the right-of-way and to construct the crossing; and (3) report to the Congress. Requires the Commission to be comprised of representatives appointed from among local elected officials of the jurisdictions in which any part of the Project shall be located and representatives Maryland, Virginia, and the environmental community. Amends Federal transportation law to make available from the Highway Trust Fund such sums as may be necessary to carry out the Project.