Starting at 7 o'clock tonight, work crews will shut the bridge down to begin work on what are called the "approach slabs".

"Not real glamorous work but essentially it's a 12" thick concrete slab that connects the bridge to the roadway."

Steve White is an engineer with the county's Transportation Department. He's heading up the Hazel Bridge expansion…which will widen the bridge from four-to-six lanes and add space for bikes and pedestrians.

White told Capital Public Radio's Insight that the bridge should be back open by Monday morning at 6. But it is construction and anything can happen.   

"There is a fallback plan. In worst case scenario we would have to just plate over the piece that they're working on and we could reopen up the bridge at 6 AM."

Money for the $20 million bridge expansion comes from Measure A sales tax funds as well as some federal highway money. The project is expected to be completed by mid-February.