State Route 7 will have one alternating lane near Eatonville starting Tuesday (Aug. 25).
Crews working to reinforce the hillside after a mudslide last year will make the road one lane near 416th Street East.
A temporary traffic signal will direct the one-way alternating traffic, the state Department of Transportation said.
The speed limit between mileposts 29.5 and 31.5 will be reduced from 50 miles per hour to 35 mph, and for part of that stretch to 25 mph, to prepare drivers to stop at the signal.
Crews expect to work through September.