Forward Collision Warning (FCW)

Forward collision warning, or FCW, uses sensors such as cameras and radar to watch the road ahead. If the system predicts that a crash is likely, it warns the driver with a sound, a visual alert, or a vibration so they can brake or steer. FCW is usually paired with automatic emergency braking (AEB), which applies the brakes itself if the driver does not react in time.

These systems are on track to become standard equipment. NHTSA's final rule creating Federal Motor Vehicle Safety Standard No. 127, published May 9, 2024, requires forward collision warning and automatic emergency braking, including pedestrian AEB, on new passenger cars and light trucks by September 1, 2029, and NHTSA estimated it would save at least 362 lives a year. The rule's requirements and timing could still change through later rulemaking or court challenges.

FCW and AEB lead to two opposite kinds of complaints. The first is that the system failed to warn or brake before a crash. The second is "phantom braking," where AEB slams on the brakes when nothing is there, which drivers say has caused rear-end collisions and injuries. Owners have filed class actions against several automakers alleging defective collision avoidance systems, and NHTSA has opened investigations into phantom braking complaints. Most such claims seek repairs, refunds, or compensation for lost value, while crash victims bring individual injury claims.

If your car brakes on its own or fails to warn, note the date, speed, and conditions, save any dashcam footage, and report it to the dealer and to NHTSA. See our guide on recalls versus class actions and our technical service bulletin entry.