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ADAS Under the Hood: Autonomous Emergency Braking

November 11, 2024

LD Warning

As vehicle safety systems have become increasingly sophisticated, brakes have emerged as one of the most critical features in modern cars.

Major automakers have, as a result, committed to have at least 95% of their light-duty vehicles equipped with Autonomous Emergency Braking (sometimes referred to as automatic braking systems or AEB).

But here's what many shop owners don't realize: every windshield replacement, bumper repair, or alignment adjustment could affect these systems' performance.

And when these systems don't work correctly, it's not just an inconvenience?it's a safety issue that brings customers straight to your door.

In this guide, you?ll find everything you need to know about AEB: how it works, why proper calibration matters, and most importantly, how your shop can tap into this growing market.

Do Autonomous Emergency Braking (AEB) Systems Work?

In a word, yes.

Countless reports have found that automatic braking alone reduces rear-end crash rates for passenger vehicles by 50% and rear-end injury crash rates by 56%.

Similarly, for pickup trucks, AEB lowers the rate of rear-end crashes by 43% and rear-end injury crashes by 42%. Finally, in large trucks, AEB was found to have a 34% reduction in the risk of rear-end collisions.

With such dramatic reductions in crash rates across vehicle types, understanding how an autonomous emergency braking system achieves these results is essential knowledge for any shop owner looking to service these increasingly common safety systems.

How Does An AEB System Work?

Cars today are frankly masterpieces of integrated technology. There are so many systems working tirelessly behind the scenes to prevent collisions. Automatic emergency braking systems are amongst them and rely on three main components:

  1. Sensors: Typically a combination of radar, cameras, and in some high-end vehicles, LiDAR technology
  2. Control module: The control center that processes sensor data and makes split-second decisions
  3. Brake actuator: The mechanism that physically applies the brakes when needed

What makes automatic braking systems truly remarkable is how it combines these sensors into a layered response to potential dangers.

AEB systems end up operating in a few different types of scenarios, including:

  • Forward Collision Warning (FCW) is a fundamental component of AEB systems. FCW alerts the driver to imminent dangers, often providing a small but crucial window for them to intervene before the AEB system takes over.
  • Next comes Dynamic Brake Support (DBS), which assists drivers by increasing brake force if the AEB system senses the driver is braking but not with enough intensity to avoid a collision.
  • The worst case scenario is Crash Imminent Braking (CIB) which will automatically apply full braking power if the driver fails to react in time.

Each feature and sensor works together as part of a sequence that prioritizes warning the driver and only steps in to actively brake as a last resort.

The biggest difference these systems make lie in how quick everything happens. From detection to full braking, the entire event takes place in the course of fractions of a second, far faster than human reflexes could manage.

This fact alone is why including an automatic emergency braking system has become such a critical safety feature, and why proper calibration is essential for your customers' safety.

What Kind of AEB Systems are There?

AEB systems fall under the category of ADAS (Advanced Driver Assistance Systems). They are the various automatic safety features that help drivers navigate and avoid accidents.

There are countless specialized systems and subsystems under the umbrella of ADAS, nevermind just AEB. Far too many for a single technician to know.

However, the following core types will cover most vehicles entering your shop.

City safety systems (Low-speed AEB)

Easily the most common type of autonomous emergency braking system. These serve as the frontline defense against one of the most frequent types of collisions: rear-end crashes in urban environments. In cities, vehicles frequently stop and start in heavy traffic.

This AEB system constantly monitors the space between your car and the vehicle ahead, ready to intervene when it detects a potential collision. Given that most rear-end collisions occur at speeds below 55 mph, this system has become the standard required by NHTSA, proving its effectiveness with a 50% reduction in rear-end crashes for passenger vehicles.

Highway systems (High-speed AEB)

Operating at speeds exceeding 55 mph means collision risks become significantly more severe. These systems employ long-range radar that can scan hundreds of meters ahead, giving vehicles more time to respond at higher speeds. Often working in tandem with adaptive cruise control, highway AEB systems require precise calibration to ensure split-second timing and accurate distance measurements between other passenger cars.

Pedestrian and cyclist detection systems

This category represents the most sophisticated tier of AEB system car technology, using advanced algorithms to distinguish humans from other objects on the road. This feature relies on technology from multiple sensors and high-resolution cameras to create a detailed picture of the environment, making proper calibration absolutely critical.

Specialized AEB variations

Manufacturers have also developed specialized variations to address more specific safety scenarios. For instance, rear emergency brakes are specifically intended to prevent collisions while the vehicle is in reverse. These ADAS systems can reduce incidents of this type by 78%.

