The present disclosure relates to a method for assisting a driver of a vehicle comprising the steps of: - a lateral control system (5) of the vehicle (22) performing a lateral control of the vehicle (22) in an autonomous mode (110), - determining information about a surroundings of the vehicle (120), - checking whether a longitudinal control of the vehicle (22) performed by the driver is appropriate considering the determined information about the surroundings (130), and - if appropriate, continuing the autonomous mode of the lateral control. The disclosure also relates to a driving assist system (1) of a vehicle (22), the system comprising - a detection means (3) for determining information about the surroundings of the vehicle (22), - a lateral control system (5) for an autonomous lateral control of the vehicle (22), - a longitudinal control means (7) for performing longitudinal control of the vehicle (22), and - a checking system (9) for checking whether a longitudinal control of the vehicle (22) performed by a driver of the vehicle (22) is appropriate considering the determined information about the surroundings.