Recently, the official appraisal results of the M7 serious traffic accident in Yuncheng, Shanxi Province have not yet been given, but the spearhead of online public opinion is directly pointed at the AEB failure, which has become the focus of heated discussions on the Internet because it is related to life safety.
AEB fault complaints are increasing year by year
AEB, that is, Autonomous Emergency Braking, is a preventive active safety technology, which is composed of three parts: driving environment information acquisition unit (sensor), electronic control unit (central processing unit) and execution unit (actuator). When the vehicle encounters a sudden emergency or is less than a safe distance from the vehicle in front and pedestrians in the non-adaptive cruise control state, the AEB system will actively brake to reduce the occurrence of collisions such as rear-end collisions.
In recent years, with the gradual popularization of intelligent assisted driving technology, AEB has become the standard configuration of more and more models, and major domestic car companies are also sparing no effort to develop and promote this function. According to the latest data from the China Passenger Car Association, the AEB function loading rate of passenger cars will reach 51.1% in 2023, an increase of 3.1 percentage points compared with 2022. However, in practice, AEB has become a double-edged sword, and if it fails, it can put the occupants in the car in a dangerous situation.
According to the data of Cheqq.com, from 2019 to April 2024, the number of complaints about AEB faults has accumulated nearly 600, covering many automobile brands, among which new power brands account for a relatively large proportion, such as Tesla, Xpeng, Leap, Ideal and Wenjie and other brands have been affected. Judging from the changes in complaint data, it shows a trend of increasing year by year, especially in 2023, the number of complaints will increase by leaps and bounds, with a year-on-year increase of nearly 2 times. From January to April this year, the number of complaints about AEB failures was 57, which was basically the same as the same period in 2023.
Specifically, the proportion of AEB failures in self-owned brand models is relatively high, exceeding 6% of the total. From the perspective of the time period of the problem, the proportion of complaints about failure within 1 month of car purchase is the highest, and the sum of the proportion of failure within 12 months of car purchase is close to 7% of the total, which shows that the probability of AEB failure is higher in the stage of quasi-new cars and new cars. In addition, it can be seen from the proportion of energy type complaints that AEB faults are more concentrated in gasoline models, and the proportion of pure electric and plug-in hybrid models is also relatively high, especially pure electric vehicles, accounting for more than 1/5 of the total number of complaints.
Success or failure is the original sin of AEB
Originally, the AEB function was created to help drivers reduce the incidence of traffic accidents, and was considered a line of defense for active safety. Unfortunately, this line of defense is not only ineffective in all situations, but has even become the cause of traffic accidents. Why does AEB strike frequently? Combined with the complaints of the vehicle quality network and the traffic accidents caused by AEB failures in recent years, there are no more than the following reasons.
1. The AEB function fails
When it comes to functional failures, there are two types of situations here. One is a complete failure, which means that the AEB function is not triggered. According to Mr. Li from Zhengzhou, Henan Province, he reported to the car quality network that he purchased an imported European brand SUV, and the vehicle had a rear-end collision with the car in front during normal driving, and the vehicle did not carry out emergency avoidance or active braking as officially advertised in the process, resulting in injuries and estimated economic losses of more than 200,000 yuan. The reason for the complete failure of AEB is mainly due to the failure of the hardware or software in the AEB system, such as the failure of the sensor to identify the obstacle in front of it, the software algorithm is buggy, etc., resulting in the AEB function cannot be triggered normally.
The other refers to the AEB function triggering "lag", in this case, the AEB function is not not triggered, but the triggering time node is delayed compared with the normal state, resulting in insufficient execution time of the braking system, and the vehicle cannot slow down or brake in time. The main reasons for this kind of problem are related to sensor performance, algorithm computing power, and braking system capabilities. This is actually very easy to understand, for example, the vehicle is equipped with a higher-definition camera and lidar, which can not only collect more details of obstacles, improve the accuracy of recognition, but also have a longer ranging ability to detect obstacles early. In addition, the optimization of algorithms and the improvement of computing power also play a crucial role in the accuracy and response speed of decision-making, and it is often possible to avoid a collision accident by shortening the decision-making time by a few milliseconds.
2. The AEB function is triggered by mistake
The so-called AEB function false trigger means that there is no risk of collision in front of the vehicle during driving, but the AEB function is triggered, which has a great impact on the comfort and safety of the vehicle. Especially for safety, there are many rear-end accidents caused by the sudden braking of the vehicle in front. Compared with AEB failure, the probability of false triggering is much higher. As can be seen from the complaint data of the vehicle quality network, about 47.4% of the complaints related to AEB false triggering accounted for the total. According to Mr. Zou from Shaoguan, Guangdong, he reported to Cheqq.com that the AEB active braking of a self-owned brand new energy SUV he purchased was mistakenly triggered 4 times in less than 1 month, which brought a huge shock to the occupants of the car, but fortunately did not cause a traffic accident.
Mr. Cai from Shanghai was not so lucky, he purchased a new energy vehicle of a foreign new power brand in the normal driving process of the provincial highway, the road condition is good for no reason, causing the rear car to have no time to avoid, resulting in a rear-end accident. There are many reasons why the AEB function can be triggered by mistake, such as sensor recognition errors, system algorithms, and special environments.
3. Driver's cognitive factors
In fact, in AEB-related traffic accidents, in addition to the problems of AEB itself, a certain proportion of the cause is related to the driver's cognition. In real life, some drivers rely too much on the AEB function advertised by car companies, believing that it can "stop the collision in time" before it happens, but the actual situation is the opposite. The first is some sudden traffic conditions, such as the common "ghost probe" in traffic accidents, and it is difficult for the AEB function to fully play its role at this stage.
