Active safety systems are very advanced, but can they be used correctly?

As the popularity of passenger cars increases, car safety is receiving more and more attention. People are gradually aware of the role of seat belts, and wearing seat belts has gradually become our first habitual action after getting in the car. However, I have to tell you a truth: when the seat belt works, the thing we don’t want to happen has already happened. Whether the accident is serious or not, we can only passively leave it to fate. Therefore, we must also gradually change a concept: the so-called "my fate is in my own hands, not in the hands of God", instead of passively accepting it, it is better to take the initiative to hold safety in our own hands.

Studies have shown that if drivers can realize the risk of an accident 1 second in advance and take corresponding correct measures, most traffic accidents can be avoided. Active vehicle safety systems can predict dangers and provide prompts and warnings, which can greatly avoid accidents. Active vehicle safety systems mainly collect information through ultrasonic or infrared sensors and cameras installed on the outside of the car, and the computer makes intelligent judgments and responds. It is a large system with different modules, such as ACC adaptive cruise control, lane departure assistance and suppression, low-speed front collision prevention, etc. As the name suggests, these different modules are actually separated from each other and perform their respective duties. Today, we will dig deep into these high-tech vehicle safety systems and analyze their respective functions and characteristics.

1.ACC Adaptive Cruise Control System

After the ACC adaptive cruise control system is turned on, the car can automatically judge the road conditions ahead and realize automatic constant speed, acceleration, and deceleration. Under normal circumstances, we can set the following distance and speed range by pressing the buttons on the multi-function keyboard, as shown in the figure below. Of course, the functions of ACC of different brands are also different. For example, the ACC function of the Buick brand must be activated when the vehicle speed is greater than 25km/h, which is more traditional; the ACC function of Volkswagen is better combined with the pre-collision system; Honda, JEEP, and Ford's ACC have added a low-speed following function, which can cope with urban traffic jams well.

In this comparison, the traditional ACC represented by Buick has no advantage. The price increase is similar, but the function is not as good as Honda, JEEP, and Ford. After all, urban driving still accounts for a large proportion. Although Volkswagen seems to be unique, focusing on the judgment of road conditions and having higher sensitivity in braking and acceleration, if you think about it carefully, you will find that if I also make the pre-collision system well, I can naturally achieve this effect. Therefore, it can be predicted that those ACCs that can support "low-speed automatic following" will continue to attract consumers' attention for some time to come. After all, the price difference of such high-tech products is not large, and whoever has more powerful functions will be more powerful.

2. Lane departure assistance and mitigation system

Lane departure assistance and mitigation system means that when the driver unconsciously deviates from the original lane (usually determined by whether the steering wheel is turned), the system will issue a warning in a short time (within 0.5 seconds) and remind the driver or directly effectively suppress the deviation direction. The system is mainly divided into lane departure warning system (LDW) and lane keeping and departure mitigation system (LKA&RDM).

Lane Departure Warning (LDW) is equipped in German cars such as Volkswagen CC, BMW 5 Series, Mercedes-Benz E-Class, and American cars such as Buick. Most of them remind the driver that they have deviated from the lane by vibrating the seat or the steering wheel. For example, in Buick, if the car deviates to the right, the right part of the seat will be vibrated, and if the car deviates to the left, the left part of the seat will be vibrated, but there is no function to return to the correct direction. From the driver's point of view, vibrating the seat is better than vibrating the steering wheel. It is no exaggeration to say that whether the danger can be avoided may be within this 0.5 seconds. The vibrating seat can immediately remind the driver of the direction of deviation and return to the correct direction in time; while the vibrating steering wheel, you will feel that the entire steering wheel is vibrating, but you don't know whether there is danger on the left or the right side, which may increase the driver's nervousness and make improper operations or decisions.

Lane keeping and departure mitigation (LKA&RDM) systems are mainly found in Japanese cars, most notably Nissan and Honda, and American cars include Ford. It can not only effectively remind the driver that they have left the lane, but also automatically return the car to the correct direction. For example, Nissan and Honda's LKA&RDM can automatically guide the car back to the original lane; Ford's will have a very slight direction correction.

Whether it is automatic return to the correct direction or small correction, it is actually quite good. The automatic return function can directly avoid danger when the driver cannot control it in time, while the small correction gives the driver more control space. It is hard to say which is better or worse, each has its own advantages. But one thing is certain, LKA&RDM is definitely a new generation of lane departure assistance and suppression system that is better than LDW. This cannot be blamed on German cars equipped with LDW. Electronic technology is always updated very quickly, and everyone is very distressed~

It is also worth mentioning that both LDW and LKA&RDM collect road information through cameras. That is to say, once it is at night or in heavy fog, rain or snow, the system may become "short-sighted", and the driver needs to be vigilant at this time... Of course, Citroen uses infrared to collect road information, which is not included.

3. Low-speed forward collision avoidance system (FCW)

The low-speed front collision avoidance system is mainly composed of the vehicle front information recognition module, the intelligent judgment algorithm module, and the warning or active braking module. The low-speed front collision avoidance systems developed by different brands have different levels and focuses. One is the auxiliary system represented by the BMW 7 Series, which can brake but cannot completely stop. Another is the system that can completely stop, represented by the Volvo City Safety urban safety system and Buick CIB anti-collision automatic braking. It is hard to say which is better or worse. BMW focuses on assistance and pays more attention to the driver's control over the car, so the brakes are slower; Volvo advocates safety and intelligence, and the brakes are faster. The concepts are different.

In addition, the FCW systems of different brands have different abilities to identify road conditions and different focuses. For example, the Volvo City Safety system we have experienced can not only identify vehicles and people, but also static obstacles such as trash cans and guardrails. Buick CIB anti-collision automatic braking can not only identify vehicles and static obstacles, but also has an independent pedestrian recognition system, which is quite unique. Mercedes-Benz is a bit LOW, it will not react to non-moving objects, and it feels a bit outdated in comparison.

Since the development of FCW, the biggest technical difficulty is the recognition of road conditions: for example, the detection stability of motorcycles, tricycles, and large buses is insufficient; errors may occur in the judgment of children, pedestrians over 2 meters tall, speed bumps, etc. But it is not a one-size-fits-all approach. I am still optimistic about the major brands such as Volvo, Buick, and Audi. However, the FCW systems of some other brands have defects in recognition technology: insufficient recognition capabilities or incomplete application. Insufficient recognition capabilities not only require a big question mark in terms of reliability, but also easily disappoint consumers, such as Honda... There is incomplete application. Although it cannot be said to be useless, the technology is not mature enough and is definitely not perfect, such as Mercedes-Benz... Therefore, consumers who are interested in the low-speed forward collision avoidance system (FCW) can consider it, but don't have too high expectations. After all, this area requires a relatively high level of intelligence in the system, and no matter how good the system is, it is not as good as the human brain...

It is undeniable that active safety systems can cope with some unexpected situations, especially when using infrared, ultrasonic or microwave radar detectors, which are more reliable than the driver's naked eye in low-visibility weather, and can greatly improve driving safety. However, while we recognize the superiority of active vehicle safety systems, we must also understand that it is not autonomous driving, but at most semi-autonomous driving or assisted driving. Its main function is to avoid accidents to the greatest extent when the driver is distracted or makes mistakes in judgment. It can be said that it leaves a way out for safe driving. Therefore, we cannot rely too much on it. Safe and standardized driving is the right way.