Freeway expansion work on Interstate 5 from Grand Mound to Centralia in the US state of Washington has entered its final phase.

The Washington State Department of Transportation (WSDOT) is widening the I-5 to three lanes while excavation work along the east of the freeway is underway to create new shoulders.

The agency plans to commence work on the inside lanes of the freeway next year following the completion of shoulder areas.

The project is part of WSDOT’s $390m Interstate 5 widening project that covers 18 miles from the Littlerock area to the Lewis-Thurston county line.

The entire project will be complete by next year, according to