Hands up! What you always wanted to know about automated driving

For years, manufacturers have been announcing that their cars will soon drive autonomously, without human intervention. A complex system of sensors, cameras, and artificial intelligence is supposed to take over the control. So far, the reality looks different – the technical hurdles seem high. But soon there will be movement in the robot car. From the beginning of 2025, Mercedes-Benz intends to offer autonomous driving up to 95 km/h in some of its vehicles according to Level 3.

By mid-2025, the Stuttgart automaker plans a so-called 2++ system for the city in China, and Nissan aims for automated driving by 2027. These are the most important questions and answers about autonomous driving and the different levels.

What is autonomous driving?

The automotive industry divides automated driving into five levels, calling them assisted (L1), partially automated (L2), highly automated (L3), fully automated (L4), and autonomous (L5). Only from Level 2 can a car independently steer, brake, and accelerate under certain conditions, such as with an adaptive cruise control or lane change assistant. However, the driver must keep their hands on the steering wheel and retains responsibility.

Only at Level 3 does the vehicle take over these tasks under defined conditions. The driver can engage in secondary activities like reading, watching videos, or working on their phone. However, they must take control of the car in critical situations and when the vehicle requests it.

At Level 4, the vehicle takes on driving responsibility, and the driver becomes a passenger. However, the driver can choose to take the wheel and drive if they wish. In autonomous vehicles at Level 5, the car handles all driving tasks by itself at all times – the vehicle no longer needs a steering wheel or pedals.

“Level 3 is a completely different world. At Level 3, the responsibility lies with the car. It must first inform the driver that they need to take over,” says Markus Lienkamp, Professor at the Chair of Automotive Engineering at the Technical University of Munich (TUM). This happens within four to eight seconds. “The vehicle must recognize that it can no longer continue driving on its own – and then maintain a safe condition for up to eight seconds. These are highly complex tasks,” says Professor Lienkamp.

What requirements do cars need to be able to drive autonomously?

For a car to drive highly automated according to Level 3, it must, among other things, independently handle certain driving tasks according to international regulations (UN R3157). So far, only Mercedes-Benz manages this on highways up to a current speed of 60 km/h. BMW will offer a similar system with the Personal Pilot L3 for the 7 Series starting in March 2025. No manufacturer has yet received approval for use outside highways, such as in urban areas.

Where are the problems with automated driving?

The challenge with automated driving is that the systems must always work 100 percent – 99 percent is not enough. The technical effort is immense: More than 40 assistants currently work with cameras, radar, and lidar in a Level 2 system like that of Mercedes-Benz.

Highly automated cars require monitoring systems such as cameras, lidar, radar, and ultrasound. In addition, high-precision maps and centimeter-accurate positioning via satellites support the robot vehicles.

“The step from Level 2 to Level 3 is enormous. For safety reasons, systems such as brakes, steering, and electronics in a Level 3 vehicle must be designed redundantly,” says Taner Kandemir, project manager for autonomous driving at Mercedes-Benz.

This ensures that if one component fails, the second can take over.

“If the automatic steering control fails at Level 2, the driver can take over. In Level 3, there is not enough time for this, so the car must access a safety system,” says Professor Lienkamp.

Where does automated driving work?

Automated driving so far works only on approved highway sections without construction sites, on the far-right lane, and only until nightfall – currently only in Germany and the US states of Nevada and California. There is currently no approval on country roads and in cities in Germany. From a technical point of view, a Level 2++ system is possible in Germany, but it lacks approval for use.

In China, a city system is currently in testing, but the vehicle still brakes somewhat abruptly. Next year, it should be available for order in China.

“In the future, we will also be traveling automated in urban areas,” says Taner Kandemir. “But the environment is very complex, so we are currently gathering further experience with development projects in China.”