From Purple Line Now:

The MTA just announced that the Record of Decision for the Purple Line has been signed. Formal announcement to follow next week.

As the Maryland Transit Administration’s (MTA) website explains, the Record of Decision is:

The final approval of an Environmental Impact Statement which will be issued by Federal Transit Administration. It is a public document that explains the reasons for a project decision and summarizes any mitigation measures that will be incorporated in the project. Obtaining the ROD is the last step in the NEPA process. After a ROD is received, permits and right-of-way can be acquired.