There are also drivers who are ignorant of the AEB function and believe that the AEB can be triggered in the event of any collision hazard, but this is not the case. The AEB function has a working range, and it can only be triggered normally within the calibrated speed range, and the calibration of the trigger speed range is different for each car company. For example, in the recent accident of the M7 in Yuncheng, Shanxi Province, the vehicle collided at a speed of 115 km/h, while the Bosch solution used the AEB operating range was 4-85 km/h. At this stage, although the speed limit of some car companies is very high, it is often unattainable in practical applications. Previously, Ling Shiquan, CEO of Radar Automobile, said on his personal social media that "the maximum braking speed range of AEB collision avoidance in the industry is 50km/h-60km/h".
In addition, the driver's misunderstanding of the AEB function of his vehicle is also one of the factors that lead to traffic accidents. This part of the driver believes that since it is "automatic emergency braking", as long as this function is turned on, the vehicle can brake when encountering a collision danger. However, the actual situation is that the AEB function of different brands of models is not exactly the same, some models can complete the braking autonomously after the AEB function is triggered, and some require the driver to intervene to achieve braking. In the case of the Li L8 Max, for example, the automatic emergency braking releases the brakes after a maximum speed drop of 70 km/h. This means that if the automatic emergency braking is triggered at 80 km/h and the vehicle drops to 10 km/h, the vehicle will not brake and the driver must take over in time to continue braking the vehicle.
Of course, some car companies simplify the AEB function and avoid the importance in the publicity, which will also make some drivers "take it for granted" the AEB function, thinking that since the vehicle has the AEB function, it must be the whole car. It's like going to the store to buy shoes, and the one you buy is definitely one pair, and the store can't just sell you. However, it is precisely because of such misunderstandings that it can lead to some unnecessary traffic accidents. For example, in November last year, when the M5 intelligent driving version of the M5 intelligent driving version "rode" on the BYD dolphin was reversed, Yu Chengdong responded that "the rearward emergency braking of the vehicle does not recognize the stationary vehicle". However, the actual situation is that the M5 intelligent driving version does not set the AEB program for the rear of the vehicle. To put it bluntly, the AEB function of the vehicle only gives you half of it.
How to avoid problems caused by AEB
Image source: Li Auto's official website
Nowadays, AEB technology has been very mature in foreign countries and has been popularized on a large scale, but in China, it is only in recent years that it has gradually been paid attention to with the rise of intelligent networked vehicles, and it is currently in a stage of rapid development, and there are still some problems that need to be solved urgently.
Combined with the data of the vehicle quality network, complaints related to AEB failures are increasing year by year, especially the problems of complete failure and false triggering of AEB, which are related to the life safety of users and urgently need to be solved by car companies at the technical level. On the one hand, it is necessary to increase hardware investment and technology research and development. A single sensor is no longer suitable for the development of today's intelligent networked vehicles, and multi-sensor fusion can make AEB give full play to its active safety role. On the other hand, it is necessary to continuously optimize the system algorithm to improve the response time and decision-making speed. Of course, it is also very important to increase the test dimension and road test mileage of AEB after loading, and fully verify it for various extreme situations and road sections.
At the same time, car companies should provide positive guidance to consumers in the process of AEB publicity, fully fulfill their obligation to inform, and avoid excessive publicity and deliberate concealment. For example, when promoting the AEB function of vehicles, in order to attract attention, car companies often do not clearly inform consumers which models have this function and which do not. This may lead to the misunderstanding that consumers will have this feature as long as it is this model. But in fact, even if this feature is available in all models, it will vary depending on factors such as the type, brand, and number of sensors. In addition, there should be a clear explanation of the configuration of the AEB function, and which areas of the vehicle are not set up with the AEB program, which needs to be informed realistically to avoid misleading consumers.
Of course, in addition to car companies should always introspect and maintain a responsible attitude towards consumers, consumers themselves should also maintain a cautious attitude towards AEB, a function related to life safety, and have a correct understanding of its working principle and trigger conditions. In addition, it is necessary to fully understand the AEB function equipped with your own vehicle, especially for "whether human intervention is required for vehicle braking". In fact, in the ideal L8 Max case mentioned above, the car company has clearly explained the use of the AEB function in the user manual, but there should be very few consumers who can take the initiative to look through it. In the final analysis, AEB is only an active safety technology, which can only achieve "auxiliary safety", and the main body of safe driving at this stage is still the driver.
At present, the only AEB-related standard in the domestic passenger car field is GB/T 39901-2021 "Performance Requirements and Test Methods for Automatic Emergency Braking System (AEBS) for Passenger Cars", which means that the products produced by car companies can not be equipped with AEB systems, and there is a certain gap between the performance requirements of AEB and foreign standards. For example, the new regulations recently announced by the National Highway Traffic Safety Administration (NHTSA) require that the vehicle's AEB system must be automatically activated within 90 mi/h (about 144.8km/h) to prevent collisions with other vehicles. At present, most of the models equipped with AEB system in China have a starting speed of 80km/h, and the overall development lags behind foreign countries. Therefore, for the mandatory installation and performance requirements of AEB systems for passenger cars, it is hoped that relevant national departments will pay attention to them and formulate corresponding regulations and standards to promote the healthy development of AEB technology.
Summary:
According to data from a Euro-NCAP (European Association for the Evaluation of New Car Safety), vehicles equipped with AEB can reduce rear-end collisions by 38% and fatal crashes by 20-25%. As the basic function of intelligent driving technology, the importance of AEB is self-evident, although there are still problems of one kind or another, I believe that with the joint efforts of relevant national departments, car companies and consumers, AEB technology will continue to be upgraded and improved, play a more important role in the field of automotive safety in the future, and truly become a solid line of defense to protect the safety of drivers.