Levels of Driving Automation

SAE International has published a standard that provides a detailed definition of six levels of driving automation. These automation levels are widely used in the automotive industry to describe the capabilities of automated vehicles.

SAE Level 0 refers to a vehicle where a human has to do all of the driving, including steering, braking and accelerating. The vehicle can have some features that warn the driver or provide assistance in an emergency. For example, SAE Level 0 vehicles can have regular cruise control, automatic emergency braking or lane departure warning.

SAE Level 1 vehicles have a feature that assists the driver. It can be steering or brake/acceleration support. This means that the driver still needs to do the driving and constantly keep their attention on the task.

SAE Level 2 vehicles have several driver support features which can control speed and steering at the same time. But the driver still needs to supervise and monitor the driving environment. These features include lane centring and adaptive cruise control which adjusts the speed of the vehicle to keep a safe distance with the vehicles ahead.

SAE Level 3 is the first automation level where the vehicle has automated driving features and the driver can give the task of driving over to the vehicle. Level 3 vehicles can drive themselves but only under ideal conditions. They are able to detect the environment around them and make decisions based on that information. However, when the feature cannot execute a task or the system fails, a human driver has to take over.  With a Level 3 vehicle, the driver can turn their attention away from driving, but they must be ready to intervene when the vehicle asks them to.

SAE Level 4 vehicles can drive themselves without any human interaction. The driver can leave the driver’s seat or fall asleep. Automated driving is still only available in specific conditions, but the vehicle is able to park itself if the driver does not take over control. This Level describes driverless taxis in a specific area or public transport on a specific route.

SAE Level 5 is full automation. These vehicles need no human intervention and they can manoeuvre on all roads in any conditions. The vehicles have a more advanced environment detection system than Level 4 vehicles. This means that these vehicles can even drive off-road.

There are several SAE Level 2 vehicles on the market, but the step to SAE Level 3 has been difficult. In addition to technological advances, changes in the legislation are also needed for vehicles of Level 3+ to drive on our streets. Waymo has made the most progress with self-driving cars. They have been testing their SAE Level 4 vehicle in Phoenix, Arizona, USA and are now offering a driverless taxi system in that city.

  • Driving automation levels