When you’re driving, unexpected hazards can appear in an instant. The Honda Collision Mitigation Braking System (CMBS) is designed to be an extra set of eyes, helping you avoid or reduce the impact of a frontal collision. This advanced safety feature is a key part of Honda’s commitment to protecting everyone on the road.
Let’s look at how this system works, what it feels like when it activates, and how you can use it with confidence.
Honda Collision Mitigation Braking System (CMBS)
CMBS is not a single part, but a sophisticated network of sensors and computers. It’s classified as an Advanced Driver-Assistance System (ADAS). The primary goal is to detect potential frontal collisions with vehicles, pedestrians, and even cyclists, and then take action if you don’t.
It’s important to understand that CMBS is a mitigation system. It’s not designed to drive the car for you or prevent all accidents. Instead, it steps in when a collision seems highly likely, aiming to lessen the severity.
How Does Honda CMBS Actually Work?
The system uses a combination of radar and a camera. The radar, typically located behind the Honda emblem in the grille, detects the distance and speed of objects ahead. The camera, mounted near the rearview mirror, helps identify what those objects are—like a car, a person, or a bike.
By fusing this data, the car’s computer constantly assesses the risk. It operates in three main stages to get your attention and, if needed, intervene.
The Three-Stage Warning and Intervention Process
CMBS is designed to escalate its response based on the level of danger. Here’s the typical sequence:
- Visual and Audible Warnings: First, the system detects a potential collision risk. You’ll see flashing visual alerts in your instrument cluster, often accompanied by a message like “BRAKE.” At the same time, you’ll hear an audible beep. This is your cue to take action.
- Light Brake Application and Seatbelt Tug: If the system determines you haven’t reacted sufficiently, it moves to stage two. It will apply light braking force on its own. You might also feel the Electric Power Steering (EPS) provide slight vibration or resistance. Additionally, the front seatbelts may tighten repeatedly in a tugging motion to physically alert you.
- Strong Automatic Braking: In the final stage, if a collision is now imminent and you still haven’t braked, CMBS will apply strong automatic braking. It will try to reduce your speed as much as possible to either avoid the crash entirely or dramatically reduce the impact energy.
What Can Honda CMBS Detect?
The system is programmed to recognize specific types of hazards. Its capabilities have improved over different model years, but generally include:
- Other Vehicles: This is its primary function. It monitors cars, trucks, and motorcycles traveling in the same direction.
- Pedestrians: The camera helps identify human shapes, both during the day and, in newer models, at night.
- Cyclists: Many newer Honda models can also detect cyclists in your path, day or night.
It’s crucial to check your owner’s manual for your specific model year, as detection abilities vary. For example, early systems may only work for vehicles, while newer ones are more comprehensive.
What It Feels Like When CMBS Activates
If you’ve never experienced it, an CMBS activation can be startling. The initial beep and light are familiar, but the automatic braking is more intense. You’ll hear a rapid, loud grinding or buzzing sound from the brake actuator. The brakes will apply firm pressure, sometimes bringing the car to a complete stop.
Your instinct might be to fight the steering or release the brake. It’s best to let the system work and keep your hands on the wheel. The system will deactivate once the threat is gone or you take firm control.
Limitations and Important Driver Responsibilities
No safety system is perfect. CMBS has specific conditions where its performance is limited or it may not work at all. You, the driver, are always ultimately responsible for safe operation.
- Weather: Heavy rain, fog, snow, or ice can block the radar and camera sensors.
- Sensor Obstruction: A dirty windshield (in front of the camera) or a grille covered in snow/mud will impair function.
- Certain Road Conditions: Sharp curves, steep hills, or very poor road markings can confuse the system.
- Specific Scenarios: It may not react to crossing traffic, oncoming vehicles, or stationary objects like trees or walls in some models. It also may not detect a pedestrian or cyclist who is lying down or is very short.
- System Malfunction: If there’s an issue, a message like “CMBS Problem” or “Radar Obstructed” will appear on your multi-information display.
How to Use and Adjust Your CMBS Settings
You have some control over how CMBS behaves. You can usually adjust the warning timing and turn the system on or off.
- Accessing Settings: Use the steering wheel controls to navigate to the vehicle settings menu on your instrument cluster display.
