A collision warning system (also known as pre-collision system, collision avoidance system, forward collision warning system or collision mitigating system) is an automobile safety system designed to reduce the severity of an accident. It uses radar (all-weather) and sometimes laser and camera (both sensor types are ineffective during bad weather) to detect an imminent crash.
Once the detection is done, these systems either provide a warning to the driver when there is an imminent collision or take action autonomously without any driver input (by braking or steering or both). Pre-collision system by braking is appropriate at low vehicle speeds (below 50km/h), while pre-collision avoidance by steering is appropriate at higher vehicle speeds. Cars with collision warning system are also equipped with adaptive cruise control.
Pre-collision system is the radar-based system that uses a forward-facing millimeter-wave radar. When the system determines that a frontal collision is unavoidable, it preemptively tightens the seat belts, removing any slack, and pre-charges the brakes using brake assist to give the driver maximum stopping power instantly when the driver depresses the brake pedal.
A CCD camera on the steering column monitors the driver’s face to determine where the driver is looking. If the driver’s head turns away from road and a frontal obstacle is detected, the system will alert the driver using a buzzer, and if necessary, pre-charge the brakes and tighten the safety belts.
Updated driver monitoring system detects whether the driver’s eyes are properly open. It monitors the driver’s eyes to detect the driver’s level of wakefulness. This system is designed to work even if the driver is wearing sunglasses, and at night.
Driver monitoring system includes a rearward-facing millimeter-wave radar mounted in the rear bumper. This system adjusts the active head restraints by moving them upward and forward to reduce the risk of whiplash injuries if an imminent rear collision is detected.
Advanced pre-collision system has a twin-lens stereo camera located on the windshield and a more sensitive radar to detect “soft” objects such as animals and pedestrians. A near-infrared projector located in the headlights allows the system to work at night. With the adaptive variable suspension and electric power steering, the system can change the shock absorber firmness, steering gear ratios, and torque assist to aid the driver’s evasive steering measures. The lane departure warning system will make automatic steering adjustments to help ensure that the vehicle maintains its lane in case the driver fails to react.
Collision warning system with GPS-navigation is designed to determine if the driver is late in decelerating at an approaching stop sign, will then sound an alert and can also pre-charge the brakes to provide optimum braking force if deemed necessary.
The further advanced pre-collision systems have additional a front-side millimeter-wave radar to detect potential side collisions primarily at intersections or when another vehicle crosses the center line. The latest version tilts the rear seat upward, placing the passenger in a more ideal crash position if it detects a front or rear impact.
Higher speed collision warning systems enable deceleration of up to 60kmh (37mph) as compared to the current generation system of 40kmh (25mph). This higher speed system uses the same technologies with the increased braking force up to twice that applied by average drivers.
Pre-Collision System with Pedestrian-avoidance Steer Assist and Steering Bypass Assist can help prevent collisions in cases where automatic braking alone is not sufficient, such as when the vehicle is travelling too fast or a pedestrian suddenly steps into the vehicle’s path. An on-board sensor detects pedestrians and issues a visual alert on the dashboard immediately in front of the driver if the system determines that there is a risk of collision. If the likelihood of a collision increases, the system issues an audio and visual alarm to encourage the driver to take evasive action, and the increased pre-collision braking force and automatic braking functions are activated. If the system determines that a collision cannot be avoided by braking alone and there is sufficient room for avoidance, steer assist is activated to steer the vehicle away from the pedestrian.