Around 6:55 a.m., the woman was getting out of her silver, four-door 2010 Lexus when a man armed with a gun approached her, demanded her car and drove off in it, BART police Officer Era Jenkins said.
The woman was not physically injured during the incident.
The suspect is described as a black man in his 20s who is about 5 feet 5 inches tall with a light complexion. He was armed with a small silver handgun and was wearing a dark hoodie, Jenkins said.
The man remains at large and the car is still missing. BART police are asking any witnesses to the crime or anyone with information about the suspect to call (510) 464-7000.