For the second consecutive year, King County voters face a measure aimed at traffic decongestion on the general election ballot.

This year’s Sound Transit 2 (ST2) proposal, or Proposition 1 is different from last year’s Roads and Transit measure (which voters rejected) in that it includes transit only and comes at a smaller price.

“The whole idea of what is on the ballot” for next Tuesday’s general election “is a totally different animal,” Sound Transit spokeswoman Linda Robson said. “Half of the projects and half of the costs are eliminated.”

Expanded light and commuter rail, as well as bus services, are proposed through a 15-year construction plan, starting in 2009. ST2 would cost King, Pierce and Snohomish county residents a total of $17.8 billion, including inflation, maintenance and debt service, among other costs.

“The feedback that we got from voters on the 2007 package was it was just too big and too costly,” Robson said. “This package responds to that criticism.”

Voters are being asked to approve a 0.5 percent sales tax increase, equivalent to about $69 per year per adult. A little more than half of ST 2’s capital costs would be funded through grants and cash revenues, according to Sound Transit. Long-term bonds lasting the duration of the construction period, and approximately $895 million in federal matching grants, would also help pay for the transit improvements.

“What it means on the citizen’s side is half a penny more on the sales tax,” Robson said. “We’ll let the voters make up their minds if they think that is something affordable or not.”

Last year’s ballot measure proposed by the regional transit agency was for a 0.5 percent sales tax increase, which would have funded the transit side of the measure, and a 0.8 percent motor vehicle excise tax increase that would have gone toward the road improvements. The measure would have cost $47 billion, in year-of-expenditure estimates, and $17.8 billion — $7 billion for roads and $10.8 for transit — in 2006 dollars.