A 28-year-old Portola Valley woman has been identified as the driver killed in a single-vehicle crash on southbound Interstate 280 near Hillsborough early Sunday, Sept. 20.

The San Mateo County Coroner's Office identified the victim as Maya Raphaella Shustik, the SF Chronicle reported Monday, Sept. 21. Shustik was the sole occupant of a black Volkswagen Tiguan SUV that left the freeway and struck a boulder in the center median.

As we reported Monday, Sept. 21, the crash happened just south of the Black Mountain Road and Hayne Road exit. But the wreck went undiscovered for more than five hours despite triggering an automatic crash notification.

The California Highway Patrol (CHP) Redwood City office said officers were dispatched at 2:09 a.m. Sunday after receiving that alert. Officers, firefighters and paramedics searched the area but could not locate the vehicle in the darkness. Investigators found no witnesses who could help pinpoint its location.

"Officers were called to the scene at that time but could not find any sign of a collision because it was too dark," CHP spokesperson Officer Sophie Lu told SFGate.

The median where the crash occurred is roughly 50 yards wide, filled with dirt and ditches, according to the East Bay Times.

At about 7:31 a.m., authorities received additional calls reporting a crash in the same area. Responding officers found the Tiguan in a ditch.

The CHP's preliminary investigation indicates the SUV was traveling at high speed when it left the roadway for unknown reasons. The vehicle traveled about 500 feet through the median before striking the boulder. The impact was severe enough to move the boulder from its original position, according to the CHP.

Firefighters pronounced Shustik dead at the scene.

Investigators have not determined what caused the crash. The CHP said it is unknown whether Shustik suffered a medical incident, fell asleep or whether speed, alcohol or drugs were factors. A full autopsy report will be reviewed before the agency makes a determination.

Anyone with information about the crash can contact the CHP's Redwood City office.