Vehicle driving assistance device and vehicle driving assistance method

A vehicle driving assistance device, comprising:

• a sonar device configured to acquire sonar information using an ultrasonic wave, the sonar information including information on a target positioned around a host vehicle and information representing a reflection intensity of the ultrasonic wave reflected by the target;
• a radar device configured to acquire radar information using a radio wave, the radar information being information on the target positioned around the host vehicle;
• a surrounding environment information acquisition device that acquires surrounding environment information on a surrounding environment of the host vehicle;
• and
• a controller configured to:
• determine whether the reflection intensity included in the sonar information is lower than a predetermined intensity threshold value;
• determine whether the host vehicle is positioned in a parking lot based on the acquired surrounding environment information;
• determine whether both the sonar information and the radar information include information on the same target;
• determine whether an immediately-after-startup condition is satisfied, the immediately-after-startup condition being satisfied when a current time is within a period from a first point of time at which the host vehicle is started so that the host vehicle becomes able to start moving to a second point of time at which a predetermined traveling determination condition is satisfied, the predetermined traveling determination condition being satisfied when the host vehicle starts traveling;
• determine whether a driver of the host vehicle is assumed to have erroneously depressed an accelerator pedal of the host vehicle;
• integrate the sonar information and the radar information to generate sonar/radar fusion target information that includes a position of the target and a relative speed between the host vehicle and the target;
• and
• execute automatic braking for the host vehicle based on the sonar/radar fusion target information in a case where determinations are made that (i) the reflection intensity is lower than the predetermined intensity threshold value, (ii) the host vehicle is positioned in the parking lot, (iii) both the sonar information and the radar information include the information on the same target, (iv) the immediately-after-startup condition is satisfied, and (v) the driver of the host vehicle is assumed to have erroneously depressed the accelerator pedal.