How Do Self Driving Cars Work: Complete Guide

Isaac Fernandez

Self-driving cars may have seemed like part of a distant future – one with robots, jetpacks, and life on Mars, but in reality, self-driving cars are already in the advanced stages of development. Self-driven car companies like Tesla, Nissan, Waymo, and Lyft have been honing various models of autonomous cars for years, with some even going as far as to say they’d be ready by 2020. While self-driving cars may not be everywhere on the road yet, they’re well on their way. 

The Benefits of Self Driving Cars

The Benefits of Self Driving Cars

Every year, there are approximately 6 million car accidents in the U.S. Nearly 1.25 million people are killed in car crashes each year worldwide. The main goal of self-driving car technology is to make the roads safer. Self-driving car manufacturers believe that autonomous cars can reduce the rate of human error, which causes about 94% of car accidents. Other goals include reduced traffic, increased convenience, and, hopefully, less pollution. Self-driving cars operating off a clean electric energy grid could be better for the environment than the individual gasoline-powered cars that dominate the streets today. Additionally, self-driving cars could help the elderly or disabled maintain independence and mobility. 

How Do Self Driving Cars Work?

How self-driving cars work is by sending signals to operate the car’s machinery without human intervention. In self-driving cars, cameras and sensors “see” the world around the car and send information back to the car’s internal software, which operates like a GPS. The software maps the world around it and produces the best set of options given the variables at hand. 

Take Waymo, a Google-launched industry leader, and perhaps the best self-driving car, as an example. The Waymo autonomous car uses three methods to send signals to the car’s software: cameras, radar, and laser-emitting LIDAR, which calculates distance. This highly advanced “machine vision” is then translated into driving options by the “deliberative architecture” inside the car’s software. Deliberative architecture is the car’s decision-making capacity or the brain behind self-driving cars. 

The hope of engineers is that the algorithms that control the car’s brain can be set to automatically eliminate unsafe behaviors. For instance, a self-driving car could be set to eliminate certain kinds of angles and turns at high speeds, as the car could calculate in advance that they will lead to an accident – whereas a human brain might not realize in time. 

Semi-Autonomous Cars

Completely self-driving cars might still be in the works, but many cars on the road today operate with some levels of autonomy, measured by scientists on a scale of 0 to 5. 

Level 0

A human driver controls all of the car’s systems. 

Level 1

Certain systems are controlled by the car, but only one at a time. Many cars on the road today are Level 1 cars. Examples of Level 1 technology are automatic braking or cruise control. 

Level 2

The car can work two simultaneous automated functions at once, but needs human intervention at other points. Tesla’s Autopilot function can be considered Level 2 technology.

Level 3

This is also called the “eyes off” level. The car can manage all functions on its own but requires a human driver to take over if prompted. Audi’s 8L is the first car to reach Level 3 technology.

Level 4

This next level is called “mind off” because while a driver is still present, the car can manage everything on its own. In a Level 4 car, the driver could even hypothetically fall asleep. Waymo has reached Level 4 of technology, developing cars that don’t require a licensed driver behind the wheel. 

Level 5

The car is fully automated at every level. Level 5 cars would not have steering wheels or need a human operator at all. This level of technology is still in development, but an example would be autonomous taxis, like those being pursued by Volvo and Uber

While many cars are partially autonomous today, a self-driving car is a car that never requires a human driver to take control, meaning that only Level 5 cars would be considered truly self-driving. 


While engineers hope to make self-driving cars both safer and more efficient than human-operated cars, there are some concerns about this new technology. Heavy rain or snowfall might obscure a car’s cameras from reading lane divisions or road signs. Having too many self-driving cars on the road might also cause the cars’ LIDAR to malfunction. Additionally, how do cars work in tandem with self-driving cars? The rules of the road for autonomous cars remain relatively unregulated

Self-driving cars might also harm the planet and our communities. Self-driving cars could potentially raise energy consumption by up to 200%. By contrast, zero-emissions self-driving cars could reduce energy consumption by 90%. It all depends on how they are made. However, community activists worry that by disincentivizing investment in public infrastructure, self-driving cars pose a risk to lower-income communities, and could cause massive unemployment as people doing driving work would be put out of business. 

Finally, self-driving cars create an ethical dilemma. A person might react randomly or instinctually to a dangerous situation, but a self-driving car would have to be programmed in advance on how to respond. Who decides, and how do they decide, what a self-driving car should prioritize in case of an emergency? The ethics behind this large-scale Trolley Problem are still underexplored, given how many variables can arise on a drive down any road, at any speed. 


Self-driving cars have the potential to save lives, reduce pollution, and make transportation more efficient. They also have the potential to create major ethical, social, and environmental dilemmas. As companies work to develop fully autonomous self-driving vehicles, many cars on the roadway already sport some self-driving features. With the many recent advances in technology, fully autonomous self-driving cars become more likely every day.

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