An autonomous driving system for vehicles includes: an autonomous driving controller for controlling autonomous driving of a host vehicle based on information of nearby vehicles and requesting warning and handover upon determining that a failure in autonomous driving of nearby vehicles has occurred; a communication controller for requesting the warning and handover; selecting an emergency target vehicle and requesting a driving mode of following the emergency target vehicle upon receiving autonomous driving failure information; a human-machine interface device for outputting warning and handover information in response to the request of the autonomous driving controller and the communication controller; and a host vehicle driving controller for controlling driving of the host vehicle in response to the request of the autonomous driving controller and the communication controller.