How the system works
Vehicle radar uses reflected radio waves to estimate object position and relative movement. Cameras capture visual information and help interpret signs, markings and road-user categories. Ultrasonic sensors use short sound pulses and echoes, often for nearby obstacles in parking. LiDAR measures distance with light to create spatial observations. Bosch documents different roles for the sensors and describes combining sources into a broader view of the surroundings. A vehicle does not need every sensor type to provide every driver assistance function.
What it can and cannot do
Each technology fails differently. Cameras rely on visibility and can struggle with glare or obscured lenses. Radar returns depend on reflectivity, geometry and signal processing. Ultrasonic detection is usually short-range. Optical sensors may face reduced performance when the beam path is obstructed. Fusion can help compare independent measurements, but an incorrect classification or missing target is still possible. Counting the number of cameras is therefore not a scientifically grounded proxy for safety performance.
What changes between vehicles
A front radar may serve ACC and frontal collision detection; side radar may support blind-spot warning; close-range cameras or ultrasound may be used for parking. Software decides how observations become warnings or actions. Different hardware can support superficially similar branded packages, even within one nameplate. A camera housing visible through the windscreen cannot verify pedestrian AEB, lane centering or traffic-sign recognition in a particular regional trim.
Buying and ownership implications
Sensor mounting geometry matters. Bumper repairs, windscreen replacement and some alignment work may require OEM-specified calibration. IIHS has documented the additional cost and difficulty of repairing crash-avoidance systems. Do not reposition brackets, paint sensor covers or apply generic calibration values. Persistent blocked-sensor messages or poor performance warrant professional evaluation, not an improvised test involving a person or an obstacle placed in traffic.
Regional and model-year caveats
For a 2020–2026 global archive, document which production variant actually uses which sensors and what each supports. Some regional trims omit hardware despite identical exterior panels. Supplier marketing explains engineering principles but is not model-level fitment proof. Buyers should prioritize documented operating limits, transparent system alerts, service support and credible independent evaluations instead of speculative claims of full autonomy.