This is the third of nine weekend closures to replace aging expansion joints.
At 10 a.m. Saturday morning, traffic was crawling by in the southbound I-5 lane near Yesler Way, and the Washington State Department of Transportation said the lanes started to jam at 9 a.m.
Less than two hours later, WSDOT reported the backup approaching Downtown Seattle from SB I-5 was at least 35 minutes.
WSDOT is alerting drivers that to avoid congestion, SR-99 or I-405 are good alternative choices. And with the southbound construction congestion extending to Mercer Street, drivers can attempt to best the backups by taking SR-99, said WSDOT.
Express lanes will operate in the southbound direction from 8 a.m. until 3 p.m. Saturday, Sunday, and Monday.
Crews hopes to end this latest closure by 5 a.m. Tuesday.