In several U.S. and Chinese cities, you can now hail a taxi with no one behind the wheel. Here’s how self-driving cars work, how close they are to going mainstream, and what’s holding Australia back.
Self-driving cars, also called autonomous vehicles, use a combination of sensors, software and artificial intelligence to drive without human control.
How they work
Most self-driving systems use several types of sensors. Cameras read lane markings, signs and traffic lights. Radar detects the distance and speed of other vehicles. Many also use lidar, which fires laser pulses to build a detailed 3D map of the surroundings.
Software combines all that data to understand what’s around the car, predict what other road users will do, and decide how to steer, accelerate and brake. Detailed maps and huge amounts of driving data help train the systems.
The levels of automation
Engineers describe driving automation in levels, from 0 to 5.
At levels 1 and 2, the car can help with steering and braking, such as adaptive cruise control and lane-keeping, but the driver must stay in control and pay attention at all times. Most “driver assistance” systems sold today, including Tesla’s Full Self-Driving (Supervised), are at this level.
At level 3, the car can drive itself in limited conditions, but the driver must be ready to take over.
At level 4, the car can drive itself without a human in certain areas or conditions. Robotaxis operate at this level.
Level 5 would be a car that can drive anywhere, in any conditions, which doesn’t yet exist.
Robotaxis
Waymo, owned by Google’s parent company Alphabet, runs fully driverless taxi services in several U.S. cities, including Phoenix, San Francisco, Los Angeles and Austin, carrying hundreds of thousands of paid rides a week.
In China, companies including Baidu operate large robotaxi fleets.
Tesla has taken a different approach, relying on cameras alone rather than lidar. It launched a small robotaxi service in Austin, Texas, in 2025, and is developing a dedicated two-seat vehicle, the Cybercab.
Safety
Supporters say self-driving cars could save many lives, because most crashes are caused by human error, such as distraction, speeding and drink-driving. Waymo has published data suggesting its cars are involved in fewer injury crashes than human drivers.
But there have been high-profile incidents, including a pedestrian being dragged by a Cruise robotaxi in San Francisco in 2023, which led to General Motors shutting down that business.
In Australia
Australian law requires a human driver to be in control of a vehicle. Driverless vehicles have only operated in trials, such as automated shuttles.
Australian governments have been working on a national framework, including a new safety law for automated vehicles, to allow them on public roads in future. It’s likely to be some years before robotaxis are common here.
