The bus crashed early Thursday after the Chevy Trailblazer overturned in front of it on Highway 99 in the Fresno area. Six people died, and nearly two dozen bus passengers were injured.
Authorities initially said 19-year-old Vanessa Gonzalez of Fresno was behind the wheel of the SUV.
The CHP said Monday that Sylvia Lopez Garay of Dinuba was driving and had a blood alcohol level above the legal driving limit. Twenty-year-old Stephanie Cordoba of Fresno also was killed in the wreck.
Friends and relatives say the three women had come from a dance party in Fresno's Tower District.