Forward collision warnings (FCW) systems are forward-looking, radar-based systems comprised of collision warning and adaptive cruise control (ACC) with active braking. Forward collision warning systems provide audible and/or visual warnings of vehicles or objects that come within a predefined distance in the front of a vehicle with the system. A radar sensor mounted on the front bumper of the vehicle transmits and receives high frequency radio signals to determine the distance and speed of a target vehicle or object in front of it. Some systems are capable of detecting multiple moving objects at distances up to 500 feet away.
When a commercial motor vehicle equipped with this system approaches a slower moving vehicle, a series of progressively urgent warnings are issued from the system according to pre-set thresholds. These warnings are designed to allow the driver adequate time to decelerate the vehicle and adjust driving behavior.
The ACC component of collision mitigation systems supplements the normal vehicle cruise control by automatically attempting to maintain a safe following interval between the vehicle with the system and a vehicle in front of it. ACC interacts with the commercial vehicle's engine management system (transmission and throttle) and brake control system to adjust the speed of the vehicle when necessary.
Studies have shown that more deaths occur from rear-end crashes than any other kind. The Insurance Institute for Highway Safety (IIHS) has estimated that the Forward Collision Warning function with Automatic Braking alone could help prevent or minimize the damage in approximately 2,268,000 accidents every year in the US, 7,166 of which are fatal.
The cost of a forward collision warning system is approximately $2,500 over the costs of anti-lock braking systems and stability control systems, but the price can vary depending on the number of units acquired. Forward collision warning systems are available on some original equipment models and can be installed by aftermarket manufacturers as well.