While operating on a public roadway with Tesla Full Self-Driving (Supervised) engaged, the vehicle unexpectedly departed its intended roadway trajectory. Upon recognizing unsafe vehicle behavior, I attempted to manually override and disengage the system using normal driver control inputs. Despite these attempts, the system did not disengage or yield control in a timely or effective manner. The vehicle continued on an unsafe path, left the roadway, and collided with a fence and a tree before meaningful driver control could be restored. This incident raises concerns regarding the reliability of driver override authority and the systemâs ability to relinquish control during supervised operation.