Driver-assistance systems called collision avoidance systems, sometimes known as crash avoidance systems, use sensors and algorithms to identify possible hazards or obstructions and issue alerts to the driver to help prevent a collision. A collision avoidance system is a type of safety device used to alert, warn, or help drivers avoid impending crashes and lower the likelihood of accidents. The technologies and sensors used by collision avoidance systems include ultrasonic sensors, alarm, cameras, GPS, and artificial intelligence. Several collision avoidance systems work differently to help drivers avoid collisions and reduce risk. Some systems alert or warn the driver, while others take control and override them.

To prevent rear-end crashes, a system keeps track of your car's speed, the speed of the car in front of you, and the separation between the two vehicles. If vehicles approach too closely, the forward collision warning system will alert the driver.

When a car detects an object approaching, a technology automatically applies the brakes. Some automatic emergency braking systems simply apply a modest amount of braking force, giving the driver enough time to intervene and take control.