Southbound Interstate 5 express lanes opened shortly after 8 a.m. Thursday after a stuck contractor vehicle delayed the scheduled opening, according to the Washington State Department of Transportation.

Around 7 a.m., the closure had caused an 11-mile backup from around 220th Street in Mountlake Terrace to Roanoke Street in Seattle, according to the department.

“Lengthy backups remain, so expect large delays/leave early or use alt. routes for a bit longer!” the department said on Twitter shortly after 8 a.m.

A hydraulic failure of a bucket truck was the cause of the delay, the department said.

I-5 express lanes help traffic flow during busy travel times and move in the direction that will relieve the most congestion, according to WSDOT. The lanes are open on a daily schedule that changes on weekends and occasionally for major events.

Southbound I-5 express lanes are typically open weekdays from 5 to 11 a.m. and weekends from 8 a.m. to 1:30 p.m. Northbound I-5 express lanes are typically open weekdays from 11:15 a.m. to 11 p.m. and weekends from 1:45 to 11 p.m.