Automatic Emergency Braking - How It Operates

Automatic Emergency Braking – Do You Know How It Operates?

With AEB being installed in many new vehicles, we must educate ourselves on what it is and how to handle repair.

Any collision-related event I go to these days, the conversation eventually comes around to the recent Texas lawsuit and the judgment against the body shop. How is this affecting you? It definitely makes you think about repairs and the ramifications if they’re done incorrectly.

We all have that gnawing fear of what will happen if a vehicle we’ve repaired gets involved in crash. Will the repairs perform?

Repairs Today

How does this affect how we look at repairs today? We’ve all been reading and hearing about autonomous vehicles and/or ADAS (advanced driver-assistance systems). The autonomous part is where the vehicle’s electronics perform certain functions with little or no input from the driver. Essentially, the vehicle takes control from or adds control to the driver, depending on the level of danger perceived by the vehicle’s sensors. That is the crux of the issue. No matter how you understand a computer, it’s a device that reads inputs and delivers outputs or responses to those inputs. Take the recent lawsuit. A repair may be tested if or when a vehicle is involved in another crash. The electronics are tested in everyday driving. Performing repair procedures as manufacturers require just became a whole lot more important.

The automotive industry is evolving at a pace we’ve never seen. This pace will not slow down. In fact, it may increase. We all have to adapt. How you adapt and process change will be a major factor in the present and future of your shop.

If the sensors are not able to function properly, the system is blind and the vehicle could crash instead of stop or reduce speed.

Understanding all the new features and systems and learning how they apply to everyday driving is important to doing correct repairs. The first step is to realize how important the new features and safety systems are to driving, depending on whether the ADAS is designed to warn or take control of vehicle functions. All components must be operating correctly at completion. The vehicle must be able to recognize the perceived danger and react. Once we all appreciate the levity of the responsibility we have, we can avoid situations such as the one that happened in Texas.

With automatic emergency braking, or AEB, being installed in many new vehicles as part of the ADAS package, this ability to recognize the perceived danger becomes critical to operation. The reality is that if the sensors are not able to function at optimum performance, the system is essentially blind or limited in function. In layman’s terms, the vehicle could crash instead of stop or reduce speed. Let’s evaluate how you would process this feature.

What is AEB?

AEB is exactly what it says – it’s a part of collision warning and avoidance systems as well as pedestrian safety systems. It’s the function that either assists or applies brakes in the event of a potential collision. Sensors such as radar, cameras and/or lidar in conjunction with other inputs such as speed and antilock braking, to name a few, sense parameters required for the vehicle to react.

There are three levels of AEB:

  1. Warning signals such as audible tones, lights on the dash and physical indicators such as steering wheel vibration or seat vibration.
  2. Assistance to brakes to reduce reaction time when the brakes are applied. The brake boost, when applied, increases braking at the first touch of the pedal versus waiting for full-foot pressure to increase braking pressure. This boost gives a quicker reaction time and allows for the reduction of speed or the complete stop of a vehicle much more quickly than conventional systems.
  3. The brakes apply with no input from the driver. Sensors detect danger and apply the brakes as needed.

This is a basic understanding of how this feature works. Now, I would ask yourself some questions. These are not in order of importance but are meant to determine how prepared you are to repair this vehicle:

  • Do I or my staff know how this system operates?
  • Do I or my staff understand its critical function?
  • What needs to be done?
  • Where do I or my staff find information on the repair?
  • How will I document the repair?
  • Do I have all the necessary equipment, or do I need to sublet?
  • How do I conduct a test?

More questions can be added to this list, but you get the idea. Education on all these new components and features is a necessity in today’s world of repair. Assuming that people understand is a luxury we can no longer afford.

If you’re reading this, you have a thirst for knowledge and want to learn more. Most people are that way. This is where the value of training really pays off. Sources such as I-CAR and association events such as local and state meetings, NACE and SEMA are great places to get information. Getting that information to all employees is beneficial to being confident in speaking about repairs and repairing vehicles. Many vehicle owners do not understand how the vehicle works, so your knowledge will also build the customer’s confidence that their vehicle will be repaired properly.

OE Information

To know how to repair these vehicles, we need to be proactive on information. Because it’s critical to perform a repair correctly, following the manufacturer’s procedures is the best way to ensure a correct repair. Assuming and/or guessing on these types of repairs is not a good practice.

The good news is that the instructions are readily available. Simply by visiting the manufacturer’s website, ALLDATA, I-CAR RTS website,, Mitchell or other sites, you can find any of the vehicle manufacturer instructions you’re looking for. We just need to look them up. Estimators and adjustors need to be looking up what other procedures – such as pre-scans, post-scans, recalibrations and reprogramming – are needed after repairs. These are processes that verify that AEB and other features are functional as designed. This information also serves as documentation that the repair was done per the OE recommendations. Following the required steps and documenting the repair should now be a standard procedure.

