The brake is essential to the safety of vehicles. Yet, with drivers distracted by texts and apps, they’re not always applied when they should be. In fact, about one out of every four car crashes are rear-end collisions, often caused by a driver who doesn’t brake in time. To minimize these types of car accidents, automobile companies introduced autonomous or automatic emergency braking (AEB).

AEB systems combine sensors and brake controls to help prevent high-speed collisions when humans fail to respond quick enough in dangerous situations. Some of these systems can prevent collisions altogether by braking fully, but most are designed to simply reduce the speed of a car before it hits something.

According to reports from the National Transportation Safety Board, the installation of AEB technology in cars will effectively reduce 80 percent of the rear-end collision, which results in 1,700 deaths and half a million injury every year.

Related: Uber’s Self-Driving Crash Proves, Once Again, Human Drivers Suck

Types of Automatic Emergency Braking Systems

AEB technology can be segmented into three different systems.

Forward collision warning (FCW). This was the first automatic emergency braking technology available in cars. While FCW doesn’t actually brake for a driver, it does provide a visual, audible or tactile alert that a collision with a car or other object is possible. Data shows that FCW technology rear-end accidents by 27 percent. Dynamic Brake Support (DBS). Like FCW, DBS technology first provides a warning to alert the driver if it senses a chance of collision. But if the driver doesn’t hit the brakes hard enough, DBS will provide the extra muscle. It can supplement the driver’s braking – providing additional force that can help to prevent the collision. Crash Imminent Braking (CIB). CIB is the most autonomous of the three. If a driver fails to respond to a crash alert warning and doesn’t apply the brakes, CIB kicks in and provides full braking force automatically to avoid a collision.

Related: Driverless Car Accidents and the Trolley Problem

Multi-Manufacture Agreement Drives AEB market

Consumers have wanted these systems for some time now. According to a nationwide survey conducted by Consumer Reports, forward-collision warning and automatic emergency braking were on the top of the list as systems consumers desired on their next vehicle.

And thanks to an agreement among the National Highway Traffic Safety Administration (NHTSA), the Insurance Institute for Highway Safety (IIHS) and 20 major automakers they’ll soon get it.

The pact: Equip nearly every passenger vehicle sold in the U.S. with standard forward collision warning and automatic emergency braking systems by 2022. Only some passenger cars with manual transmission and some heavy duty pickups and SUVs will be slated for a later date. Some “exotic” cars are also excluded from the directive. But all told, about 99 percent of the cars will fall under this agreement.

While six years may seem like a long time, the list of cars with AEB technology as standard equipment doubled in the past year. And the list continues to grow. Nearly all vehicles in the Mercedes lineup feature AEB technology as standard equipment as of this year. Nissan announced that it will have AEB onboard every 2018 car it sells in the U.S. And Tesla included AEB technology in their last Autopilot update.

Of course, it’s important to remember that these advancements are enhancements, not replacements for staying vigilant while driving.

Yatin Kumar is a content marketer who works at Autoportal . His passion is to write about new and trending vehicles.