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In Five Steps to a Self-Driving car

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Since the 1950s, not just automotive engineers have been fascinated by the dream of fully autonomous driving. What stage are we at today? When will it become a reality?
Christoph Reifenrath, September 06, 2017
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Christoph Reifenrath has been a TV and print journalist for 35 years and is part of the ZF Copy Team. His favorite part of the job is delving into complex technical topics.
The car shows up as ordered as if by magic and chauffeurs its passengers safely through the city and over country lanes and highways. The occupants can talk among themselves, watch movies and even sleep on long trips – the automotive mobility of tomorrow no longer needs a human driver. What the development stages look like for such a fully-automatic robo-taxi were defined by SAE International in 2014 in the J3016 standard. At the same time, the standardization organization made it clear that the stages described are more descriptive than normative and legally binding, and that there may be vehicles with features of different levels.

A glimpse in the future

Approximately in 2025, level-4-vehicles are likely to hit the market, according to experts. The driver is allowed to turn his attention completely to other things and, as long as the systems are working, no longer has to keep an eye on what is happening in traffic.

Level 0: No Automation

Level 0: No Automation

In principle, the automotive pioneers already drove in this manner. The driver steers, accelerates and applies the brakes himself. For purists this is still the epitome of automotive freedom. But because people make mistakes, this form of mobility is causing problems in society as the number of vehicles constantly increases. Solving these problems is one of the goals of autonomous driving.
Driver: Has complete control.

When: The past.

The “non-automated” car has already had its day. With level 0, there are no assistance systems at all; the driver is in complete control of the car.
Level 0: No Automation

Level 1 – Driver Assistance

Level 1 – Driver Assistance

The driver is fully responsible for control, both physically and legally. He therefore must always pay attention to traffic, have both hands on the steering wheel and be ready to brake. However, he is supported by assistants which, like an attentive front-seat passenger, also monitor parts of the vehicle environment. By means of acoustic, optical or tactile signals, they can indicate errors or inattentiveness or help to prevent them from happening using driver-selected settings that can always be overridden. These systems can be switched off, and they usually operate only in certain speed ranges. In case of bad weather (soiled sensors), they can also only function to a limited extent or not at all. One example of this is cruise control, which controls the vehicle’s speed and, in a more advanced configuration, the distance to the car ahead. Correctly used, the system prevents speed limits from being exceeded and tailgating of the car ahead. The assistant that indicates vehicles in the blind spot when changing lanes works according to the same principle. It provides a warning, but the driver independently decides what to do.
Driver: Always responsible for longitudinal and transverse control; supported in specific cases.

When: The present.

Meanwhile, drivers of nearly all vehicle classes benefit from Advanced Driver Assistance Systems (ADAS) such as adaptive cruise control, lane departure assistance, park assist or emergency braking assistance.
Level 1: Driver Assistance

Level 2 – Partial Automation

Level 2 – Partial Automation

The most important difference from driver assistance systems of level 1: The system has full access to gas, brakes and steering. The current top models of premium manufacturers also monitor large parts of the vehicle environment using sensors. In this way these vehicles can automatically follow the lane or car ahead and recognize changing speed limits as well as adjust the vehicle’s speed accordingly in certain situations, such as on highways. On divided roads, they can also overtake other vehicles and take evasive maneuvers. In traffic jams, they automatically apply the brakes and can drive off again within a defined period of time. Despite these extensive features, the driver alone is responsible for monitoring the environment, according to the SAE definition. To ensure the constant attention of the driver, level 2 vehicles require the steering wheel to be touched on a regular basis. Up until a few months ago, only cars up to level 2 were permitted in Germany. On May 12, 2017, the Federal Council approved a law that allows highly automated driving of the next level. Germany is thus one of the first countries ever to create a legal framework for volume production use of such vehicles.
Driver: Has to monitor the system at all times.

When: Since 2016

The first semi-automated luxury-class vehicles hit the streets in 2016. These vehicles handle complete lateral and longitudinal control independently in predictable surroundings such as highways, even at high speeds. However, the driver must be able to monitor the system at all times and intervene immediately. That means that reading the newspaper remains taboo.
Level 2 – Partial Automation

Level 3 – Conditional Automation

Level 3 – Conditional Automation

From this level upwards, the vehicle also takes over complete monitoring of the environment – provided that the respective legal framework is in place. SAE states that the human driver may attend to other activities. However, he still acts as the fail-safe system. When the systems reach their limits, the driver must be able to intervene at any time after a warning period. In terms of technology, the industry has reached this level. but there are still challenges: For example, how is the human on board to keep their attention up during a possible situation of many hours of highly automated highway driving? On the other hand, how can the vehicle schedule individually required handover periods without precise knowledge of the condition of the driver? The question also arises as to how unambiguously distributed responsibilities can be achieved at all times. ZF has already presented approaches to solving these problems in its Vision Zero Vehicle. First level-3-vehicles will hit the market approximately in 2020.
Driver: May pursue non-driving activities.

