The parking sensor option plays a part in helping parking manoeuvres in tight spaces. The system helps prevent damage to the vehicle (and third parties) by identifying rear obstacles located outside the driver's field of vision.Four ultrasound sensors located in the rear bumper use sonar technology to survey the area behind the vehicle. They send incoming information to a microprocessor control unit that combines the data to establish the presence or absence of potential obstacles.The system alerts the driver to potential danger by emitting an intermittent acoustic signal. The signal rate is inversely proportional to distance from the obstacle (the signal is continuous below 250 mm). The device is automatically activated when reverse is engaged. It can, however, be excluded by a special button.