Other advanced autonomous emergency braking features include:

  • Intersection AEB for cross-traffic detection
  • Large animal detection for rural areas
  • Low-light systems with enhanced sensors
  • Multi-collision brake systems
  • Evasive steering support systems

Each of these specialized systems requires its own unique calibration procedures, adding another layer of complexity to modern vehicle servicing.

System Limitations

Understanding the limitations of autonomous emergency braking helps shops provide better service:

  • Weather Conditions: Heavy rain or snow can affect sensor performance
  • Lighting Changes: Sudden bright light or darkness can impact camera systems
  • Road Conditions: Steep hills or sharp curves may reduce system effectiveness
  • Speed Ranges: Different AEB systems have specific operational speed limits

AEB vs. Brake Assist: Understanding the Difference

One of the most common misconceptions repair shops encounter involves the difference between an autonomous emergency braking system and traditional brake assist. While both systems enhance vehicle safety, they function in fundamentally different ways.

How brake assist works

Traditional brake assist is essentially a power-boost system that enhances driver input.

When a driver slams on the brakes in an emergency, brake assist detects the sudden pedal pressure and maximizes braking power. It's a reactive system that depends entirely on driver action. If the driver doesn't hit the brakes, brake assist won't engage.

How AEB works

In contrast, the automatic braking systems operate independently of driver input. Using a complex network of sensors and processing systems, it actively monitors the environment and can initiate braking without any driver intervention. When the autonomous emergency braking detects an imminent collision, it can apply the brakes automatically, even if the driver hasn't touched the brake pedal.

Working together

These systems aren?t an either/or situation. They complement each other. For example, if a driver responds to an AEB warning by hitting the brakes, but not hard enough, both systems will engage:

  • AEB provides the initial warning and begins brake preparation
  • Brake assist amplifies the driver's braking effort
  • AEB can still step in with additional braking if needed

For your shop, understanding this relationship is crucial.

When customers report braking issues, knowing whether the problem lies with the automatic braking system or traditional brake assist will determine your diagnostic and calibration approach.

Common Calibrations Needed for AEB Systems

For repair shops, understanding when to conduct an ADAS calibration is just as important as knowing how to perform the calibration itself.

Even minor repairs can affect these sophisticated systems, potentially compromising their life-saving capabilities. The AEB system requires calibration in several common scenarios:

Windshield Replacement or Repair

Ever wear a pair of glasses or sunglasses with a smudge on the front that makes it hard to see? This is the exact situation that forward-facing cameras can face for autonomous emergency braking systems. Whenever windshields are repaired or replaced, these cameras must be calibrated to make sure these critical sensors are working properly.

Front-End Repairs

Radar sensors embedded in bumpers mean that any repair or replacement of this component necessitates a calibration. Subtle changes to grille structure can affect sensor performance. These sensors are so sensitive that even a change in paint thickness on repaired bumpers can influence functionality and require recalibration.

Suspension Work

Modifications to a vehicle's suspension creates a cascade of effects on autonomous emergency braking performance. Changes in ride height alter the angles of multiple sensors, while alignment adjustments can impact the system's ability to accurately detect obstacles. The entire detection zone geometry must be recalibrated to account for any changes in suspension configuration.

Wheel Alignment

Proper wheel alignment is crucial for AEB system car performance beyond just tire wear and handling. Similar to ride height, any alignment changes might throw off how the system is perceiving distances.

The Future of AEB

NHTSA requirements announced in May 2024 make automatic emergency braking standard on new vehicles, but this is just the beginning. Between legislation and technological improvement, there are multiple factors driving the evolution of automatic emergency braking.

Next-generation systems will feature advanced multi-modal sensors, incorporating high-resolution cameras, sophisticated radar, and more affordable LiDAR technology. Artificial intelligence will drive improvements in object recognition and prediction for both forward collision warning. Vehicle-to-vehicle communication will enable coordinated responses to potential accidents, increasing overall highway safety.

For repair shops, this progression means calibration procedures will become more complex but also more crucial in knowing how to deal with any given advanced driver assistance system.

AEB Calibration with RevvADAS

There are dozens upon dozens of different AEB and other ADAS systems on the market, each requiring unique calibration procedures and OEM specifications.

What could be a lucrative revenue stream often becomes a frustrating maze of research and verification. While ADAS calibration services can add significant profit to your bottom line?potentially $1,250 per job?the time spent identifying specific systems, hunting down correct procedures, and verifying calibration requirements can eat away at those margins.

With RevvADAS, you can transform this complexity into a profitable service offering. Our AI-powered platform helps you:

  • Generate comprehensive calibration reports instantly
  • Identify every billable ADAS procedure
  • Access detailed OEM specifications and requirements
  • Save hours of research time per repair
  • Protect your business with proper documentation

Schedule a personalized demo today and discover how RevvADAS can help you turn ADAS calibrations into a major profit center for your business.

Author: Revv Editorial
Author: Bryan Grover