When a vehicle advances in parallel with a parking frame to reach an initial
stop position, measurement of a distance to a parked vehicle is continuously performed
by means of an ultrasonic sensor and a moving distance of the vehicle is simultaneously
calculated using a signal from a wheel speed sensor. When actuating an in-line
mode switch under a state where the vehicle stops in the initial stop position,
a turning angle is calculated so as to enable appropriate in-line parking to the
parking frame from an actual initial stop position, based on a deviation of the
vehicle from a reference position for the initial stop measured by the ultrasonic
sensor. Information on a driving operation that is necessary for back parking is
provided to a driver via a speaker based on this turning angle and output from
a yaw rate sensor.
