A close up of a woman in an autonomous car and holding a cup. A self driving car is broadly defined as having technology that senses the conditions around it and can self-adjust.
getty
An autonomous vehicle is broadly defined as one equipped with technology that senses the conditions around it, including traffic, pedestrians and physical hazards and can adjust its course and speed without a human at the controls. The terms “autonomous” and “self driving cars” are often used interchangeably.
However, as defined by the SAE, formerly known as the Society of Automotive Engineers (now SAE International), there are six levels of automated driving ranging from full control of a vehicle by a physical driver, assisted by advanced safety technology, to a vehicle that can operate without any on-board human input. Only that top level represents a driverless, or fully autonomous vehicle.
What Is An Autonomous Vehicle?
An autonomous vehicle is defined by the University of Michigan Center for Sustainable Systems as one that uses “technology to partially or entirely replace the human driver in navigating a vehicle from an origin to a destination while avoiding road hazards and responding to traffic conditions.”
The SAE’s six levels of what it terms “automated” driving ranges from the first three levels (which start with zero), where a driver is behind the wheel and in control, but is aided by various automated warnings or safety features such as blind spot warning and automatic emergency braking.
Levels 3 and 4 represent technology in which the vehicle is self-driving under certain circumstances but may require a human driver to take over.
Finally, level 5 is a fully autonomous, or self-driving, vehicle that does not require a human to operate the controls. This is the only level at which a vehicle is considered fully autonomous.
SAE chart showing six levels of automated driving.
SAE International
How Do Self-Driving Cars Work?
Self-driving cars see what’s going on around them using three main electronic “eyes”—radar, cameras and laser-based LiDar, which stands for light detection and ranging, along with artificial intelligence. They all feed data into on-board processors, using sophisticated software, algorithms and machine learning to send signals to the vehicle’s actuators to trigger appropriate actions such as braking, steering and acceleration.
The array of sensors can detect a wide variety of road features and obstacles such as lane markings, curbs, pedestrians, cyclists or other vehicles. This is done either visually, through cameras, or by bouncing light impulses or radar signals off of surrounding objects. While self-driving automation technologies help improve safety, they are not 100% infallible, and their effectiveness can be diminished when sensors or lane markings are covered by snow or other heavy precipitation.
The Pros and Cons of Driverless Cars
Self-driving vehicles where there is either what’s known as a “safety driver” on board or no driver at all are currently in use, mainly by fleets that include warehouse yard trucks that transport goods from one contained location to another. Companies such as Kodiak Robotics and Aurora now operate self-driving trucks with no safety driver aboard, but may have engineers riding to monitor vehicle performance.
Commercial delivery company Gatik also operates autonomous trucks to bring stock from warehouses to points of sale.
Cab of Kodiak Robotics sixth-generation driverless ready autonomous semi-truck.
Kodiak Robotics Inc.
While Kodiak, Aurora and Gatik run their trucks with no human on board, taxi services such as Waymo and the now-defunct Cruise are examples of when self-driving technology goes awry. Cruise, a former subsidiary of General Motors Co., was forced to shut down its robotaxi service after one of its cars was involved in an accident that injured a pedestrian. In 2018, a driverless Uber robotaxi with a safety driver aboard struck and killed a bicyclist in Tempe, Arizona.
Advantages of Self-Driving Cars
Self-driving cars offer a number of advantages over vehicles requiring hands-on drivers including convenience, access to mobility, efficiency, cost-savings and traffic congestion.
For those incapable of driving due to age or disabilities or without access to conventional methods of public transportation, self-driving taxis and other transit vehicles are seen as a way to provide mobility to get to errands, work or medical appointments. Commercial operators see self-driving vehicles as boosting cost-savings and efficiency because they can run for longer hours without having to stop for meals or breaks, and they require fewer employees.
Cars and trucks with self-driving safety technology called automated driver assistance systems, or ADAS, are already reducing traffic congestion and accidents. A report by the National High Traffic Safety Administration notes ADAS helps reduce traffic accidents because they “assist a driver by anticipating imminent dangers and working to avoid them.”
The combination of reducing traffic jams due to accidents and potentially decreasing the number of vehicles on the road when self-driving transit becomes more prevalent provides promising environmental benefits. A University of Michigan study concluded that when “savings from the driving efficiencies associated with self-driving vehicles are factored into the equation, the net result is a reduction in lifetime energy use and associated greenhouse gas emissions of up to 9% compared to the conventional vehicles.”
