Breaking Down the Levels of Autonomous Driving

August 27, 2022

Team ACV




Breaking Down the Levels of Autonomous Driving

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A man in his car as it navigates traffic, demonstrating the levels of autonomous driving

This content has been reviewed and updated on April 19, 2024.

The idea of self-driving vehicles has become increasingly popular in recent years, and for good reason. Levels of autonomous driving are not just science fiction—they’re rapidly becoming a reality. The degree to which a vehicle is autonomous varies greatly, leading the Society of Automotive Engineers International (SAE) to develop levels to differentiate the capabilities. They defined six self-driving levels, each with its own limitations¹. On the lower end of the spectrum, autonomous features focus on assisting the driver through alerts or momentary interventions. At the high end are fully intelligent self-driving cars of the future dreamt up in pop culture.

In 2024, we’re already seeing vehicles hitting mid to high levels of automation in real life. Let’s look at the various levels of autonomous driving as well as the features you might see at those respective levels. 

What Are the Levels of Autonomous Driving?

Level 0: No Driving Automation

Level 0 is aptly named since it defines vehicles without driving automation features. Driving is a key word here, as this level is specifically about the human being in full control of the vehicle. Some features that assist the driver are still accepted under this level, such as lane departure systems that warn the driver if they’re drifting, or electronic stability control (ESC) systems. Automated emergency braking (ABS) systems are also considered part of Level 0 automation. Since features that alert the driver to danger or only provide a momentary intervention don’t eliminate the driver’s roll or reduce it significantly, these still fall within Level 0.

Level 1: Driver Assistance

In 2024, vehicles with Level 1 features are commonplace. These features can help control speed or steering, but not both at the same time. Adaptive cruise control is a good example, allowing the vehicle to keep a safe distance from other cars and trucks by slowing down and speeding up as required. Lane-keeping features that stop the car from drifting out of the lane are also considered Level 1 technology. These features help the driver but never significantly remove the human from the operation of the car.

Level 2: Partial Driving Assistance

This level of autonomous driving requires features that can control steering and speed at the same time within some boundaries. These types of features are generally categorized as advanced driver assistance systems (ADAS). Self-parking systems, for example, allow a vehicle to use sensors to maneuver and accelerate itself to get into position. Perhaps one of the best-known ADAS systems is Tesla’s autopiloting feature. With a destination selected on its integrated touchscreen, the vehicle can automatically brake, accelerate, switch lanes, and activate blinkers. However, these examples still require the driver to be alert and present so they can take over the driving if there’s any issue with the automation’s decisions or if there are obstructions the software doesn't recognize. 

Level 3: Conditional Automation

Similarly to the previous levels, conditional automation still requires an alert and ready driver. However, conditional automation starts introducing some “decision-making” abilities to the vehicle in terms of monitoring the environment with sensors, such as cameras and lidar, and using that information to navigate through various traffic and road conditions. Mercedes-Benz has experimented with Level 3 automation with their Drive Pilot system. There are limitations to its abilities, however, including limiting the vehicle’s speed to 40 mph or under, requiring a vehicle ahead to follow, and needing ideal road conditions. The route must also be mapped ahead of time, so the utility of the system is still limited. While we’ll likely see Level 3 automation become more prevalent in the future, the technology is still maturing.

Level 4: High Driving Automation

The Level 4 autonomous driving system takes a leap into no longer requiring human intervention. Vehicles at Level 4 are able to drive themselves around in a majority of situations and conditions without issue. They are smart enough to recognize hazardous road conditions or unsafe weather and mitigate those dangers by slowing down or pulling over. They may also utilize geofencing, which defines an area in which they’ll operate and doesn’t allow the vehicle to travel outside those bounds. This level of automation is found in driverless taxis that are tested and operated by Waymo and Cruise in San Francisco². Imagine hailing a taxi to find no one sitting in the driver’s seat because there is no need for a driver. This is what these companies are working to make commonplace. With all passengers and no driver, Level 4 starts feeling truly futuristic.

Level 5: Full Driving Automation

The highest self-driving level is similar to Level 4 but with greater versatility. A Level 5 autonomous vehicle is not restricted to specific conditions or only allowed to operate within specific, tight bounds³. Level 5 vehicles don’t yet exist, but they are the prize many companies are trying to get to. Vehicles reaching Level 3 and Level 4 of autonomous driving are already becoming reality, so as science-fiction as this may sound, Level 5 self-driving may be closer than we think. In the meantime, we’ll likely see more vehicles with Level 3 and Level 4 autonomous capabilities first. 

Stock Future-Proof Vehicles with ACV Auctions

Cars with automation are attractive to consumers looking for vehicles with cutting-edge technology—and they’re willing to pay for the added level of convenience and cool factor. Be ready to serve those customers by stocking your dealership with reliable cars that have the tech features they want. 

If you’re in the market for vehicles with self-driving features, join ACV Auctions. Not only do they have years of expertise to help you find the autonomous features you want most, but they also boast a robust inventory to match your needs. Every vehicle is fully inspected and vetted with a detailed market report, so you can be confident about your bid.



  1. Taxonomy and Definitions for Terms Related to Driving Automation Systems for On-Road Motor Vehicles. SAE.  Retrieved April 11, 2024, from
  2. Ludlow, E. (16 August 2023). Paid Driverless Taxis Are Slowly Becoming a Reality. Bloomberg. Retrieved April 11, 2024, from
  3. Self-Driving Vehicles. EPA. Retrieved April 11, 2024, from