📖 The Quick Answer
AEB watches the road ahead with forward-facing sensors. When the system calculates that a crash is likely and the driver has not braked, it pre-charges the brakes, gives a visual and audible warning, then applies full braking force on its own. Most modern systems also detect pedestrians and cyclists.
⚙ How It Works (Sensors and Algorithm)
Radar in the grille measures the closing speed and distance to objects ahead. A camera behind the windshield classifies what those objects are (vehicle, pedestrian, cyclist, animal). The ADAS computer fuses both inputs many times per second and computes time-to-collision. When time-to-collision drops below a threshold and the driver has not responded, the system commands the ABS/ESC module to apply the brakes. Some systems pre-tension the seat belts and close the windows and sunroof at the same time.
🛡 What It Protects Against
Rear-end collisions, pedestrian strikes at low to mid speed, cyclist strikes, and some animal strikes. IIHS data shows AEB cuts rear-end crashes by about 50 percent and rear-end injury crashes by about 56 percent.
⚠ Limitations and When It Fails
Heavy rain, snow, or fog can blind the camera and confuse radar. A dirty or iced-over front sensor cover disables the system. Most consumer AEB systems are designed for closing speeds under 50 mph and may not fully stop the car at highway speed. Tight curves, cresting hills, and unusual obstacles (a stopped car partially in lane, a deer at an angle) can also fool the sensors.
🚗 Which Vehicles Have It
Standard on every new vehicle sold in the US since September 2022. Common brand names include Honda Sensing, Toyota Safety Sense (TSS), Subaru EyeSight, Ford Co-Pilot360, Hyundai SmartSense, Nissan Safety Shield 360, GM Forward Automatic Braking, and Mazda i-Activsense.
🔧 Related TSBs and Recalls
Several Honda and Acura models had a 2023 recall (23V-751) for false AEB activation. Tesla Autopilot AEB has been the subject of multiple NHTSA investigations. Always check NHTSA.gov by VIN before assuming your AEB software is current.