In our previous article, we looked at camera sensors, which see the world through your windshield. In this edition we examine radar sensors, usually mounted in or hidden behind the front bumper or grille.
They work by transmitting a high-frequency radio signal that bounces off objects and returns to the car. The distance to these objects is calculated by the time it takes to receive the return signal.
Radar sensors provide input for ADAS functions such as adaptive cruise control, forward collision warning and automatic emergency braking. They may also monitor blind spots and give you rear-collision warning when reversing, via sensors mounted under side-view mirrors, behind the rear bumper or in the tail lights.
Incorrect calibration or the slightest bumper damage can compromise signal reception. In fact, too much paint on a bumper cover can even cause a problem; and placing a bumper sticker anywhere near a radar sensor is certainly not advised!