Autonomous vehicles have been talked about for years, but we still don’t have cars that can fully drive themselves. The reason: self-driving technology is not an all-or-nothing proposition. There are six different levels of vehicle autonomy, as defined by the Society of Automotive Engineers (SAE), which the U.S. Department of Transportation uses for classification.
Level 0 (No Automation)
In Level 0, the driver is completely responsible for operating the vehicle and performing tasks such as steering, accelerating, braking, and changing lanes. Vehicles under this classification can have safety features such as backup cameras and blind spot and collision warnings. An emergency braking system is considered Level 0, as it stops, rather than drives, the vehicle and isn’t sustained over an extended period of time. Most vehicles today fall under Level 0.
Level 1 (Driver Assistance)
Level 1 is the lowest level of automation. At this point, a vehicle has a single automated system for driver assistance, such as adaptive cruise control, which adjusts the car’s speed to maintain a safe distance from other vehicles. The driver is still required to perform other tasks such as steering and changing lanes. A report from the International Data Corporation (IDC) forecasts the number of vehicles with Level 1 autonomy will increase from 31.4 million in 2019 to 54.2 million in 2024. This is a compound growth rate of 11.5% over the five-year period.
Level 2 (Partial Driving Automation)
At Level 2 autonomy, a vehicle's advanced automated system gives it greater awareness of the car's surroundings and can control steering, braking, and acceleration/deceleration. The driver can only take their hands off the wheel for a limited amount of time as the vehicle still requires human supervision.
Recently, Tesla lawyer Eric Williams said the automaker’s "full self-driving" (FSD) software is at Level 2 autonomy. Williams added that the driver must always be supervising the system, as it can't handle situations such as bad weather or road debris. Tesla launched the $10,000 FSD to a limited number of participants in a beta program last October. It plans to make it widely available this year.
Level 3 (Conditional Driving Automation)
The shift from Level 2 to Level 3 is significant from a technological perspective but insignificant from a human perspective. Thanks to "environmental detection" capabilities, Level 3 vehicles can make decisions by themselves, such as overtaking a slow driver. However, they still require human override, and the driver must be paying attention to the road and be ready to take over if necessary.
In March 2020, Honda unveiled its Legend sedan, equipped with Level 3 self-driving technology. It’s the world's first automaker to sell a car with Level driving capabilities. The vehicle's "Traffic Jam Pilot" system can control acceleration, braking, and steering in specific conditions, like congested highways. The car will notify the driver when it needs to return control. If the driver doesn't respond, it will gradually come to a stop, alerting other vehicles via hazard lights and the horn. Honda only plans to sell 100 of these cars in Japan, at $102,000 each.
Level 4 (High Driving Automation)
At Level 4 automation, a vehicle can handle all driving functions and monitor the environment. The biggest difference between Level 3 and Level 4 is that the vehicle can safely stop itself if the automated system fails. Human intervention is only required in specific conditions such as inclement weather (heavy snow), but drivers can still manually override if they wish to.
Waymo, the self-driving vehicle unit of Google’s parent company Alphabet, has been testing its Level 4 technology in Phoenix, Arizona, for several years. In October, Waymo announced it would launch a ride-hailing service that allows passengers to ride the vehicle without a human safety driver on board. (Check out what it’s like to ride in a Waymo vehicle.) Motional, which is backed by Hyundai and Aptiv, has also experimented with Level 4 technology, and in November it received permission to test its Level 4 vehicles in Las Vegas.
A lack of legislation and infrastructure means automakers are only allowed to operate Level 4 autonomous vehicles in limited areas. In California, only six companies – Cruise, Waymo, Nuro, Zoox, Baidu, and AutoX – have received permission to test fully autonomous vehicles (without a safety driver) on public roads. For comparison, 60 companies are allowed to operate autonomous vehicles with a safety driver in the state. In Baidu’s case, it can only test its vehicles on roads with speed limits of 45 mph and can operate day or night but not during inclement weather.
Level 5 (Full Driving Automation)
At Level 5, a vehicle is fully autonomous and no human intervention is required. Level 5 vehicles should be able to operate in every environment, and some won’t have a steering wheel or acceleration/braking pedals.
At the moment, Level 5 autonomous vehicles don’t exist. Due to the influence of factors such as government legislation, public safety, and infrastructure, it’s hard to predict if/when they’ll become ubiquitous — and even when they do become available, people may not feel comfortable using them.
Here’s what some notable names in the industry have said about Level 5:
- Elon Musk — In July 2020, Musk said Tesla was “very close” to level 5 autonomous driving technology and predicted the automaker would have achieved the basic functionalities by the end of the year. As we’ve already covered earlier, this prediction turned out to be wrong as Tesla’s self-driving software isn’t close to Level 5.
- Dara Khosrowshahi — In November 2020, the Uber CEO said fully autonomous vehicles were at least 10-15 years away and regulation would play a huge role in their progress. Khosrowshahi made the comments a few weeks before Uber sold its autonomous vehicle unit to self-driving tech company Aurora.
- John Krafcik — In 2019, the Waymo CEO called Level 5 “a bit of a myth.” He added, “Level 5 means you can drive anything anywhere in any weather conditions, like, you can drive from San Francisco to Santiago, Chile, any time of year, just press a button. This is probably never going to happen. Humans don't even do this."
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