Autonomous Car Levels 0 to 5 – What They Mean

In an effort to standardize autonomy levels in self-driving cars, the Society of Automotive Engineers International, or SAE, developed a six-stage numbered summary that outlines various stages of technological development. Each level has a number 0 through 5, with higher numbers indicating an increased level of autonomy in a vehicle. These numbers may appear on a company’s marketing materials, in a popular news article or in a press release about a new offering from a car company.

Check out what each self-driving car level means, and discover what to expect from a rapidly approaching future where autonomous cars are the norm.

Self-Driving Car Level 0: No Automation

Driver: Licensed driver with full attention and total control
Vehicle: No automation

At level 0, you have complete control over your car or truck. You steer, accelerate, brake, activate the turn signals and honk the horn. Your car may offer warnings, such as an audio alarm when you back up and get to close to another car, but you must apply the brake to prevent hitting the other vehicle.

Self-Driving Car Level 1: Driver Assistance (“hands-on”)

Driver: Licensed driver with full attention required
Vehicle: Semi-automated systems, like cruise control.

Level 1 means your car controls either the steering or speed, but not both at the same time. The most common applications at this level are adaptive cruise control or parking assistance. Adaptive cruise control changes speed on your vehicle when the car’s laser technology senses other vehicles ahead. It’s your job to steer away from any obstacles. Adaptive cruise control happens at high speeds. Parking assistance occurs at very low speeds when you try to squeeze into a parallel parking spot. Your car takes over steering and senses the vehicles on either side, but you have your foot on the accelerator and brake.

Self-Driving Car Level 2: Partial Automation (semi-“hands-off”)

Driver: Licensed driver with full attention required
Vehicle: Semi-automated systems, like steering, speed and braking.

This semi-“hands-off” level indicates that your car has control over speed, steering and braking. Avoiding an accident and watching out for hazards is still the job of the driver. On some SAE Level 2 cars, you must keep your hands on the steering wheel to show that you are ready to intervene at any moment, such as when you should change lanes, slam on the brakes or make a turn. Think of Tesla Autopilot, Volvo Pilot Assist or Cadillac SuperCruise for Level 2. As of 2019, these features are becoming more mainstream.

Self-Driving Car Level 3: Conditional Automation (“eyes off”)

Driver: Licensed driver with ability to take control, if required
Vehicle: Primary driving functions are automated under some conditions.

At Level 3, you can turn your attention to other things in certain conditions at lower speeds. On your commute to work, you can text, watch a movie or get some work done on the way to the office. The car alerts you when it enters a situation where you need to pay full attention, such as during bad weather or when there are no stripes on the pavement. Audi pioneered this level with its A7 prototype. A few years later, the 2017 Audi A8 Luxury Sedan was the first commercially available car to achieve this level with its Traffic Jam Pilot. The car can take complete control over driving conditions in slow-moving traffic up to 60 kilometers, or 37 miles, per hour.

Self-Driving Car Level 4: High Automation (“mind off”)

Driver: No Licensed driver required (passengers OK)
Vehicle: Primary driving functions are automated under most conditions.

Your car has complete control and can even drive without a human present. This level of automation is limited to a certain geographical area and low speeds. Think of automated fleets of taxis or cabs that pick up and drop off people in the middle of a downtown area or on a college campus. These cars may not even have steering wheels or pedals on the floor because the vehicle fully controls these aspects. The only limitations on speed and location are set by the software instructions embedded in the car.

In late 2017, Waymo (an off-shoot of Google) announced that autonomous mini-vans are about to create a ride-sharing service in Phoenix. People can hail a vehicle, get in, and arrive at their destination without controlling the car whatsoever. No one can take over the car and joy ride outside of a particular geographic range, and this is the highest level to hit the road for ordinary people as of February 2018. This level is highly convenient as it saves large companies money because they don’t have to hire taxi drivers to deliver basic services. Plus, this level of automation increases productivity because automated cars don’t need rest breaks for human drivers.

Self-Driving Car Level 5: Full Automation (“chauffeured”)

Driver: No Licensed driver required (passengers OK)
Vehicle: Primary driving functions are automated under all conditions.

The car has complete control over every situation. There are no limits to speed or location, but the car must follow all traffic laws, hazard signs, weather conditions and safety protocols. Waymo is developing 600 Chrysler Pacificas for this level of capability. At the highest level of automation possible, this is the goal Google aimed for when it began its autonomous vehicle research in 2009. Automakers are completely on board with this type of system because autonomy saves lives and saves money.

What’s Next?

Nationwide standards, security systems and safety protocols must be in place for widespread adoption of this technology across the entire United States. Despite any legal drawbacks, it’s only a matter of time before everyone can climb into an autonomous vehicle, tell it where to go, and then go to sleep on the journey there. You may see this type of driving in select cities and urban centers as early as 2019 when a new frontier in driving becomes a reality for thousands of drivers.

Cars with Autopilot Today

Interested to know which cars have Autopilot (self-driving) features today? See our Cars with Autopilot article.