Hi, From what you describe it is possible this person may have suffered from a number of possible problems including, stroke, TIA, epilepsy, hypoglycemia, a cardiac or cardiovascular episode (vasovagal reaction vs. cardiac arrhythmia), or functional syncopal episode. Any time anybody suddenly loses consciousness causing loss of control of a vehicle or otherwise, causing damage due to unawareness of the environment or how they are behaving, etc. should be considered as suffering from a medical emergency. That person should be transported to the hospital for a full and complete evaluation. At the very least they should be restricted from driving a vehicle until further notice. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Dariush Saghafi, Neurologist