People who take Highway 99 during the late evening to early morning hours may face delays.
Additional lanes are being put in between East First Avenue and the Highway 32 junction.
Those ramps, and various north and southbound lanes will be closed from 9 p.m. to 7 a.m. every day through Friday.
Only one ramp will be closed at a time and construction is also being done on the Butte Creek Bridge.
Drivers can expect the north and southbound lanes between Estates Drive and Southgate Ave. to be closed on and off from 9 p.m. to 6 a.m. until Thursday morning.