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Driverless Cars: Levels of Autonomy

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Don't ask if a car is autonomous, but instead, to what extent it is autonomous.

There's a lot of hype about autonomous cars these days. "This is probably the biggest thing to hit the auto industry since the first car came off the assembly line," said Sen. Gary Peters, D-Michigan, at a 2017 technology conference in Washington. But experts are predicting that the deployment of driverless cars may take longer than many people think.

The truth is that many of these technologies will likely be implemented gradually, and that there are varying degrees of vehicle automation. The computers haven’t completely taken over our cars just yet.

Artificial Intelligence in Automobiles

Is it really the right time to hand over control of our cars to computers? Consider this quote from thinker, author and professor John Haugeland in his book "Artificial Intelligence: The Very Idea": "AUTOMATION PRINCIPLE: Whenever the legal moves of a formal system are fully determined by algorithms, then that system can be automated."

The latest automobiles are already using computers to control various functions throughout the vehicle. As I wrote in a previous Techopedia article "Your Car, Your Computer: ECUs and the Controller Area Network," today's cars may include dozens of computer modules that manage everything from air-fuel ratio to climate control.

So how much autonomy are we prepared to give the vehicles that we drive (or don't drive, as the case may be)? Is it enough to have algorithms in sufficient supply to operate the vehicle without human intervention? These are philosophical questions beyond our current topic. But it is more than a theoretical matter for the family of the cyclist who was killed by an automated Uber vehicle in March of 2018.

Read: Hacking Autonomous Vehicles: Is This Why We Don't Have Self-Driving Cars Yet?


Six Levels of Autonomy

It may come as a surprise to learn that vehicle automation is not an either/or proposition. And not everyone wants complete automation. Putting your car on automatic pilot in fair weather along a standard stretch of highway may be fine, but any driver would want the option to regain control of the car should circumstances demand it. In reality, the autonomy of vehicles is graded on a scale from zero to five, with zero meaning no autonomy and five signifying complete autonomy.

The standards organization Society of Automotive Engineers (SAE) International has defined these levels in a report on "Taxonomies and Definitions" regarding automated driving systems. We will use the SAE descriptions for the levels in the subtitles below. Other organizations with similar standards include the German Federal Highway Research Institute (BASt) and the National Highway Traffic Safety Administration (NHTSA). (To learn more about autonomous vehicles, check out The 5 Most Amazing AI Advances in Autonomous Driving.)

Level Zero: No Automation

Readers who are a bit more experienced know that automobiles didn't always come with all those computerized controls. There was a time when cars had no computers at all, and in the early days they didn't even have power steering or power brakes. At level zero, all aspects of the driving task are in the hands of the driver. Think of the car your father or grandfather may have driven – or even your car if it is an older model.

"A vehicle that fits into this category," says an article from CNET, "relies on a human to dictate every driving action." The driver has full control. Level zero doesn't just apply to an old Ford Model T. CNET offers as an example: "your uncle Rick's 2005 Honda."

Level One: Driver Assistance

At this level, the automobile includes some built-in capabilities to operate the vehicle. The vehicle may assist the driver with tasks like steering or acceleration/deceleration. For several years now cars have been manufactured with controls on the steering column that allow the driver to maintain a constant speed or gradually increase or decrease speed. These functions are enacted by the driver and not automatically performed by the automobile.

Most modern cars fit into this level. If your vehicle has adaptive cruise control or lane-keeping technology, it's probably at level one.

You might be surprised to learn that cruise control was invented by a blind mechanical engineer named Ralph Teetor. Chrysler was the first car company to offer cruise control in 1958 (they called it Speedostat). Later the technology became standard in all Cadillacs.

Read: 7 Autonomous Vehicle Myths Debunked

Level Two: Partial Automation

In 2017, the NHTSA adopted SAE’s six levels in their Automated Vehicles Policy. (They previously defined only five levels.) At this level of automation, two or more automated functions work together to relieve the driver of control. An example is a system with both adaptive cruise control and automatic emergency braking. The driver must remain fully engaged with the driving task, but you will notice the gradual transfer of control from man to machine. NHTSA refers to this as an advanced driver assistance system (ADAS).

