A massive expansion of public transit service, including 62 new miles of light rail, additional rapid bus service and Sounder trains, and new transit infrastructure, will be built in the Puget Sound region over the next three decades.

Initial election results showed voters approved Sound Transit 3, a $54 billion measure, with 55 percent of voters approving the measure Wednesday afternoon. ST3 is funded by tax increases. The measure is expected to cost an average adult $169 in tax increases, according to Sound Transit.

ST3 passed in King and Snohomish Counties with 58 percent and 52 percent of ballots cast for the initiative, respectively. Pierce County rejected the measure with 56 percent of ballots cast in opposition.

King County Executive Dow Constantine addressed the crowd shortly after numbers from King Co. rolled in, and compared ST3 to major milestones like the construction of the Space Needle and the founding of Microsoft.

“These are the kinds of things, the bold moves, that have defined this region,” Constantine said. “We have taken another step just like that.”

ST3 will bring light rail service to West Seattle and Tacoma in 2030, Ballard in 2035, Everett in 2036, Issaquah and Kirkland in 2041.

Supporters say it would offer an alternative to the region’s increasingly jammed roads, an escape from gridlock, as an estimated one million newcomers arrive in the region.

Opponents blasted the measure’s massive price tag and built their campaign on the prediction that ST3 would not reduce traffic congestion and might not reduce commute times.

They also expressed concerns that light rail could become obsolete as ride-sharing and driverless car technologies rapidly improve.