OLYMPIA, Wash. (AP) — Democratic leaders in the Washington state House have unveiled a 16-year, $25.8 billion transportation package that includes an 18-cent increase in the gas tax and a new fee on carbon emissions.

Supporters say the new revenue is needed to cover the cost of projects like the replacement of the Interstate 5 bridge over the Columbia River and removal of state-owned culverts that are blocking fish passage.

Under the proposal, $17.6 billion would come largely from the gas tax increase. It would be imposed over the next two years and indexed for inflation going forward.