Learning to Run at Level 3

Author: Joachim Geiger

Aug 17, 2022 Digitalization / Safety on the road

Many drivers have long been imagining what driving at SAE Level 3 would be like. Yet Mercedes-Benz is so far the only car manufacturer to offer the first highly automated vehicles. But why is the industry having such a hard time with this level? We asked DEKRA expert Walter Niewöhner where the journey is headed.

In December 2021, the German Federal Motor Transport Authority (KBA) granted car manufacturer Mercedes-Benz approval for a vehicle system that enables highly automated driving for the driver. With this system, which meets the technical requirements of UN Regulation No. 157, the Swabians are the first manufacturer in the world to have an approved system at SAE Level 3. Is Level 4 already within reach?
Walter Niewöhner: Basically, a Level 4 car drives entirely by itself in every conceivable traffic situation. We still have a very long way to go for this scenario. Level 3 means that a system permanently takes over longitudinal and lateral guidance. In doing so, it must also recognize its functional limits: If the necessary conditions are no longer met, it must prompt the driver to take over the task of driving again. However, the Drive Pilot that Mercedes-Benz is now offering is not a Level 3 system for every driving situation. Among other things, the framework requirements state: driving only on highways or highway-like roads, driving in one lane, and up to a maximum of 60 km/h, in daylight, and temperatures above 4°C.
When does anyone drive only 60 km/h on highways? Really only in traffic jams or roadworks. Which would make the new system nothing more than a traffic jam pilot?
Niewöhner: The system is functionally related to a specific aspect of vehicle use, namely driving in slow-moving traffic or in a traffic jam. If you’re driving in such a situation, you activate the system. The vehicle will then continue in its lane until the driver takes over again. In this situation, the system relieves the driver – he could read the newspaper in the meantime, for example. He is only obligated to be able to take back control of the vehicle within ten seconds.
Well-equipped cars have assistance systems that can relieve the driver of tasks such as maintaining lane or distance. So what exactly is the progress?
Niewöhner: It would be a fallacy to assume that a vehicle with Level 2 has exactly the same capabilities that the higher Level 3 necessarily requires. The Level 2 system can indeed keep a vehicle in its lane. But it does only that – keeping the vehicle in its lane and checking whether there is a preceding road user. This system is called “Advanced Driver Assistant System” (ADAS) – the Level 3 system, on the other hand, is called “Automated Driving System” (ADS). There might only be an “A” missing, yet the meaning is completely different. From Level 3 on, a system has to be able to do much more. The big and significant step is that technology takes over responsibility in performing the driving task. At this point, the driver is truly and completely out of the picture – he is eliminated as the person responsible.
As an example, the Drive Pilot may only be activated during the day, on a dry or slightly wet road. It needs recognizable lane markings and a preceding vehicle. With so many tangible restrictions, what benefit does the system bring?
Niewöhner: I would not call them restrictions in this case. We’re talking about the so-called “Operational Design Domain” (ODD). The manufacturer uses it to define an operational area, within which the system works. We should by no means malign the system because of this. Many people have far too high expectations when they’re told that we can now drive automatically. The Drive Pilot practically represents the infancy of automated driving. These are the first steps; later, with increasing experience, other capabilities will be added. The technology must be given the time it needs. These experiences cannot be implanted in the technical systems overnight.
The World Forum for Harmonization of Vehicle Regulations (WP 29), which is responsible for the harmonization and further development of technical regulations in vehicle construction under the umbrella of the United Nations Economic Commission for Europe (UNECE), is now taking the next step in Level 3. On June 22, it gave the green light for a new version of UN Regulation No. 157, which will take effect in January 2023. What does this mean for the automotive industry?
Niewöhner: In a sense, the new version breaks open the old regulation. In future, the highway speed will be increased from the current 60 to 130 kilometers per hour. It will then also be possible to change lanes independently. This will undoubtedly be a milestone in the development of highly automated driving at Level 3. For car manufacturers and their customers, this will make things really interesting. Just think of switching lanes: This means that a vehicle must now also keep a very close eye on the neighboring lane to which it means to change. What is happening in front, what is coming from behind? All this has to be put in relation to each other. The various working groups under WP 29 have put a lot of effort into this with the corresponding set of rules.
Speaking of working groups. You are not only an expert in driver assistance systems, but also a representative for international committees. Is DEKRA actually part of defining the rules for automated driving at UN level?
Niewöhner: Only in an indirect way. DEKRA is a member of the Comité International de l’Inspection Technique Automobile (CITA), an international association of vehicle inspection organizations. As a representative of CITA, I’m involved in several WP 29 working groups – including the Special Interest Group on Regulation 157, which deals exclusively with what the upgrade to 130 km/h with lane change must look like, and which will later also be applied to other vehicle classes.
Give us a glance behind the scenes. How is the work being done?
Niewöhner: The approach to automated driving is quite particular. With conventional technology, it’s often the case that a product first comes onto the market. Only then do the committees clarify what should actually be regulated and prescribed with regard to the newly introduced technology. With highly automated driving, it’s quite different. Here, rules are drawn up for technologies that do not yet have any practical experience.
So what would a highly developed ADS have to provide?
Niewöhner: It must communicate safely with the driver, comply with traffic rules, and master difficult traffic situations. That sounds simple at first. But these are huge challenges for software developers. They basically have to translate the texts of the various countries’ road traffic regulations into rules for a digital system. But how do you explain to a system that it should give way to a pedestrian at a crosswalk? There is currently no absolutely reliable way to predict a pedestrian’s behavior based on speed of movement and walking direction. The pedestrian is the only road user who can stop within one second and continue moving in any other direction in the next second. This makes it very difficult for developers.
And what does that mean specifically for the rewrite of UN Regulation No. 157?
Niewöhner: First of all, the new set of regulations for Automated Driving Systems only applies to passenger cars and light commercial vehicles. These systems may only be activated on roads where pedestrians and cyclists are not permitted. The roads themselves must be separated from oncoming traffic with a physical barrier. The driver must be able to override the system. The system, in turn, must be able to prompt the driver to take back control of the vehicle at any time. In fact, the regulations are incredibly complex and define very high safety requirements. Automakers must, for example, install a black box in their vehicles that documents every activation of the automated driving system and every automatic lane change. In addition to the technical requirements, measures for testing and type testing as well as monitoring and evaluation also play a role. New functions must also meet the cybersecurity and software update requirements defined in the relevant UN regulations.
Coming back to the imagery of infancy and first steps, how do you think the old and new rules of UN Regulation No. 157 relate to each other?
Niewöhner: With the old version the child is learning to walk, with the new one it can already run.