California Highway Patrol press release: 

On 5/13/2016, at approximately 2:10 PM, a 2004 Chevrolet pickup driven by a single female occupant, was traveling southbound on US-101 south of Underpass Road in Mendocino County.  For reasons still under investigation, the pickup drifted to the right (west).  The pickup moved onto the right shoulder, onto a wooded embankment, and collided with several trees.  The driver sustained fatal injuries and was pronounced deceased at the scene.  It is not known at this time if alcohol or drugs were a factor in the cause of this collision.

The identity of the female driver is currently being withheld pending notification of next of kin.

This collision remains under investigation by the California Highway Patrol.