SACRAMENTO -- Several lanes of southbound I-5 were closed at Seamas Avenue due to a traffic accident that occurred just before 6 a.m. Friday.
Traffic was backed up all the way to the Sutterville Road exit for about an hour.
Two cars were involved in the accident and one vehicle overturned.
CHP doesn't know the exact cause but believe speed, dusk lighting and curve in freeway contributed to the accident.
At least two people were transported to the hospital with serious injuries.
CHP crews cleared the scene around 7 a.m. and all lanes were reopened.
Stay with FOX40 for updates on this story.