How Well Do Automatic Braking Systems Work?

A lot of people heard me talking about the automatic braking system on the new 2019 Subaru Ascent I reviewed last week, and that prompted a lot of questions. The big question is, like all technology in vehicles, how well does it work?

Although some folks are skeptical about new features on vehicles, the government and automakers have agreed that all vehicles by 2022 will have this safety feature, so Americans are going to have to get used to this technology. Today, roughly 10% of cars on the road have automatic braking. It is probably a good idea that all vehicles will have this technology in the next five years since one-third of all crashes are rear-end collisions.

In years past, I've reviewed many luxury vehicles with automatic braking, but today this feature is available on mainstream cars like Hyundai Elantra, Mazda CX-3, Kia Forte, and Jeep Renegade, but it is optional and at an extra charge for now.

So, how does it work? The answer depends on the particular vehicle. Some are supposed to come to a complete stop by itself, other systems are designed to slow the vehicle down to lessen the damage. It is important to understand and ask questions if you are considering a car today with automatic braking. You do not want to come to rely on your car braking itself, most systems still take driver interaction to completely avoid a crash.

AAA Study Findings: AAA has studied and tested the automatic braking systems, and they came to the following conclusions:

• The systems designed to completely stop the vehicle reduced speeds by twice that of the systems that are intended to slow the vehicle before impact.
• The systems designed to just slow down the impact were able to avoid crashes completely in about one-third of the vehicles tested.
• In testing of vehicles traveling at 45 miles per hour going toward a parked vehicle, the systems designed to stop completely reduced speeds by 74 percent, and successfully stopped 40 percent of the time. The systems designed to lessen crash damage were only able to reduce speed by 9 percent.

Translated, the AAA study shows that in most cases this technology still has a ways to go, which is why you do not want to rely on the systems wholly. For me, the perfect combination today is automatic emergency braking combined with forward collision warning. Forward collision warning gives you a loud warning you are approaching a fixed object or coming up on something too fast. Some of these warnings also throw a red light on the windshield. I’ve driven a lot of vehicles with the collision warning, and trust me, you will hit the brakes hard.

Automatic Braking Can Be A Big Help. Another interesting fact from a study by the Automobile Club of Southern California’s Automotive Research Center found that when traveling under 30 miles per hour, a speed reduction of 10 miles per hour will reduce the crash impact energy by 50 percent, and that is significant for those who drive in town and also in stop and go traffic. Not only will this save injuries, it will cut down on collision costs.

Preparing For Autonomous Vehicles. Perfecting systems like automatic emergency braking is intended to put us one step closer to autonomous driving. The same is true of adaptive cruise control and lane keeping assist which puts you back in your lane should you stray out of it. Adaptive cruise control is also a big step toward self-driving vehicles. This cruise control system keeps you the same distance from the car ahead of you. If that car slows down, your car brakes. If it speeds up, your car will increase to the predetermined speed set by the driver.

Be Cautious, Ask Questions. Bear in mind, the auto marketing folks at the automakers always make new features sound like the greatest thing since sliced bread. This is why it is so important to ask dealership personnel exactly how the braking system is designed to operate, then as always, keep your eyes on the road and be aware of your surroundings.

Photo Credit: Nissan.