LYNNWOOD — A busy highway construction season this year will mean some delays and lane closures but better traffic flow and safety when it’s all done, state transportation officials say.

Significant work is planned for the entire Puget Sound region. More than $370 million in projects are pla

nned for Snohomish County alone.

Biggies include widening of Highway 522 south of Monroe; repairs to girders on the U.S. 2 trestle near Everett; and continued work on new ramps where I-5 and I-405 intersect in Lynnwood.

Some of the work began last year and will continue through part of this year or beyond. Some closures will be needed and drivers should plan ahead and drive cautiously through construction zones, officials said.

Major regional projects include the early stages of the $4.5 billion replacement of the Highway 520 floating bridge across Lake Washington, and the $3.1 billion tunnel along the Seattle waterfront to replace the Alaskan Way Viaduct.

These two Seattle mega-projects are being financed with federal funds and planned tolls, in addition to state gas tax money.

State money for all the projects comes from two increases in the state gas tax: a hike of 5 cents per gallon in 2003 and an increase of 9.5 cents per gallon approved in 2005, phased in over four years.

Backed by these tax hikes, the state sold $15.5 billion in bonds to get the projects started quickly, state Transportation Secretary Paula Hammond said Tuesday.

Now, that money is beginning to run out. The tax money is still going toward paying off the bonds, she said.

Federal tax dollars also are beginning to dry up.

“What’s next?” she said. “How do we fund our transportation system for the future?”

The bond money was targeted for 421 projects, Hammond said. About 300 are done and nearly 50 more have begun, meaning 84 percent of the bond money backed by the tax hikes has been spent or is being spent.

“We’re living on it and we’ve spent it,” Hammond said.

Bill Sheets: 425-339-3439; sheets@heraldnet.com.

Major road projects in Snohomish County

Highway 522 widening, Snohomish River Bridge to U.S. 2, Monroe

Cost: $159.5 million

Start: Late spring 2011

Finish: Fall 2014

Highway 9 widening, 212th Street SE to 176th Street SE, Clearview

Cost: $87.3 million

Start: Summer 2011

Finish: Fall 2013

Ebey Slough Bridge, Highway 529, Marysville

Cost: $42.3 million

Start: July 2010

Finish: Late 2013

I-5, I-405 merging ramps, Lynnwood

Cost: $33.8 million

Start: August 2010

Finish: December 2011

U.S. 2 at Highway 522, connecting ramp, Monroe

Cost: $22.8 million

Start: June 2010

Finish: Summer 2012

Highway 9 widening, Lundeen Parkway to Highway 92, Lake Stevens

Cost: $22.5 million

Start: July 2010

Finish: December 2011

U.S. 2 trestle girder repair, Everett

Cost: $8 million

Start: Spring-summer 2011

Finish: Late fall 2011

I-5, Everett to Marysville, repaving, installing cameras and electronic signs

Cost: $2.9 million

Start: Spring-summer 2011

Finish: Late fall 2011