Examples of level two include Tesla Autopilot and General Motors Super Cruise. A GM Super Cruise ad says "Bring us your doubts and we'll bring you the future," and calls the technology "the first true hands-free driving system for the freeway." Another is the Mercedes-Benz Distronic Plus, as demonstrated by an owner who seems to have some reservations about its capabilities.

Level Three: Conditional Automation

This level is marked by both the execution of steering and acceleration/deceleration and the monitoring of the driving environment. In levels zero through two, the driver does all the monitoring. At level three, the driver is still required, but the automobile can perform all aspects of the driving task under some circumstances. Levels three and higher qualify as automated driving systems (ADS), according to NHTSA. Another commonly used term is highly automated vehicle (HAV).

There's a big jump in capability between levels two and three. The driver still has to keep his eyes on the road, ready to take over at a moment's notice. But a level three vehicle can handle certain parts of the trip on its own – mainly highway driving. An example of this level is the Audi AI traffic jam pilot, whose technology is demonstrated in this video.

Read: Hybrid vs. Autonomous Engines – What's Better for Development?

Level Four: High Automation

Level four vehicles don't need a human driver. The vehicle can essentially do all the driving, but the driver can intervene and take control as needed. This level of automation means that the car can perform all driving functions "under certain conditions." The test vehicles currently on the road would fall under this category.

Waymo LLC (once known as the Google self-driving car project) is testing level four vehicles. An article from DesignNews, "Autonomous Cars Will Move to Level 4 in 2018," says that new sensor technology from Velodyne Lidar amounts to "a huge step forward" for autonomous cars. But they say that level five is still a decade away.

Level Five: Full Automation

A completely automated vehicle can perform all driving functions under all conditions. In this situation, humans are just passengers. But as CNET authors Kyle Hyatt and Chris Paukert tell us, "It's hard to imagine a world where Level 5 autonomous vehicles become the norm, available to all. If that happens, how would that change the way that we live?"

One writer for The Atlantic speculates that fully automated cars could result in free transportation for everybody – with a catch. Judith Donath pictures a world where a free driverless car will chauffeur you and your family across town, so long as you stop 15 minutes or so at a sponsor's store. She thinks that "targeted stops" at places like McDonald's, Starbucks or a bookstore would be enough to entice the advertisers to pay for the ride.

Of course, we already have automated transportation in some places. Have you ever been to an airport that shuttles passengers from one terminal to another without a driver? Such automation is being considered for other mass transit systems to take the place of buses and taxis in town.

Watch: VIDEO: 3 Key Breakthroughs That Paved the Way for Artificial Intelligence

Controlling the Future

Full automation is already a reality in some industries. Manufacturing plants employ robotic arms and automated processes to complete everyday tasks on assembly lines. Driverless tractors plow, plant and harvest the fields on today’s high-tech farms. And the piloting of commercial airlines is nearly all done automatically these days. Ceding control of our private vehicles is another matter. How quickly and how completely that will happen remains to be seen. Some people just love to drive – sophisticated algorithms notwithstanding. Why should we be asked to stop now?


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David Scott Brown
David Scott Brown

Throughout his career, David has worn many hats. He has been a writer, a network engineer, a world traveler, a musician.As a networking professional, David has had a varied career. David started out troubleshooting frame relay and x.25 with Sprint, and soon moved to Global One, the international alliance with Deutsche Telekom and France Telecom. Since then, he has worked for many national and multinational network providers and equipment vendors, including Sprint, Deutsche Telekom, British Telecom, Equant (Global One), Telekom Austria, Vodafone, o2/Telefonica, ePlus, Nortel, Ericsson, Hutchison 3G, ZTE, and Huawei.As a writer, David's portfolio includes technical articles, short stories,…