Parking sensors are proximity sensors for road vehicles which can alert the driver to unseen obstacles during parking manoeuvres. Parking sensors are used for Automatic Parking System Vehicles, and Intelligent Parking Aid/Assistance System (IPAS) or Advanced Parking Guidance System (APGS). Different types of parking sensors are ultrasonic sensors, ultrasound sensors, laser sensors, radar sensors, etc.

Ultrasonic sensors are popular type of parking sensors. Parking sensor systems use ultrasonic proximity detectors embedded in the front and/or rear bumpers, to measure the distances to nearby objects at low level. Depending on the speed of the vehicle and the distance to the obstacle, the system will warn the driver by visual and/or audible means about the risk of collision. The feedback to the driver will generally indicate the direction and proximity of the obstacle. Warnings are deactivated when the vehicle exceeds a certain speed, and can be switched off for situations such as stop-and-go traffic.

Parking sensors and advanced parking systems are very useful for reverse parking procedure and parallel parking procedure. Parking sensors placed on vehicle rear/back-side are called as vehicle rear sensors or vehicle backup sensors.

Parking sensors and parking aid devices usually generate audio alarms such as “beeps” and/or tones, and visual alerts such as LED or LCD readouts to indicate distance from an object.