When: Starting around 2020.

From level 3 onwards, the driver no longer has to keep an eye on the environment as long as he is able to take over the steering wheel again after being prompted with sufficient time to take control.
Level 3 – Conditional Automation

Level 4 – High Automation

Level 4 – High Automation

This dilemma is not resolved until level 4: The driver – frequently then more likely to be a passenger – is allowed to turn his attention completely to other things and, as long as the systems are working, no longer has to keep an eye on what is happening in traffic and no longer needs to be ready for sudden intervention. The car itself now forms the fail-safe system: Even in exceptional situations such as partial or complete system failures, it always has to provide his own exit strategy, including bringing the vehicle to a safe stop. As long as the system is in operation, responsibility is clearly with the vehicle manufacturer for the first time. Numerous companies are already on the road with test vehicles of level 4, and it is expected that such vehicles are scheduled to come onto the roads in production volumes in 2025. ZF will also contribute to this development step with sophisticated safety and assistance solutions.
However, in order to be able to implement fully automated driving in environments with many other traffic users, there are still several hurdles to be overcome in accordance with the present state of technology:
  • Car2X and Car2Car communication
Cars must be able to communicate with their environment, with other vehicles and with other road users such as cyclists, pedestrians or trams. Only then can the cross-traffic pre-warning periods be reduced to the required degree in case of complicated intersection situations where detection by sensors is too slow. It is also very difficult for sensors to detect traffic light colors under certain circumstances, making it necessary for them to announce their phases. A uniform standard and the necessary communication infrastructure must be created for all of this.
  • HD maps / positioning
Just coming into contact with the curb can bring an abrupt end to a relaxing drive. Automated cars therefore need to know where they are driving more precisely than the current GPS resolution and available maps allow. Providers such as Baidu Maps, Google, Here and TomTom are already working hard on high-resolution maps accurate to the centimeter which also contain all kinds of details about the infrastructure. The task is immense, because to allow automated cars to travel around the world, every public road has to be measured and the material must always be up-to-date. But even the most accurate map is useless if the vehicle does not know exactly where it is. Particularly in cities but also in tunnels and other problem areas, a reliable reference system that makes the GPS information even more precise will be essential.
Driver: No longer has to monitor the system.

When: Starting ca. 2025.

From the early 2020s onwards, fully-automated driving is now forecast to become a reality. No one will have to monitor the system anymore, since it can do that itself, ensuring “minimum risk conditions,” be it on the highway, on back roads or in town.
Level 4 – High Automation

Level 5 – Full Automation

Level 5 – Full Automation

Only when all these challenges are met can cars be fully autonomous under most weather conditions. Consequently, they will need neither a steering wheel nor a gas or brake pedal. Level 5 would thus be achieved according to SAE. Google has been experimenting with such vehicles on public roads since 2015, but there were still significant restrictions in terms of speed, routes and ability to operate in bad weather. The company has now discontinued development of its own vehicle. Traditional car manufacturers, along with new players, are continuing to pursue the goal unabated. How long it will presumably take until such cars are permitted and driving on the road is difficult to predict, due to various challenges.
Open questions and numerous opportunities
Many problems need to be dealt with before people will just be passengers in completely autonomous vehicles on all roads. For example:
  • Insurance and ethical issues need to be clarified
  • The autonomy functions must be “one hundred percent” safe and reliable under most environmental conditions
  • There must be improvements in sensor technology and image evaluation
  • It is necessary to develop high-performance hardware and software that can ensure processing of enormous data volumes at higher driving speeds or in unclear traffic situations with many different traffic users in the necessary time
  • The legal framework must be adapted accordingly worldwide
  • The necessary 5G network must be comprehensively available
One thing is already certain today: Fully autonomous vehicles will result in considerable changes in society as soon as they become reality. However, they also offer great opportunities: Children, adolescents, the elderly and disabled people would have unrestricted access to individual mobility for the first time. Our cities would have more quality of life, and the number of traffic accidents could drop drastically, along with traffic-related emissions. Achieving these goals together with its partners is the declared objective of ZF as part of “Vision Zero.”
Driver: Not required.

When: ?

Autonomous driving ultimately transforms the vehicle into a chauffeur. At this stage of the revolution at the latest, both interior and exterior automobile design will change radically, since drivers will be entirely free of having to drive and pay attention.
Level 5 – Full Automation

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