- Adjusting Warning Timing: You can often choose between “Long,” “Normal,” and “Short” for when warnings begin. “Long” gives you the earliest alerts.
- Turning CMBS On/Off: You can deactivate the system. A indicator light will appear on the dash to show it’s off. Remember, it usually resets to “ON” every time you start the car.
Why would you turn it off? Some drivers do in very slow, congested traffic where frequent close-quarters driving might cause false alarms. However, Honda recommends keeping it on at all times for maximum protection.
Differences Between CMBS and Other Honda Safety Tech
CMBS is part of a suite of features often bundled under names like Honda Sensing®. It’s easy to confuse them.
- CMBS vs. Forward Collision Warning (FCW): FCW is just the first stage—the visual and audible alerts. CMBS includes FCW but adds the automatic braking intervention.
- CMBS vs. Adaptive Cruise Control (ACC): ACC uses the same radar to maintain a set following distance and can slow the car down. However, ACC is for convenience during cruising. CMBS is for emergency collision avoidance and works even when ACC is not engaged.
- CMBS vs. Lane Keeping Assist (LKAS): These are completely different. LKAS helps you stay centered in your lane using the camera. It does not brake for obstacles.
Maintenance and Servicing Your CMBS
Because CMBS relies on precise sensors, proper maintenance is key. If you need repairs, especially to the front end or windshield, special calibration is required.
- Windshield Replacement: If your windshield is replaced, the camera behind the mirror must be recalibrated. Always use a certified glass shop familiar with Honda ADAS systems.
- Front-End Repair: After a bumper or grille repair, the radar sensor may need recalibration to ensure its aiming is perfect.
- Regular Cleaning: Keep the area of the windshield in front of the camera clean and clear of stickers or obstructions. Gently clean the Honda emblem/grille area where the radar sits.
Ignoring this can lead to the system being partially or fully inoperative, without you even realizing it.
Common Questions and Misconceptions
Let’s clear up some frequent points of confusion about this system.
- “It braked for no reason!” (False Alarm): Sometimes, CMBS might interpret a sharp shadow, a metal bridge joint, or a vehicle quickly cutting in and out of your lane as a threat. While rare, it can happen. This is why driver awareness is still paramount.
- “I can rely on it to brake for me always”: This is a dangerous assumption. You should always drive as if the system isn’t there, using it only as a backup safety net.
- “It will work at very high speeds”: There are limits to how much speed it can reduce. A high-speed closing scenario may still result in a collision, albeit at a lower speed.
FAQs About Honda’s Collision Braking Technology
Q: Can I permanently turn off the Honda Collision Mitigation Braking System?
A: No, it will default to “ON” each time you start your vehicle. You must manually turn it off each trip if you choose to.
Q: Does CMBS work if I’m pressing the accelerator?
A: Yes. If the system determines a collision is imminent, it will override accelerator input and apply the brakes. You will feel the car resisting your acceleration.
Q: Will CMBS prevent all rear-end collisions?
A: No. It is designed to mitigate, not prevent. Its effectiveness depends on speed, conditions, and the specific scenario. Some collisions may still occur.
Q: My car stopped automatically in traffic. Is that normal?
A: Yes, if the car ahead stopped suddenly and you did not react, CMBS can apply the brakes and bring your vehicle to a full stop to avoid a crash.
Q: What does the amber CMBS indicator light mean?
A: A solid amber light typically means the system is turned off. A flashing or steady amber light with a message usually indicates a problem or sensor obstruction that needs checking.
Q: Is Honda CMBS the same on all models?
A: The core function is similar, but detection range, capabilities (like night pedestrian detection), and sensitivity improve with newer model years. Always refer to your specific owner’s manual.
Final Thoughts on Driving with CMBS
The Honda Collision Mitigation Braking System is a remarkable piece of safety technology that acts as a vigilant co-pilot. It’s there for those split-second moments when human reaction time might fall short. By understanding how it works, its limitations, and your role as the driver, you can create a safer driving environment for everyone.
Remember, no advance system replaces attentive, defensive driving. Use CMBS as the powerful safety tool it is, but always keep your eyes on the road and your hands on the wheel. Your awareness combined with Honda’s technology is the ultimate safety package.