Level 4 autonomous driving: sleeping at the wheel allowed

Contents

When Elon Musk makes an announcement, it is not a promise: "Definitely before 2027", the autonomous robotaxi called the Tesla Cybercab will be produced. The two-seater electric car has no pedals, no steering wheel and is expected to cost "under 30,000 US dollars". It takes two people and luggage wherever they want. In the brand's usual tam-tam and the accompanying sneering ("Elon-Time"), it could easily be lost that "previously Model Y and Model 3 Unsupervised FSD" are to be mastered. Musk also mentioned this. It would therefore affect the masses. What is new about the debate in the industry –, including at Mercedes or Volkswagen –, is that many passengers could already perceive driving as autonomous after Level 4 and not only with Level 5. Is that enough, and what does that mean?

Level 2: Assistants must be monitored

There is no international and uniform definition of the levels of automated driving, but there are conventions that are shared in Europe and the USA, where they are based on SAE J3016. Many new cars are equipped with at least Level 1 assistance systems. These include adaptive cruise control, which regulates the distance to the vehicle in front. The longitudinal guidance – deceleration and acceleration – is assisted in this case. If this longitudinal guidance is combined with lateral guidance – steering – and the car can handle driving tasks without human intervention, this is referred to as Level 2.

In both cases, the driver must always and continuously monitor the assistance systems. Errors must be corrected by the driver, who always remains solely responsible. Among other things, attention is demanded by touch-sensitive steering wheels that recognize when there is no hand on the wheel. In 2021, the Federal Highway Research Institute (BASt) has combined Level 1 and Level 2 under the term "assisted driving" to simplify matters and provide greater clarity.

BASt nomenclature: assisted, automated, autonomous

Level 3 in the BASt nomenclature is automated driving. The terms "partially automated" and "highly automated driving" are also commonly used for Level 2 and Level 3; from the BASt's point of view, however, the minor linguistic differences do not reflect the qualitative progress. From Level 3, drivers of cars or trucks may completely relinquish attention under certain and defined conditions (abbreviated ODD for "Operational Design Domain"). A manufacturer can interpret these conditions narrowly. For example, they can define that for Level 3 driving, the temperature must be above 5  degrees, the road must have at least two lanes in each direction, visibility must be clear and the speed must be below a certain level.

The person can turn away within this specified framework, but is obliged to be able to take over the driving task again within a transition period of ten seconds, for example. Important: In contrast to Level 2, in the Level 3 scenario the driver is not legally responsible until the moment the system prompts him to take over. Within the given framework, the manufacturer is liable, which explains, among other things, why they approach the subject so cautiously. On the other hand, the classification only defines the lower limit. It is therefore not forbidden to enable Level 3 off the highway under the exemplary conditions mentioned.

Some cars, such as the Mercedes EQS, are approved for Level 3 in the European Union. Both the speed (for the EQS now up to 95 instead of 60 km/h) and the weather (not at night or in the rain) are still considerably limited. Nevertheless, there is a gradual expansion. Under pressure from the US authorities, Tesla has added the addition Supervised to the so-called Full Self-Driving (FSD). This means that it is an assisted system according to Level [2]. Even the impressive recordings from the USA of long distances on which humans do not have to intervene do not change this.

Level 4 is the permission to sleep

The real advantage worldwide only comes when Level 3 is followed by Level 4. The BASt no longer speaks of highly automated driving as at Level 3, but of autonomous driving: The human driver can withdraw completely under the previously defined conditions (ODD) and does not have to be able to take over again. They can watch movies or sleep as soon as the system is active. The assistant can manage – at least – a precisely defined scenario completely on its own.

In Tesla-speak, this is Unsupervised FSD. If Elon Musk succeeds in realizing this definition before the Cybercab for Model Y and Model 3 for the years 2025 or 2026, it would be nothing less than the beginning of a cultural revolution. Whether this will succeed is disputed among experts. This is because there are not only differences in registration between Europe and the USA, but also within the USA. When asked by heise/Autos, Mercedes explained that the regulations are "very heterogeneous" internationally from Level 3 and that a worldwide "harmonization would be welcome". According to Mercedes, some US states allow self-certification(!) by the manufacturer without testing by additional institutions, while others prohibit this.

Level 4 is eligible for approval in Germany

In Germany, a law has been in force since June 2022 that generally permits the sale and operation of Level 4 systems. The Federal Motor Transport Authority (KBA) has approved a driverless parking system from Mercedes, which is still subject to extremely tight restrictions for the time being; it is more a matter of principle. Level 4, "highly automated" according to the current terminology and "autonomous" according to the BASt, will probably be perceived by most people as autonomous driving. As mentioned: sleeping at the wheel is permitted under certain circumstances.

Broad spectrum

The spectrum of Level 4 will nevertheless be very broad and perhaps disappointing at first: Because there are no traffic lights, no oncoming traffic and no pedestrians on the highway, autonomous driving will presumably start here. But similar to Level 3, the conditions for activation at the start could be very limited. When it starts to rain or at dusk, for example, the car could decide to head for the next rest area.

At the same time, experience with the current level 2 systems shows how wide the from-to range can be: A level 4 system is also considered as such if it moves the vehicle perfectly in summer and winter, on all roads and in all weathers, and the human can sit back. The demarcation to Level 5 means that all conceivable driving tasks, such as maneuvering on a campsite, can be mastered in all situations, even without humans. The actual leap is from Level 3 to 4, or in BASt's nomenclature the transition from automated to autonomous driving.

"Vision only" vs. radar and ultrasound

The two different technical approaches to solving the problem are worth mentioning in this context: Tesla relies exclusively on cameras and calls this "Vision Only". Tesla's argument is that humans also orient themselves purely optically. Good headlights, several cameras and powerful computers in the vehicle and in the backend should lead to the goal. Tesla argues that even digital and centimeter-accurate maps no longer make sense in this way: The car orients itself like a human.

The rest of the industry assumes that radar and ultrasonic sensors offer a clear additional benefit over cameras in poor visibility, are indispensable and increase safety. At Mercedes, four core areas are also designed with redundancy, namely the brakes, steering, power supply and parts of the sensor system. This dual design in these areas is not explicitly required for approval. What is required, however, is the ability to make an emergency stop under all circumstances, from which most manufacturers interpret an implicit redundancy obligation.

In Europe, the level 3 systems from BMW and Mercedes currently lead the field for the time being. However, it can be assumed that Tesla has long been collecting millions of kilometers with FSD in test vehicles. Not only in Texas or California, but also in Norway, Germany and Spain.

(dmk)