Southbound I-5 in south King County receiving an upgrade

The ride to Pierce County from Seattle is expected to get a bit tricky

for drivers who make the trip overnight or on weekends.

That’s when crews hired by the state Department of Transportation will begin an 18-month project to replace aging expansion joints and worn pavement on a 13-mile stretch of southbound Interstate 5 between Tukwila and Federal Way.

“This section of I-5 is more than 50 years old, and it’s showing its age,” said Mike Askarian, a Transportation Department project engineer. “It’s time to restore it. With several months of work, we can keep traffic moving on our region’s main highway for decades to come.”

The $27.3 million project will:

▪ Replace 235 concrete panels and expansion joints on the Duwamish River bridge.

▪ Repave I-5 between South 188th Street in SeaTac and South 219th Street in Des Moines.

▪ Resurface the freeway by grinding out ruts and cracks in several locations.

Most of the work will be from 8 p.m. to 6 a.m. Sunday nights to Friday mornings. Lane reductions during those times are expected.

The biggest effects on traffic likely will be in July and August.

That’s when crews will reduce a 3.5-mile stretch of southbound I-5 to two lanes starting at the state Route 518 on-ramp. The lane reductions will take place over five yet-to-be-determined weekends.

Askarian said 86,000 cars per day use I-5 between Southcenter and Des Moines on a typical weekend day.

“To limit congestion, we need about 50 percent of drivers to use other routes or postpone their trip on the weekends when southbound I-5 is reduced to two lanes,” he said.

The Transportation Department recommends drivers take alternate routes such as state routes 167, 99 or 509, or that they ride the bus or take light rail during those weekends.

This story was originally published March 18, 2016 at 2:53 PM with the headline "Southbound I-5 in south King County receiving an upgrade."