The state Department of Transportation on Monday opened a new southbound lane along I-405 from Southeast Eighth Street to I-90, bringing relief to commuters through Bellevue.

The new lane is part of the $124 million I-405 South Bellevue Widening Project that expands four miles of 405 between 112th Avenue Southeast and Southeast Eighth Street.

“We’re making progress on the I-405 corridor – one of our most congested in Washington,” said Washington Transportation Secretary Paula Hammond. “We’ve invested nearly $1.5 billion into I-405 since 2003 and we’re seeing speeds improving in some of our worst chokepoints.”

Since January, northbound I-405 travelers are seeing an increase in travel speeds due to the opening of a new northbound lane from 112th Avenue Southeast to I-90. South-end commuters are benefiting from increased speeds and reduced morning commute times as they head north into Bellevue.

Improvements are expected for southbound commuters in the afternoon, said WSDOT Project Engineer Seema Javeri.

“We anticipate the additional lane will speed up traffic and increase safety in the area once restricted by the tunnel,” she said.

Over the summer, crews will widen northbound I-405 between I-90 and Southeast Eighth Street. Traffic will be shifted from the northbound carpool lane to the bridge that used to carry southbound traffic over I-90. Crews also will add an additional southbound carpool lane between Southeast Eighth Street and I-90.

The project is funded by the 2003 and the 2005 gas tax packages.

For more information on the project, visit www.wsdot.wa.gov/Projects/i405/.