Transit Development Plan

Passengers exit Sounder train and board buses at the Puyallup Station.

The Transit Development Plan (TDP) provides updated information to the Washington State Department of Transportation (WSDOT) on various elements of public transit service delivered by Sound Transit. It contains details on the agency's goals (and how they align with state & local long-range priorities), performance measures and targets, planned capital improvements and operating changes for the next six years, and a multiyear financial plan overview. 

As a public transit agency in the state of Washington, Sound Transit is required annually to prepare a six-year Transit Development Plan per RCW 35.58.2795. WSDOT may use this document to prepare an annual report for the Washington state legislature summarizing the status of public transportation systems across the state.