Seattle's Sound Transit board of directors unanimously approved an amendment to the agency's 2012 budget to provide $24.3 million in additional funding for establishing a shovel-ready plan to extend light rail.

The plan gives the agency a green light to immediately move forward with a conceptual engineering study, environmental review process and record of decision on a route not only to S. 272nd Street, which voters approved in the Sound Transit 2 ballot measure in 2008, but all the way to the Federal Way Transit Center. Determining a specific route and more accurate cost estimates will support efforts to identify financing for constructing the line south of the Kent/Des Moines area.

Planning for the extension is slated to begin with an alternatives analysis this summer. Public workshops will take place this fall. There will also be a series of open houses conducted in the summer of 2013 as the agency moves forward with conceptual engineering and developing a draft EIS. A final EIS review process will take place in 2015, followed by board selection of the project to be built and a record of decision from the Federal Transit Administration in 2016.

Final design for the segment between S. 200th and Kent/Des Moines is scheduled to be complete by 2019, with construction beginning that same year. Testing would begin in late 2022 with service to Kent/Des Moines starting in 2023. Grant and other funding will need to be secured to construct an extension south of Kent/Des Moines.