sound transit 3 is an approved 2016 ballot measure that will expand sound transit services with $54 billion in funding (combining local taxes and federal grants) over a 25-year period beginning after the completion of sound transit 2. the measure will add of light rail, with the completed system carrying an estimated 500,000 riders per day. the plan also funds sound transit express bus routes, adds two bus rapid transit lines and expands sounder commuter rail with longer trains, potentially better frequency and two additional stations in tillicum (near joint base lewis–mcchord) and dupont.