Investigators say 55-year-old David Nelson of Victorville appeared to be speeding in the southbound lanes when his car went off the shoulder south of Kenwood near the interchange of the 15 and 215 freeways.
The vehicle went up a dirt embankment, then rolled back onto traffic lanes of the freeway, blocking two of the lanes for several hours.
No one else was in Nelson's car, and no other vehicles were involved in the accident.
Nelson was court services deputy and a 22-year veteran.
