I-5 detours to begin for diverging diamond project in Lacey

LACEY, Wash. — Starting Tuesday, construction is set to ramp up on a diverging diamond project in Lacey.

The crisscrossing lanes will be at the Marvin Road interchange.

Crews will set up a detour and close a lane in both directions across the I-5 overpass for construction. An estimated 34,000 cars use the overpass daily.

Drivers will have to take detours onto nearby streets instead of their normal routes for at least two months.

A video created by the Washington State Department of Transportation shows how the diverging diamond interchange will look. (Story continues below video.)

Cars will be directed to the other side of the road, sending them onto the highway without stopping.

WSDOT officials say the configuration will make traffic flow more efficiently with less chances for crashes.

"I think it's going to make it worse for a while, but it's one of those deals where it's going to get worse before it gets better, but there is a light at the end of the tunnel,” said driver Joe Wichman.

The project will also add a new frontage road which runs parallel to southbound I-5.

The project is expected to be completed in late 2020 or early 2021 and is the first of its kind in the state.

WSDOT says there could eventually be diverging diamond interchanges in Fife and Snoqualmie as well.

Cox Media Group