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How do self driving cars work?

We’ve heard a lot about driverless cars in the last few years. Most of us know that they’re autonomous vehicles – meaning they can drive without your help – and that taking the risk of human error off the roads would make them a hell of a lot safer. What most of us don’t know is: how do self driving cars work, really?

Driverless cars are one of the most exciting developments in the world of cars, and we’ve looked into it. Here’s how self-driving cars really work: the different levels of autonomy, the features, and the cutting-edge tech behind them.

Self-driving car levels of automation

While we might assume there are only two options: self-driving and regular, non-autonomous driving, it’s a little more complex than that. The Society of Automotive Engineers (SAE) has defined six distinct levels of vehicle automation to help us get a clearer idea of what’s out there.

We’re going to explain how self-driving cars work at each level.

SAE Level 0: Base-level driver support

At Level 0, you are completely in charge of everything to do with driving: accelerating, braking and steering. Your car is fitted with classic assistance features such as cruise control, anti-lock brakes, traction and stability control. However, you also have base-level ‘driver support features’ designed to provide emergency assistance, such as blind-spot monitoring and rear cross-traffic alerts.

Many people are already driving Level 0 cars, which have rear cameras and parking guidance capabilities.

SAE Level 1: A little help from AI

At level 1, self-driving cars are equipped with active driver assistance that helps to lessen the driver’s input towards some driving activities. Adaptive cruise control is a level 1 automation, as are self-parking systems that control steering but not braking and accelerating.

Most cars on the road today are at level 0 or 1.

SAE Level 2: It can drive, but you must supervise

Level 2 is as advanced as cars get as of 2020: even Tesla’s Autopilot series are all SAE Level 2. So, how do self driving cars work at this level?

Level 2 means the car can operate the brakes, accelerator and steering wheel by itself, but you need to keep your hands on the wheel and your eyes on the road. It’s still your responsibility to intervene if something goes wrong, and the car will prompt you to take over if needed.

These cars offer active cruise control with lane centering assistance to enable highway driving. 

SAE Level 3: Grab the popcorn

Up until Level 3, you as the driver are responsible if anything goes wrong – not the manufacturer. This changes at level 3: if the car’s in self-driving mode, the manufacturer is responsible for your safety on the road.

Level 3 self-driving cars can drive completely without you, and you won’t need to pay attention – you could even cue up your favourite show on Netflix.

SAE Level 4: To drive, or not to drive – it’s up to you

Because the responsibility of level 3 is complex (and likely, terrifying for manufacturers), some manufacturers of autonomous vehicles are skipping it and going straight for level 4. 

At level 4, the car is set to drive itself by default, and can drive autonomously in situations it’s been designed for, but you can choose to drive it yourself. So, these cars will still be fitted with steering wheels and acceleration and braking pedals.

SAE Level 5: No wheels or pedals

Level 5 cars are as self driving as they can get. The gold standard in automation, these cars won’t even have pedals or a steering wheel: it’s the driver, and you’re the passenger. 

If it sounds crazy, don’t worry yet – these cars are still a way off in the future!


We can’t make your car drive itself, but we can keep it in good shape. Drop in for log book servicing, repairs, rego checks, or brake specialist services when it suits you – no bookings required!

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