Forward Collision Warning (FCW)
Forward collision warning (FCW) alerts the driver when the vehicle detects a rapidly developing risk of hitting a vehicle or other supported object ahead. Depending on the design, it may use a forward camera, radar, or both to estimate distance, relative speed, and time to a possible collision.
What it does
FCW typically gives a visual, audible, or haptic warning so the driver can brake or steer. It is a warning function: by itself, it does not apply the brakes. Automatic emergency braking is a separate intervention feature, although manufacturers often package the two together.
Detection range and supported targets vary. Weather, dirt, glare, curves, unusual vehicles, and a large speed difference can reduce performance. A warning may arrive late, fail to appear, or be triggered when the driver does not perceive a danger. The driver must continue watching the road and be ready to brake.
For sensing, risk calculation, and the relationship with automatic braking, see forward collision warning technology.