The Sound Transit Board kicked off a public involvement campaign to decide what mass transit projects should be studied as the final candidates for a Sound Transit 3 ballot measure.

Community members throughout the fast-growing Puget Sound region can engage on ST3 priorities via an online survey, a new interactive website, public meetings and social media.

“Continued expansion of our successful transit system through ST3 is critical to keeping our people and our economy moving,” said Sound Transit chair and King County Executive Dow Constantine. “It’s a pivotal time at Sound Transit, and we invite our riders to be a part of it.”

The Sound Transit Board is seeking input on a draft list of projects to be considered possible candidates for the ST3 measure.

After collecting input on the Draft Priority Projects List, the Board will identify a final list of projects to be studied this fall. The results of those studies will support further narrowing by the Board to shape a draft ST3 measure for public input in early 2016.

Potential projects emphasized so far by the Sound Transit board and earlier public input include but are not limited to building light rail extensions to Everett, Tacoma, downtown Redmond, Ballard and West Seattle, as well as bus rapid transit on I-405 and improving Sound Transit Express bus and Sounder commuter rail services and facilities.

An interactive Sound Transit 3 website — soundtransit3.org — offers community members a chance to learn more about regional transit benefits, explore potential projects and take a survey through July 8.

The campaign to promote public involvement will include Facebook posts and Twitter dialog using the #ST3 hashtag. Public meetings will also be held around the region, including in Federal Way.

That meeting will run from 5:30-7:30 p.m. on June 25 at the King County Aquatic Center, 650 S.W Campus Drive.

The meeting will coincide with King County Metro Transit Long-Range Plan public meetings (more information at kcmetrovision.org).

For the ST3 measure to be considered by voters in November 2016, the Washington State Legislature must first grant the region additional local revenue authority.

Members of the Sound Transit board are seeking $15 billion in new revenue authority and have emphasized it is critical for the Legislature to act on this and a statewide package of transportation investments before the current special session ends.