Automatic emergency braking systems are designed to first warn you of an impending frontal collision, then automatically apply the brakes if you don’t — or if you don’t apply them hard enough. While this may not happen in time to completely avoid an accident, particularly on slippery roads, any reduction in speed will reduce the force of impact.
Many recent systems also include pedestrian detection, and some add cyclist detection. These systems can “see” to the sides, and if they determine an object approaching is a person walking or riding a bicycle, they give a warning and apply the brakes if you don’t.
How Do They Work?
To perform these functions, your vehicle determines the distance to an approaching object, then decides if you’re closing too quickly to avoid an accident. To determine the distance to an object ahead, automatic emergency braking typically relies on radar, cameras or a combination of the two. Pedestrian and cyclist detection usually use cameras, with their images being interpreted by a computer.
Why Automatic Emergency Braking Is So Valuable
A recent study by the National Highway Traffic Safety Administration divided all vehicle crashes into 21 categories (such as rear end, head on, rollover and hitting a pedestrian, animal or tree), and by far the largest percentage — nearly a third of the total — was attributed to rear-end collisions. This would be where one vehicle plows into the vehicle ahead, which is exactly what automatic emergency braking is intended to address.
Although the term “automatic emergency braking” is fairly new, the concept dates back a ways. It was often previously referred to as forward collision warning and mitigation, but that wasn’t universally used, and it may have been a little confusing — as “mitigation” wasn’t necessarily translated to, “can apply the brakes itself if you don’t,” which is what it was supposed to mean.
Forward collision warning systems began appearing on higher-priced cars in the mid-2000s, with mitigation capabilities being added shortly thereafter. As with many high-tech features, these systems became more widespread over the ensuing years, and they’re offered on most new vehicles today.
Not All Systems Are Created Equal
It’s important to note that not all automatic emergency braking systems are alike. Not only can they differ among manufacturers, they even differ among individual models in a manufacturer’s lineup. For instance, some may include pedestrian detection and perhaps cyclist detection, while others may not, and some might only work at city-driving speeds.
Furthermore, the threshold at which they activate can differ. Some drivers may feel the warning given (which can be startling) comes on too early, whereas they may not feel that way in a different vehicle; it all depends on how the vehicle has been programmed.
Smart, But Not Foolproof
Regardless of manufacturer, automatic emergency braking (as well as pedestrian and cyclist detection, and other high-tech safety features) relies on sensors that may not work under certain conditions, such as during inclement weather. Thus, they are not 100% reliable, and should never be counted on to replace good ol’ fashioned driver awareness.
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