Accident happened while driving on a two-way county road without center lane markings. The driver was leaning to the right of the road. The lane keep assisting overcorrected to the left hitting a culvert. Upon the crash the seat unlocked from its position and slid towards the steering wheel. The seat belt did not lock in time to prevent the seat from considerable forward movement. The airbag located inside steering wheel seemed only partially inflated. No other airbags deployed. The combined malfunctions resulted in the driver's left foot being crushed (various fractures and joints dislodged), and right ankle fracture and dislocation. The driver was the only one involved in the cash. However, other drivers could have been affected by the sudden change of lanes - especially if driving the opposite direction. The issue has not been reproduced as far as known (unable to find any reports, images or videos online). There was no inspection following the accident. The car had previously shown unexplainable lane keeping assistance overcorrections before, but there were no system failure warning lights. The seat sometimes needed readjustment (the locking system would click, but the seat would not remain in place). Summary of issues: -Lane keep assisting - overcorrected leading to hitting a culvert on the opposite side of the road. -Driver's seat unlocked forward toward the steering wheel when car hit the culvert. -Seatbelt did not lock appropriately to prevent seat moving for