The violent crash was reported at about 5:20 a.m. near Atlantic Avenue, prompting the closure of all eastbound lanes for several hours, according to the California Highway Patrol.
CHP started receiving 911 calls about a wrong-way driver speeding west in the eastbound lanes 10 minutes before the deadly crash.
Police say the wrong-way driver - a 21-year-old Palmdale woman driving a Honda sedan - crashed into a 30-year-old Hemet woman driving in the carpool lane.
Both drivers died at the scene.
The freeway was closed nearly six hours for the investigation.
UPDATE: All lanes OPEN https://t.co/IQgSD7zqdK
— Caltrans District 7 (@CaltransDist7) July 25, 2021
All lanes were reopened shortly before 11 a.m., Caltrans said.