Passive vs. Active ADAS Safety Systems

Passive vs. Active ADAS Safety Systems

There are two main types of ADAS that are revolutionizing the automotive industry. Passive ADAS, also known as passive safety systems, and active ADAS, also known as active safety systems. Both of these systems work together to prevent or minimize the chance of accidents, but they differ in their approach. Below, we’ll explain the differences between passive and active ADAS systems and why they are equally important in road safety.

What are the Differences Between Active and Passive ADAS?

Active Advanced Driver Assistance Systems (ADAS), as the name implies, are proactive in their approach to ensuring road safety. These systems are equipped with advanced sensors and advanced computer algorithms that continuously monitor the vehicle’s surroundings and assess potential risks. They can actively intervene when necessary, taking control of the vehicle to prevent accidents.

On the other hand, passive ADAS systems are designed to alert the driver to potential dangers without directly taking control of the vehicle. These systems use sensors and cameras to detect potential hazards and provide warnings and alerts to the driver. By doing so, they empower the driver to take corrective action and make informed decisions on the road.

While both active and passive ADAS systems aim to enhance safety, the fundamental difference lies in the level of intervention. Active systems have the ability to control the vehicle directly, making autonomous adjustments to ensure safety. Passive systems, on the other hand, rely on the driver’s response to the alerts and warnings provided.

Examples of Passive Safety Systems

Passive safety systems use different modes of communication to alert the driver of potential risks. They are designed to quickly capture the driver’s attention and the urgency of the situation. The alerts can take the form of auditory, visual, or haptic feedback.

  • Auditory alerts: These are sound signals that trigger when the system detects a potential danger. For example, a beeping sound may indicate that the vehicle is too close to an object while reversing.
  • Visual alerts: These are warning lights or symbols that appear on the vehicle’s dashboard or head-up display. For example, a flashing light might indicate the car drifting out of its lane.
  • Haptic feedback: This involves physical signals such as vibration in the steering wheel or driver’s seat. This type of alert is especially useful when the visual and auditory warnings might go unnoticed, such as in heavy traffic or loud interior noise situations.

These types of alerts, either used alone or in combination, ensure that the driver is alerted to any potential hazards, allowing them to act and prevent accidents. However, it must be noted that these passive safety systems still rely on the driver’s response and capability to react appropriately. Here are some examples of passive ADAS systems.

Lane Departure Warning (LDW):

One common example of a passive ADAS is the Lane Departure Warning System (LDWS). This system monitors the vehicle’s position within its lane and alerts the driver if it detects unintentional drifting, potentially preventing collisions caused by fatigue or distraction.

Forward Collision Warning (FCW):

Another example is the Forward Collision Warning (FCW) system. This system uses sensors (like cameras, radar, or lidar) to check if the vehicle is getting too close to another vehicle or obstacle. If it senses a possible collision, it will notify the driver to take evasive action.

Blind Spot Monitoring (BSM):

Blind Spot Monitoring (BSM) is another passive system that assists drivers on the road. It uses sensors and radar to monitor the areas not visible in the rear-view and side mirrors and warns the driver if any vehicles are detected in these blind spots when changing lanes.

While not intervening directly, these passive ADAS help drivers make safer and more informed decisions. By providing additional information about the vehicle’s surroundings, these systems can reduce the risk of accidents caused by human error.

Examples of Active Systems

Active safety systems, unlike passive systems, take it one step further by not only detecting potential dangers but also taking action to prevent an accident. With sensors and cameras, these systems can detect hazards, assess risks, and control the vehicle to prevent or mitigate a collision. Let’s take a look at some examples of active ADAS systems.

Automatic Emergency Braking

Automatic Emergency Braking (AEB) is an active safety system that uses sensors and cameras to monitor the road ahead for potential collisions. If the driver does not respond in time, AEB can automatically apply the brakes to stop or reduce the severity of a potential crash. This system can detect pedestrians, cyclists, and other vehicles.

Lane Keeping Assist

Lane Keeping Assist (LKA) is another active system. LKA can detect when a driver unintentionally drifts and can gently steer the vehicle back into its lane using either the brakes or steering assist. This system can help prevent accidents caused by drowsy or distracted driving.

Adaptive Cruise Control

The Adaptive Cruise Control (ACC) system can maintain a selected cruise control speed but also adjust it to keep a safe distance from the vehicle ahead. If the system detects a slower-moving vehicle in front, it will slow down the car to maintain a safe distance and then return to the selected speed once the road is clear.

As these systems continue to evolve, they have the potential to greatly reduce the number of collisions on our roads. However, it’s important to stay alert and attentive while behind the wheel, even when utilizing these advanced safety features.

How do Active and Passive Systems Work Together?

Active and passive systems in some modern vehicles work together to ensure maximum safety and an improved overall driving experience. For instance, if a pedestrian suddenly crosses the vehicle’s path or there is a sudden deceleration of the car in front, the FCW system will alert the driver. But what if the driver fails to react in time? This is when active systems come into play.

In this situation, an active system like the Automatic Emergency Braking (AEB) system kicks in. It doesn’t just raise an alarm, but rather, it takes control of the vehicle and applies the brakes automatically to potentially save lives. Similarly, suppose the driver overlooks the warning from the Lane Departure Warning System (LDWS) and continues to drift from the lane. In that case, the Lane Keeping Assist (LKA) will automatically correct the vehicle’s path, steering it back into its lane.

These collaborations between the passive and active systems ensure not only the driver’s and passengers’ safety but also contribute to the safety of pedestrians and other road users.

The communication between these systems is also a big step towards autonomous driving. By autonomously responding to potential threats and maintaining vehicle control, these systems mimic the natural decision-making process of a human driver. Future improvements aim to enable these systems to anticipate and adapt to a wider range of situations, bringing us closer to Level 4 autonomous driving. However, it’s important to note that while these advancements enhance safety and convenience, they should never undermine the responsibility and attentiveness required when operating a vehicle.

Start Your Own ADAS Calibration Center with Car ADAS

Passive and active safety systems both play crucial roles, each with their own approach to accident prevention. Passive safety systems are designed to alert the driver to take action. On the other hand, active safety systems work proactively to prevent accidents from happening by taking control of the vehicle. Remember, as we embrace these technologies, it’s important to make sure they are properly calibrated and maintained. If you are interested in starting your own ADAS calibration center, contact us today!

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