Is Your Car Autonomous? The 6 Levels of Self-Driving Explained

Autonomous cars are sharing the road with drivers in select cities, but what counts as self-driving? In the US, the National Highway Traffic Safety Administration (NHTSA) has recognized standards developed by SAE International since 2016(Opens in a new window), which outline six levels(Opens in a new window) of driving automation. These levels identify how autonomous a vehicle can be; does the car need a human behind the wheel or can it navigate the streets solo, for example? Here’s what each level means.


How Do We Define ‘Self-Driving’?

drive pilot sensors


Mercedes’ Drive Pilot system uses cameras and sensors to gather info on its environment.
(Image: Mercedes-Benz)

The average person may not know there are levels of self-driving technology; most of us picture vehicles as either self-driving or not. But there’s some nuance to vehicle automation tech, with multiple steps between a car with no automated driving features and one that pilots itself.

Autonomous driving systems perceive the environment around a car via a series of sensors, then take preprogrammed actions based on what those sensors detect. Ultrasonic, radar, Light Detection and Ranging (LiDAR(Opens in a new window)), and other sensors are positioned on the car’s body to make as thorough a picture of the surrounding environment as possible. That information lets autonomous vehicles do things like parallel park or detect water on the road and adjust accordingly.

A vehicle’s level of automation depends on how much of what the SEA calls the dynamic driving task (DDT) is done by a person and how much is done by AI. The less human intervention an automated car requires to operate, the higher its level of automation.


Level 0 – No Automation

Most vehicles on the road right now are Level 0; conventional cars with no automation features whatsoever. A human is entirely responsible for piloting it safely to and from its destination, and the car has no parking assistance or other automated safety features like lane assist. 


Level 1 – Driver Assistance

toyota rav4


Toyota’s Rav4 features an adaptive cruise control system called Toyota Safety Sense.
(Image: Toyota)

The lowest level of automation, a vehicle considered Level 1, has some automated features but still requires a person to do most of the work. Level 1 automation means the car has at least one system that helps with steering or braking (but not both), and the driver still needs to be able to take over if something goes wrong.

An adaptive cruise control system that uses sensors to maintain a safe distance between your vehicle and the one in front of it, for example, would be considered Level 1. If a car has automatic brake and steering systems working together, it becomes Level 2.


Level 2 – Partial Driving Automation

kia sorento


The Kia Sorento has the Kia Drive Wise advanced driving assistance system.
(Image: Kia)

Level 2 vehicles have advanced driving assistance systems (ADAS) that can take over steering, acceleration, and braking in certain situations. They work in tandem with one another to perform more complex driving tasks, but still require a human driver to take control should something go wrong or if the vehicle encounters a situation its automated systems can’t handle. 

J.D. Power describes the system(Opens in a new window) as “designed for limited-access highways. It combines adaptive cruise control with stop-and-go capability, leading vehicle distance maintenance technology, a lane-centering assistance system, GPS data, and route information from the navigation system to reduce driver stress and fatigue.”

One example of Level 2 driving automation in action is the Highway Driving Assist feature available in some vehicles made by Kia, Hyundai, and Genesis. For those keeping track at home, Tesla’s Autopilot feature is categorized as a Level 2 ADAS (though there is some debate(Opens in a new window) about whether that is an accurate classification).


Level 3 – Conditional Automation

mercedes-benz s-class


Mercedes-Benz offers its Level 3 Drive Pilot system in the EQS and S-Class outside the US.
(Image: Mercedes-Benz)

Level 3 is much closer to “self-driving” than other levels, with less reliance on a person to pilot the vehicle. Level 3 is called “conditional automation” and pairs assorted driver-assistance systems with AI to handle more complex situations. 

In Level 3 cars, it’s possible to do other things while the car is in control, but you won’t want to doze off or read a book with this level of automation. If the systems fail, the driver still needs to be ready to take over. Rather, Level 3 automation is designed for tasks that don’t require a lot of complex maneuvering, like long highway drives.

Mercedes-Benz’s Drive Pilot(Opens in a new window) system is an example of Level 3 automation. Vehicles equipped with this system can navigate around traffic, detect weather conditions, and merge when lanes of traffic end, automatically. The system is limited to certain geo-fenced areas, however, and only works at speeds up to 37mph. 


Level 4 – High Automation

Waymo One


Alphabet’s Waymo is an example of a Level 4 self-driving car.
(Image: Waymo)

At this level of driving automation, you can kick back with a book while the vehicle drives itself. Level 4 is summed up(Opens in a new window) by the NHTSA as “system drives, you ride.”

Level 4 vehicles are programmed to stop themselves if their systems fail; they’ll usually slow down, pull over, and park. So the person riding in the car doesn’t necessarily need to be ready to take over at all times. In fact, a Level 4 car might not even have a steering wheel or pedals, though many of them do, allowing a driver to take control if needed. The self-driving fleet from Waymo(Opens in a new window), which has been used as taxis in Arizona and San Francisco, qualifies as Level 4.

As of this writing, Level 4 vehicles are used primarily for public transportation services like taxis, and are mostly preprogrammed to drive only within a certain area that doesn’t exceed a speed limit of around 30mph. This means they’re mostly confined to cities for now, though companies like Walmart are using driverless Level 4 trucks to carry products on short routes.


Level 5 – Fully Automated Driving

Level 5 vehicles are fully automated with no need for the driver to do anything but set the destination and ride along. They can drive themselves anywhere under any conditions, safely. There aren’t any Level 5 vehicles sold publicly as of this writing, though they are being tested in multiple countries. So we’re not living in Minority Report yet, but we might be close.

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