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History: what voters approved

Sound Transit plans, builds and operates express bus, light rail and commuter train services and serves the urban areas of King, Pierce and Snohomish counties.

Sound Transit 3

Connecting the region's cities with mass transit and completing the light rail spine

In 2016, the region's voters approved the Sound Transit 3 (ST3) ballot measure. This 25-year program will expand the mass transit network to connect 16 cities with light rail, 30 cities with Bus Rapid Transit and ST Express bus service and 12 cities with commuter rail. With major projects completed every five to seven years, ST3 further extends the light rail system beyond previously-approved extensions being built to Northgate, Shoreline, Lynnwood, Mercer Island, Bellevue, Overlake and Kent/Des Moines.

Highlights include:

  • Builds 62 new miles of light rail to complete a 116-mile system with extensions to Everett via the Paine Field Industrial Center; Tacoma via Federal Way and Fife; downtown Redmond; Ballard via South Lake Union and Seattle Center; West Seattle; and a new light rail line from south Kirkland through Bellevue to Issaquah.
  • Adds Bus Rapid Transit on major highways to the north, east and south of Lake Washington with service every 10 minutes during peak hours.
  • Extends Sounder south train platforms to accommodate trains of up to 10 cars in length to serve up to 40 percent more passengers; expands Sounder south service from Lakewood to DuPont; and improves access and parking at stations along the north and south lines.

Documents: Sound Transit 3 Plan »

Sound Transit 2

Expanding the regional mass transit system

In 2008, the region's voters approved the Sound Transit 2 (ST2) ballot measure. This 15-year program authorized substantial additions to ST Express bus and Sounder commuter rail service, plus 36 miles of new Link light rail service to form a truly regional system. Highlights include:

  • More ST Express bus service on the busiest routes
  • Four new daily Sounder round trips on the popular south line, plus improved station access
  • Link light rail service north to Lynnwood, east to the Overlake area and south of Sea-Tac Airport

Documents: Sound Transit 2 Plan »

Sound Move

In 1996, voters approved Sound Move, the first phase toward realizing the long-term vision of a regional high capacity transit system. This vote authorized the creation of Sound Transit, tax collections for funding, and the first set of regional transit projects. These included: 

  • Light rail service between Sea-Tac Airport and the University of Washington, with a northward extension to Northgate dependent upon additional funding
  • Peak period commuter rail from Lakewood and Everett to Seattle
  • ST Express bus routes linking the region's population and employment centers
  • Capital investments in transit facilities (transit centers, park-and-ride lots, etc.) plus HOV direct access ramps that improve bus speed and reliability

Sound Move documents

Planning history

Sound Transit has been building the foundation of the regional mass transit system approved by voters.

Many historical system planning documents are available online.

Planning documents 

Not all documents are on the website. Contact us if you have questions.