A 30-year-old driver without a seat belt died after her crash crashed into a tree just south of Spring Street in Spring Valley, the California Highway Patrol (CHP) said.
The crash happened at approximately 2:39 p.m. when the woman, from El Cajon, was driving a Honda Civic at a "very high rate of speed" on State Route 94 at State Route 125 CHP officials said.
At the last minute, the driver made an unsafe turning movement to the left to try to get on the southbound SR-125 transition road, officers said.
She lost control of her car and went down an embankment, hitting a large tree. No other cars were involved.
The driver, who was not wearing a seat belt, was pronounced dead at the scene. It does not appear drugs or alcohol were a factor.
The car went off the right hand shoulder and hit a tree, CHP said.
CHP officers are investigating.
No further information was immediately available.