Sound Transit’s Proposition 1, hailed by some as “a brighter mobility future,” appears to have passed in Tuesday’s general election.

The $17.9 billion regional measure to expand light rail, commuter train and bus service was well ahead in voting in King, Pierce and Snohomish counties.

An increase in express-bus service is scheduled to begin next year, followed by four more Sounder commuter trains south of Seattle from 2011 to 2015. Money for the expansion will come from an existing sales tax and and a half-cent increase.

“The voters have reversed course from 40 years of debate and inaction and turned towards a brighter mobility future,” said Metropolitan King County Councilman Larry Phillips, a leading supporter of Proposition 1. “Building our mass-transit system will save people time and money, help our local economy, clean up our environment and renew communities.”

He said the region “can now begin digging ourselves out of a 40-year transportation hole toward a better, greener transportation future.”