A brake system for a vehicle can be operated without a driver. It has a service brake device, a parking brake device and an emergency braking device. At least the wheel brake devices of the wheels of one axle of the vehicle have emergency brake actuators which switchover the assigned wheel brake devices into the braking state as a result of the triggering of an emergency braking operation. The emergency braking operation can be triggered either manually by means of an emergency operator control device or automatically by means of a monitoring device if the latter has detected an unacceptable operating state of the vehicle in the driverless operating mode.