A parking assistance device includes: an obstacle detection unit that detects an obstacle; a separated distance determination unit that determines a separated distance between the obstacles when a plurality of the obstacles are detected; a target position determination unit that determines a target position in a guidance route; a route calculation unit that calculates the guidance route; and a control unit that guides a vehicle in accordance with the guidance route, wherein, when a second obstacle is detected in a second direction orthogonal to a first direction in which one or plurality of first obstacles extends or are lined up while being separated from each other and at a position separated from the first direction, the separated distance determination unit determines the separated distance between the first and second obstacles.

A method for ascertaining a parking area of at least one street section includes providing information indicating a usable width of the street section, the usable width representing a drivable width of the street section between spaces for parked vehicles at the two lateral sides of a driving vehicle; the driving vehicle driving the street section and ascertaining lateral distances from objects using an ascertainment device situated in the driving vehicle; comparing the ascertained lateral distances to the usable width; and ascertaining the parking area by way of the comparison.

A method for classifying objects in the environment of a vehicle with the aid of ultrasonic sensors. In the method, ultrasonic signals are emitted, ultrasonic echoes are received from objects in the environment, and the position of a reflection point relative to the ultrasonic sensors is determined using lateration, reflection points being continuously determined and the reflection points being allocated to objects in the environment. Dispersion parameters relating to the position of the reflection points allocated to an object are determined and used as a classification criterion with regard to the type of object. A driver assistance system and a vehicle including such a driver assistance system, are also described.