Challenges of Self-Driving Cars
The notion of widely available fully autonomous cars relieving travelers from any of the duties and stresses of driving remains fraught with challenges that range from cost to safety concerns. No matter how well any of the technology works, none of it so far emulates human thought, logic or instincts to make split second decisions.
However, taking the human element out of the equation also eliminates distractions or emotions from affecting the vehicle’s operation. For that reason, fully self-driving cars are viewed as potentially safer since the technology is designed to operate the vehicle safely and logically by detecting and reacting to traffic conditions and the route it’s programmed to follow.
That brings up a question of ethics. Since self-driving cars are basically robots programmed to react a certain way in a given situation, they cannot make an ethical decision, for instance, to avoid a collision. Should the car take action to prevent it from striking a person or a group of people? Germany passed a law prioritizing saving human lives over animals.
Serious accidents such as those in California and Arizona have contributed to fear and concern on the part of many communities that would just as soon not have driverless vehicles plying their streets.
Other challenges to wider adoption of self-driving cars include weather, where sensors and road markings could be obscured by snow, sleet or a hard rain. Overall cost remains a major obstacle to private ownership of fully automated vehicles as well. A 2023 study by McKinsey and Company predicts “By 2030, 12% of new passenger cars are sold with L3+ autonomous technologies and 37 percent have advanced AD technologies in 2035.”
The Automakers and Tech Companies Pushing Autonomous Driving Forward
GM’s Super Cruise system can temporarily take over driving on certain roads and during certain conditions. The service is offered on a subscription basis.
Frenak/Cadillac
Right now the highest level of automation available to consumers are systems such as GM’s Super Cruise, Ford Motor Co.’s BlueCruise, BMW’s Motorway Assistant and Tesla’s Full Self Driving—all Level 2. With those systems a driver can temporarily engage the systems to operate the car under certain conditions.
There are several companies building or operating self-driving vehicles for commercial deliveries and robo transit services.
Waymo operates robotaxi service in several U.S. markets.
Getty Images
One of the most successful is Waymo. It operates robotaxi service in 11 markets around the U.S. with plans to expand to 21 more cities including London, UK and Tokyo, Japan.
Partnering with Amazon, Zoox operates robotaxi service in Las Vegas and San Francisco with plans to expand to Miami, Florida and Austin, Texas.
Michigan-based May Mobility operates its self-driving Toyota Sienna minivans with no backup driver aboard in 15 locations in the U.S. and Japan.
Gatik operates autonomous trucks that deliver goods from distribution points to retail locations, while Kodiak Robotics adds its autonomous technology to semi-trucks running long-haul and local routes for such companies as Kroger and Ikea. Swedish tech company Einride’s autonomous electric pods deliver goods in Europe and North America. Pods are driven by remote operators and have no cabs for human drivers.
The Role of AI in Autonomous Driving
Artificial intelligence is playing an increasingly important role in making self-driving vehicles “smarter” and safer.
Through deep learning and computer vision, AI enables cars to better understand their environment and predict the behavior of other road users, according to automotive supplier Valeo, which declared AI “a key driver of mobility transformation.”
Indeed, generative AI has “significantly accelerated the progress of ADAS and AD technologies,” according to a report published June 9 by McKinsey and Co.
The Future of Self-Driving Cars
Consumer appetite for leaving the driving to technology is growing and they’re willing to pay for it, leading automakers to boost ADAS and other automation offerings, perhaps paving the way for fully self-driving cars and trucks to one day be available and affordable for individuals.
Based on consumer interest in automated driving features and commercial solutions available on the market today, in its report, McKinsey predicted ADAS and AD could generate between $300 billion and $400 billion in the passenger car market by 2035.
The world will likely be affected in five key ways, according to artificial intelligence company Allerin: fewer traffic accidents, reduced car ownership, automated logistics including deliveries, improved livability due less noise and air pollution from fewer vehicles on the road and no parking or traffic tickets since autonomous vehicles can pick up and drop off passengers then go on their way.
It’s not certain if all cars will eventually operate without a human behind the wheel and at least partially in control. According to McKinsey, any transition will be at a snail’s pace, projecting that in 2030, only 4% of new passenger cars sold will be installed with level 3 or higher automation functions, increasing to just 17% in 2035.
Don’t discard your favorite driving cap yet. While automakers are rapidly offering more sophisticated automated driver assist technologies, full, self-driving vehicles are likely to remain primarily in the realm of fleets and commercial operators for the foreseeable future.

