A car speeding onto a highway on-ramp on the way out of downtown San Diego slammed into a sign, then a guardrail and ended up on its roof.
One passenger was killed in the crash, another injured. The driver, described as a man in his 20s, was arrested and booked on suspicion of driving under the influence.
The accident happened just after 2 a.m. Monday on the 11th Avenue on-ramp to northbound I-5.
California Highway Patrol officers say the driver of the car collided with a street sign and then with a guardrail on the other side of the street before flipping the car.
One of the female passengers was trapped inside the car and pronounced dead at the scene according to the CHP. Her identify will be withheld until family can be notified.
Another female passenger was taken to the hospital for minor injuries.
The unidentified driver was arrested and will be booked for felony DUI, officers said.