SEATTLE -- Seattle Mayor Greg Nickels is proposing new property taxes to repair streets and bridges, including the Alaskan Way Viaduct.

He introduced the idea in his state of the city address Monday night, asking voters for at least $25 million a year in new property taxes.

He said he wants to raise the extra money it will take to replace the Alaskan Way Viaduct with a tunnel, rather than with a new elevated structure.

The amount and type of ballot measure hasn't been determined. It also wasn't immediately clear what it would cost the average homeowner in Seattle.

City officials have said replacing the viaduct with a tunnel would cost $4.4 billion.