City police are looking for a man who jumped a cab driver and drove off with his car Wednesday morning. It happened shortly after 2:00 a.m. Police say a man called for a taxi at the Chestnut Street Pub. The driver then took him to 17th and Chestnut, where the man asked to be dropped off. The passenger asked the driver if he had change for a twenty-dollar bill then attacked the driver with an unknown weapon. The driver was able to get out of the vehicle. The passenger hopped in the front seat and drove off with his car. Police found the car wrecked later in the 400 block of Huron Street. The driver was taken to Hamot Medical Center with serious injuries.