The 6 Levels of Autonomous Driving


There was a time not too long ago when autonomous driving was something only found in science fiction novels or shows. The time has arrived, where over the next decade, the car industry is set to undergo the biggest changes it has seen in 30 years. 

As we stand at the entrance to a new era of automated driving, let’s get a closer look at the five levels of autonomy, and its interconnection between the driver, the car, and the world.

Photo by metamorworks/Adobe Stock Images

Photo by metamorworks/Adobe Stock Images

The 6 Levels of Autonomous Driving

The Society of Automotive Engineers, SAE International, published the classification system titled “Taxonomy and Definitions for Terms Related to Driving Automation Systems for On-Road Motor Vehicles". Each level is categorised by the extent a driver is required to intervene, and how attentive they need to be behind the wheel of an autonomous vehicle. 

There are six levels of automation in the SAE’s classification, ranging from level 0 to level 5.

Level 0: No Automation

The most commonly owned type of vehicle, level 0 vehicles have no autonomous controls at all. The human driver at the wheel is solely responsible for all aspects of driving, including braking, parking, and reacting to traffic hazards. Regular cruise control is included in this category too, as the ability to maintain a speed set by the driver is not autonomous.

Level 1: Driver Assistance

Driver assistance systems support the driver but do not take control. The vehicle is equipped with some features that allow the car and driver to share isolated control, but the driver is still responsible for monitoring the road and operating the vehicle. Under select conditions, the car can control either the steering or vehicle speed, but not both simultaneously. Examples of level 1 autonomy include adaptive cruise control which independently adjusts the distance of the vehicle to the car in front of you, lane-keeping assistance, and parking assistance.

Level 2: Partial Automation 

This is where the true autonomous experience of driving begins, allowing the driver to disengage from physically operating both the steering wheel and foot controls at the same time. Level 2 cars have internal systems that will control all aspects of driving: steering, acceleration and braking. However, tactical manoeuvres like traffic signal response, switching lanes, or hazard response will still fall on the driver. Thus, although partial automation is sometimes dubbed “hands-off driving”, the driver is still required to keep their hands on the wheel at all times.

Level 3: Conditional Automation

In ideal conditions, the car is able to manage most aspects of driving, including situational awareness. The system will prompt the driver to intervene if conditions extend beyond the scope of level 3 autonomy, such as speeds exceeding 60km/h, if the car ventures past geofenced areas, experiences bad weather, or approaches road works. The driver is allowed to disengage and sit back but has to be ready to intervene when alerted. This level of autonomy is a little debatable because the instantaneous transfer of control from car to driver may pose some difficulties if the driver has not been paying attention to the road for a while. The first vehicle to boast level 3 autonomy is the Audi A8 in 2019.

Level 4: High Automation

Fully autonomous, a level 4 car will be able to perform all dynamic driving tasks and monitor road conditions without any human input or oversight, but only limited to the operational design domain of the vehicle, defined by predetermined factors such as road type or geographic area. In other words, level 4 cars are so capable that the driver will be able to sleep in it if they want, but will need to intervene under unusual environments like poor weather conditions. If there is no human intervention, the car will automatically and safely navigate itself to a parking space. An example of a level 4 vehicle is Google’s Waymo.

Level 5: Full Automation

The holy grail of autonomous driving. At this level, the vehicle assumes 100% of all driving functions and expects its performance to rival that of a human driver, while including safety features and emergency protocols. The car would be able to drive itself anywhere, no longer bound by geofenced restrictions, and in any condition with no human interaction necessary, save for entering a destination. These vehicles have no more need for steering wheels or user-controlled outfitting, and the person operating it would not require a driving license. There are no commercial productions of level 5 vehicles as yet, but companies like Zoox, Google’s Waymo, and other top players in the industry are working towards the goal.

Although we still have a considerable way to go before level 5 vehicles become mainstream, the rate of progress in the field of autonomous driving has been meteoric. It won’t be long before true self-driven cars become commonplace!