Mercedes Benz pre safe system
What does Mercedes PRE SAFE do?
The main function of PRE SAFE® is to prepare your vehicle for a collision or rollover before it takes place. How does the system sense a possible accident? Thanks to its numerous sensors and embedded artificial intelligence, it can anticipate potential emergency situations. When it detects an imminent threat, such as a frontal or side collision, the Mercedes PRE SAFE system takes preventive measures to protect the occupants of the vehicle
What is the PRESAFE brake in Mercedes-Benz?
Mercedes PRE SAFE brake with pedestrian recognition
The pedestrian detection complements the function of the Mercedes PRE-SAFE Brake by detecting individuals in the vehicle’s path. The Mercedes PRE-SAFE Brake is only active in the speed range of v = 7 to 200 km/h. In the case of fixed obstacles, the Mercedes PRE-SAFE Brake is only activated up to a maximum speed of v = 72 km/h and reacts to obstacles such as stationary vehicles or pedestrians in the vehicle’s path.
When the Mercedes PRE SAFE Brake detects a risk of collision with obstacles in the detection zone of the radar sensors or the stereo multifunction camera, the instrument cluster emits an optical or optical-acoustic warning. If there is no reaction from the driver (evasive maneuvers, braking in case of danger assisted by BAS PLUS), partial autonomous braking is initiated.
If there is still no reaction from the driver, provided all conditions are met, the vehicle is braked to a stop by full braking. This can prevent accidents up to a speed of 50 km/h under the most favorable conditions.
Mercedes PRE SAFE Rear
The Mercedes PRE-SAFE Rear function extends preventive passenger protection to situations of danger from traffic approaching from behind. The radar sensor located in the center of the rear bumper detects traffic behind the vehicle.
The radar sensor calculator analyzes the approach speed and distance of vehicles approaching from behind based on information from the radar sensor placed in the middle. Based on this data, various measures to mitigate the potential consequences of an accident for passengers are initiated.
The possible measures are represented chronologically on the following graph and are explained on the next page.
1. Vehicle approaching from behind
2. Vehicle equipped with Mercedes PRE-SAFE Rear
3. Detection zone of radar sensor in middle of rear bumper
t1. Detection of the vehicle and warning about approaching traffic from behind
t2. Vehicle preparation for collision avoidance
t3. Activation of passenger protection measures (vehicle depicted in fully braked state)
t4. Vehicle immobilization after collision
Detection of the vehicle and warning about approaching traffic from behind (escalation level t₁)
If a vehicle approaching from behind is detected by the radar sensor in the middle of the rear bumper and the radar sensor calculator evaluates it as posing a collision risk, the driver of that vehicle is alerted by the activation of the rear hazard lights.
Functional process of preparing the vehicle for a collision (escalation level t₂)
Impact at approximately t = 300 ms:
If the radar sensor calculator does not register any deceleration of the vehicle approaching from behind via the approach speed or registers insufficient deceleration, the vehicle is preemptively “braked to a stop” by increasing the braking pressure.
Full braking significantly reduces both the load on the occupants (whiplash) and serves to protect other road users. Uncontrolled movements of the vehicle after a rear collision, which can lead to chain collisions (collision with the preceding vehicle, collisions with pedestrians or other road users in crossing situations), are reduced.
Functional process of activating vehicle occupant protection measures (escalation level t₃)
Impact at approximately t = 100 – 50 ms: If the radar sensor calculator detects an imminent rear impact based on the approach speed of the following vehicle, preventive measures are initiated for occupant protection.
The driver or passenger is secured in the seats by activating the reversible belt tensioners, to optimize the protective effect of conventional restraint systems.
Functional process of vehicle immobilization after the collision (escalation level t₄)
After approximately t = 2000 ms after the impact: Following a rear collision, the braking pressure is maintained for approximately t = 2000 ms.
What is PRESAFE inoperative Mercedes?
When you see the “Pre Safe Inoperative” message on your Mercedes dashboard, it means that the PRE SAFE system is unable to assist you in the event of an unavoidable accident. In other words, you’re left to handle the situation on your own.
More Information, check the following article
In summary,
The PRE SAFE system in the Mercedes Classe C W205 is a remarkable example of Mercedes-Benz’s ongoing commitment to automotive safety. With its preventive capabilities and intelligent features, Mercedes PRE SAFE helps protect passengers in the event of a potential accident. It’s a technology that provides peace of mind and confidence during every journey aboard the Classe C W205.
