The large mixer truck crashed on the on-ramp from westbound state Route 52 to northbound I-5 shortly before 5 a.m., according to the California Highway Patrol. The on-ramp was subsequently closed and a SigAlert was issued, authorities said.
Authorities also closed two lanes of I-5 as they maneuvered a tow truck to right the overturned truck. The closures caused a major backup on northbound I-5 during the morning commute.
The cause of the accident is under investigation.