Caltrans spokesman Dennis Keaton said drivers should brace themselves for a tough commute.
With the westbound phase of the Fix50 project under way, Highway 99 is backing up because of congestion on the connector ramp.
"We're trying to get commuters (not to take that ramp) and to go up Business 80 instead to N Street."
Westbound traffic on 50 has become a concern too for Caltrans. "It could be a long commute this morning," Keaton said.
Motorists are advised to avoid the connector ramp from northbound 99 to Highway 50 because the right lanes are at a standstill.