Whether you buy the equipment needed to perform the proper repair or sublet the job out is a business decision. How you get there is not the issue – we as an industry just need to get there.


I recently attended a seminar at Auto Glass Week in Florida, an event that is attended by many of the auto glass companies across the U.S. ADAS and AEB are great concerns to the auto glass replacement industry. A large portion of windshields now require or will require recalibration after the glass is either R&I’d or replaced, as well as when the camera system is removed from the mounting brackets attached to the glass or vehicle.

Depending on the vehicle manufacturer, the recalibration can be:

  • A static test. Done with target boards in a controlled environment
  • Dynamic. Involves connecting a scan tool and activating a relearn procedure. The vehicle must then be driven up to 70 miles until complete. This is not normal, but it has occurred.
  • Combination of static and dynamic. The recalibration is to ensure that the vehicle can perceive dangers correctly as far as clarity and distance to hit the correct response time.

Sean O’Malley of the Insurance Institute for Highway Safety (IIHS) presented on auto glass replacement and ADAS systems that became relevant to the operation of AEB. He said:

  • They tested a number of factors between aftermarket glass and OE glass and found no difference between the OE glass and aftermarket pieces tested.
  • In issues of failures of system operation, IIHS found the frit or brackets that mount the cameras to the glass to be issues.

There were some other points that were discussed, but the issue of failures made me think a little bit. In the IIHS presentation, it was noted that a bracket that the ADAS camera was mounted to had a degree of twist from OE specs. This variance had a very large impact on system operation. The degree of variance was the difference between the vehicle stopping in time to prevent impact or reduce severity or a collision occurring with the vehicle in front. This study brings to light a lot of issues:

  • Glass R&I and replacement just took a whole new twist. Many or most replacements on vehicles with ADAS may not be able to be done mobile.
  • Equipment such as scan tools and target boards may be needed.
  • Replacing a specific part is no longer the sole reason to see what relearning procedures are required. Certain operations, such as R&I of glass, will also require relearning processes. Even vehicle alignments could be an issue.

As an industry, we need to look at these electronics with a different perspective. When airbags came on the scene, we knew they needed to be there in the event of a crash. We replaced the parts that were damaged, and did a scan to check and clear for codes, released the vehicle and were confident all was operational. Today, ADAS and particularly the AEB is an every-minute-of-driving application with a whole lot more considerations. No longer is a scan enough to complete all operations.

Two Industries, Different Views

With the recent news on faulty repairs and the liability associated with them, glass shops are facing a dilemma. How do they deal with ADAS? When the windshield is replaced, does the recalibration need to be done prior to releasing the vehicle back to the customer? I really hope that body shops take notice of these issues, as many glass operations in shops are also affected by this. Whether you do your own glass or sublet, instructions to complete the repair must be accessed and followed. Here are some of the issues:

  • Mobile service. Will technicians have the equipment and space or proper parameters to do a recalibration, be it static or dynamic?
  • Is the equipment available to do the procedure?
  • Many automakers specify dealer glass vs. aftermarket.
  • The costs associated with equipment and time with training and doing the installation
  • Many dealers will not or do not have the equipment to do a recalibration.
  • Many dealers do not want glass being replaced at their dealerships by glass companies, even if they’re scheduled to have a recalibration done.
  • As to sublet by body shops, how are you going to deal with this procedure?

There is a great deal more to this issue, but you get the idea. There is a whole lot of confusion and chaos currently surrounding this problem. With more than 11 million windshields replaced each year, the problem is staggering.

Some companies are going the route of replacing the glass and having recalibrations done before returning the vehicle to the customer, which requires a lot of time and effort. Some are giving vehicle owners waivers to give to dealers. The owner would then schedule and take their vehicle to their company of choice to get the recalibration done. There are many other options, but the point is, nobody knows the best solution. With this type of confusion, we all face some interesting exposure to complications of safety systems not functioning properly. How you and your shop addresses this is your decision. I wish I had answers for you, but I’m just a technical person. Offering advice on what to do, besides following the vehicle manufacturer instructions, is not my place. My job is to make you understand how these features work and how they’re completed for repair.


As the events and changes unfold and the solutions become available, I’ll do my best to offer as much information as I can. The ultimate decisions are yours, and I’m hoping you choose to keep learning more about all the new features and ramifications of new-vehicle repairs. The questions are, how are you looking at repairs in your shop today, do you now what you need to know, and what do you need to do?

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