A system and method for assisting a driver are provided. The method includes receiving, by a controller, vehicle traveling information and calculating a first distance between a present vehicle position and an end node. In addition, the controller is configured to calculate a second distance between the present vehicle position and a preceding vehicle based on the receiving information and calculate a third distance in which coasting is available until a present vehicle speed reaches a predetermined target speed. The method further includes determining, by the controller, whether coasting is available based on the first distance, the second distance, the third distance in which coasting is available, and a present vehicle speed of the vehicle, and outputting, when coasting is available, a message that instructs coasting.