Driving assistance device

A driving assistance device that performs a notification process for notifying a driver of a risk of a collision with a preceding vehicle in cooperation with a predetermined notification device, the driving assistance device comprising:

• an inter-vehicular distance acquisition section that successively acquires an inter-vehicular distance between the preceding vehicle and an own vehicle;
• a first index calculator that calculates a first risk index that is a parameter indicating a degree of the risk of the collision between the preceding vehicle and the own vehicle based on a traveling speed of the own vehicle and the inter-vehicular distance acquired by the inter-vehicular distance acquisition section;
• a second index calculator that successively calculates a second risk index that is a parameter indicating the degree of the risk of the collision between the preceding vehicle and the own vehicle, the second risk index being different from the first risk index, based on a relative speed between the own vehicle and the preceding vehicle;
• a notification level determination section that successively determines a notification level indicating a strength of notification for notifying the driver of the risk of the collision with the preceding vehicle, based on the first risk index calculated by the first index calculator and the second risk index calculated by the second index calculator;
• and
• a notification processor that performs the notification process in a notification mode corresponding to the notification level determined by the notification level determination section, wherein:
• the notification level determination section determines the notification level in a plurality of stages;
• a lowest one of the plurality of stages of the notification level is a level in which the notification processor does not perform the notification process;
• as the notification level determined by the notification level determination section becomes higher, the notification processor performs the notification process in a notification mode that more strongly notifies the driver of the risk of the collision with the preceding vehicle;
• and
• the notification level determination section sets the notification level to be a lower level than an original notification level determined based on a present first risk index and a present second risk index when at least one of the first risk index or the second risk index is shifted to a value indicating a safer state under a condition that the notification processor performs the notification process.