Levels of Autonomous Driving

Nowadays, some electric vehicles come with advanced driver assistance systems (ADAS) which automates some functions of driving on a sustained basis. To understand the differences between electric vehicles (EVs), autonomous vehicles (AVs) and robotaxis, we need to know the 6 levels of autonomous driving.

The level to which a vehicle can be described as autonomous is set by the SAE International (Society of Automotive Engineers).

If a vehicle has Level 0, Level 1, or Level 2 driver support systems, an active and engaged driver is required. He/ she is always responsible for the vehicle's operation, must supervise the technology at all times, and must take complete control of the vehicle when necessary.

In the future, if a vehicle has Level 3, Level 4, or Level 5 automated driving systems, the technology takes complete control of the driving without human supervision. However, with Level 3, if the vehicle alerts the driver and requests he/ she takes control of the vehicle, he/ she must be prepared and able to do so.

Level 0 refers to a vehicle that has no driving automation technology. In this case, the driver is entirely in charge of operating the vehicle's movement.

However, at Level 0, driver support systems that may temporarily intervene during driving may be present. Examples include stability control, forward-collision warning, automatic emergency braking, blind-spot warning, and lane-keeping assistance. These technologies are considered Level 0 because they do not drive the vehicle but offer alerts or momentary action in specific situations. The majority of vehicles on the roads are Level 0.

At Level 1, the lowest rung of automation, a vehicle has at least one driver support system that provides steering assistance OR braking and acceleration assistance. The driver remains responsible for driving the vehicle and must be prepared to take control at any time and for any reason.

Adaptive cruise control is an example of a Level 1 driver assistance technology. It maintains a safe following distance between your vehicle and traffic ahead without any intervention by the driver. A steering assistance feature, such as lane-centreing assistance or lane-following assistance, would also qualify as Level 1 autonomy.

However, a vehicle with both of these features working together qualifies as Level 2 driving automation.

Level 2 applies to a large share of the EVs that are on the market today. Level 2 driving automation applies to vehicles with ADAS that can take over steering, acceleration, and braking in specific scenarios. But, even though Level 2 driver support can control these primary driving tasks, the driver must remain alert and is required to actively supervise the technology at all times.

For the record, and according to what the automaker told the state of California, Tesla's new Full Self Driving technology is a Level 2 system, and it will remain so when Autosteer for city streets arrives.

The leap from Level 2 to Level 3 automation is significant. There no Level 3 American EVs on American roads yet.

Level 3 is known as conditional driving automation. It uses various driver assistance systems and artificial intelligence to make decisions based on changing driving situations around the vehicle. People inside the vehicle do not need to supervise the technology (i.e. they don't need to keep their eyes on the road all the time), which means they can engage in other activities. However, a human driver must be present, alert, and able to take control of the vehicle at any time, especially in the case of an emergency due to system failure.

No, you still cannot take a nap while sitting in the driver's seat of a Level 3 conditionally autonomous vehicle.

Since L3 is the first level to allow drivers to take their eyes off the road, official certifications and approvals are needed before OEMs can claim a vehicle to be L3. These certifications are often issued by regional transport authorities and highway safety agencies.

In May 2022, Mercedes-Benz became the world's first manufacturer to get approved by German transport authorities to legally operate its L3 Drive Pilot on the country's public roads, sold as an option on Mercedes-Benz S Class and Mercedes EQS. This means that those with L3 Drive Pilot are legally allowed to eat, draft emails, or watch videos on the Autobahn. Still, given that L3 autonomy is conditional, if the vehicle loses the environmental or locational conditions to operate at L3, it will prompt the driver to take control within ten seconds. If the driver fails to respond in ten seconds, the car will automatically turn on emergency lights and decelerate to a full stop on the side of the road, then unlock the doors in case first responders might need access to the cabin.

Mercedes-Benz further announced that it has become the first manufacturer to receive L3 certification in the United States, from the states of Nevada and California. However, since L3 approval is granted at a state level in the US, the system is only considered L3 in Nevada and California for now. Nonetheless, the OEM says its Drive Pilot is fully ready to deliver L3 autonomous driving in all 50 states.

This is the highest level of vehicles which are currently available.

Level 4 autonomy does not require any human interaction in the vehicle's operation because it is programmed to stop itself in the event of system failure. Since a human driver is never needed, a Level 4 vehicle may not have a steering wheel and pedals.

And yes, at Level 4, you can take a nap while riding in the vehicle.

Level 4 driving automation technology is for use in driverless taxis (robotaxis) and public transportation services. Such vehicles will be programmed to travel between Point A and Point B and restricted to specific geographic boundaries by geofencing technology. Certain conditions may limit or cancel Level 4 autonomous vehicle operation, such as severe weather.

There are already some robotaxis on the roads. They include Google's Waymo, GM's Cruise, Baidu's Apollo Go, Pony.ai and Volkswagen's ID Buzz.

Waymo and Cruise already offer driverless taxi rides to the general public, with Waymo starting in Dec 2020 in a part of Phoenix, Arizona. Having provided a total of more than 2 m rides and covered a few hundred million kilometres by Q1 2023, Apollo Go is the world's largest autonomous ride-hailing service provider.

As the highest classification of driving automation, Level 5 means a vehicle can drive itself everywhere in all conditions without any human interaction and not even emergency manual intervention. A Level 5 vehicle is neither bound by geofencing nor affected by weather and transports human beings comfortably and efficiently without requiring a driver. The only human involvement will be to set a destination.

No vehicles are currently available at this level.

I want to point out differences in the levels. The difference between levels 2 and 3 is that you must keep your eyes on the road at all times in level 2. In level 3, you are legally allowed to take your eyes off the road to eat, draft emails, or watch videos. But the driver must take control when prompted by the system. It involves higher technology than level 2 and the difference is not simply legal.

Levels 4 and 5 are for fully AVs. The differences are that in level 4, the driving is limited to certain cities on a small scale, certain time limits and certain conditions. In level 5, there are no restrictions. A driver is not necessary for both levels.