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Autonomous cars: Levels of autonomous driving explained

Team AckodriveJun 6, 2022

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A driverless car may sound like a thing from the future, especially in India, considering the busy and chaotic traffic. But the technology is not a far-fetched idea as the automakers are already exploring ways to put autonomous driving technology into action. You can already find some form of autonomous technology in premium/luxury cars. So, how different are autonomous cars compared to regular vehicles? Let’s find out!

Levels of autonomous driving

What are autonomous cars?

An autonomous car is a type of vehicle which can operate without any human intervention by sensing the environment. The autonomous vehicle eliminates the need for a human to control the car's various functions. It can operate as any other vehicle but without a human driver. 

In other words, it has the capability to drive by itself without any manual inputs. There are different types of autonomous cars depending on the level of autonomous driving. We will touch upon it in the following sections of this article.

Autonomous vs automated vs self-driving: What’s the difference?

There might not be much of a difference between an autonomous, automated and self-driving vehicle. However, there’s a slight difference which is hard to identify since every vehicle that can navigate through stop-and-go traffic, assist in the lane change, and manage speed limits is technically an automated vehicle.

Autonomous, automated, self-driving and driverless cars may sound like the same thing, but they have different meanings. All these terms are often used interchangeably, and culturally it means the same for most people, and that’s okay! But technically, the terms have slightly different meanings, which we will address in this section. Refer to the table below to understand the difference between autonomous, automated and self-driving cars.

Parameters Autonomous Automated Self-driving
Definition It’s a type of vehicle which is capable of operating itself and performing essential vehicle functions without any human intervention. The vehicle is also capable of sensing the environment to perform necessary manoeuvres. An automated vehicle utilises the automated driving system to enable it to respond to external conditions without any human intervention. There are different levels of automation. As the name suggests, self-driving does not require inputs from a human driver under certain conditions (depending on the automation level). They utilise a combination of sensors, cameras and software to navigate the roads safely.
Working An autonomous car can decide on the most efficient route. It can control the lane movement as well. An automated vehicle can only follow orders about destination and route. It can adopt automated driving concepts such as lane assist, adaptive cruise control, etc. A self-driving car can control all or some functions of the vehicle. Driver supervision may be required, depending on the automation level.

What are the levels of autonomous driving?

SAE or the Society of Automotive Engineers, a global association with engineers and related technical experts in the automotive industry, has come up with a classification system that defines the level of automation a vehicle may offer. The levels range from 0 to 5. The level begins from cars with no automated driving system to vehicles with complete automation driving systems. Below are the detailed explanations of each autonomous driving level.

Autonomous driving level Details
Level 0 (Manual driving) The vehicle does not have any sort of automation technology.
The driver has complete manual control over the vehicle, including accelerating, braking, steering, etc.
However, the vehicle may comprise temporary intervention support systems such as automatic emergency braking, stability control, blind-spot warning, lane-keep assist, etc.
The above systems fall under Level 0 as they do not drive the car but only alert/support the driver under certain situations.
For instance, the stability control kicks in to temporarily assist the driver if the vehicle loses traction due to a slippery road surface.
Level 1 (Driver assistance) It is the lowest level of automation with at least one driver support system onboard.
The vehicle may have driver support systems like steering, braking or acceleration assistance.
Despite the support system, the driver remains responsible for controlling the vehicle and should be vigilant in taking control of the car at any given moment.
One such example of a driver support system is adaptive cruise control. It is a driver assistance system that enables the vehicle to maintain a safe distance from the vehicle ahead without any intervention from the driver.
Other features such as steering assistance, lane-following assistance, etc., are also part of Level 1 autonomous vehicles.
However, a Level 1 autonomous vehicle may not have more than one driver support system.
Level 2 (Partial automation) The vehicles are equipped with Advanced Driving Assistance Systems (ADAS) at this level.
The ADAS can take over various vehicle functions such as acceleration, braking and steering under certain conditions.
However, the driver must be alert and supervise the systems at all times.
One of the examples of ADAS is the highway driving assist system, wherein the vehicle can steer, accelerate and brake on its own on highways. However, the driver needs to have their hands on the steering wheel at all times.
Some ADAS systems even allow the drivers to take their hand off the steering wheel on specific highways.
Level 3 (Conditional automation) The Level 3 autonomous driving system takes a massive leap in terms of the driver assistance system.
However, the Level 3 systems are still not road legal across the world.
At this level, the driver assistance systems and AI (Artificial Intelligence) work in harmony to make the right manoeuvres based on the driving conditions around the vehicle.
The driver need not supervise the technology. However, the presence of a human driver is a must and should be alert to take control of the vehicle, especially during an emergency or system failure.
Level 4 (High automation) Also called high driving automation, the Level 4 autonomous vehicle does not require human input.
The vehicle is programmed to stop in case of an emergency or system failure.
Since the vehicle handles all the tasks, a human driver is not required, and it may not have steering and pedals as well.
At Level 4, the occupants can indulge in other activities as there is no need for technology supervision.
The technology can be used in public transport vehicles. Such vehicles are generally programmed to travel from point A to point B.
Level 5 (Full automation) It’s the highest level of automation, and the vehicle can drive on its own in all conditions without any human intervention.
The vehicle can transport people without any human driver.
It’s also not restricted by geographical limits (geofencing) or weather conditions.
The only human interaction with the vehicle is to set the destination.

What are the 3 modes of autonomous driving? 

Below are the detailed explanations regarding the three modes of autonomous driving.

1. Assisted mode

This mode combines the Level 1 and 2 of autonomous driving. The driver gets assistance from the technology but must remain alert and ready to take control of the vehicle at any given time.

2. Automated mode

The automated mode incorporates Level 3 autonomous driving. In this mode, the driver can temporarily hand over the vehicle controls to the system, and during this period, the driver need not supervise the system. However, the driver needs to be ready to take manual control if required.

3. Autonomous mode

The autonomous mode combines the Level 4 and 5 of autonomous driving. This mode completely hands over the vehicle controls to the system. There’s no need for a human driver in this mode as the technology can perform all driving tasks under all conditions. The only human interaction with the vehicle would be to set the destination.

Advantages and disadvantages of autonomous cars

Now you know what an autonomous car is and the levels of autonomous driving. Now, let’s take a look at the pros and cons of autonomous vehicles.

Advantages of autonomous cars

Below are the pros of autonomous vehicles.

  • They can reduce the number of accidents by eliminating human error as the system controls the vital driving parameters. There is no question of distraction or negligence as the system determines every aspect of driving controls.

  • Autonomous cars can also reduce traffic congestion as the vehicles can accelerate and brake simultaneously. The vehicles can also communicate with each other and identify traffic problems in advance to take a detour.

  • They eliminate the hassle of you parking the vehicle. Autonomous vehicles can detect a vacant parking spot and drive there on their own.

  • Autonomous vehicles also provide you with spare time as you need not drive the car. You can utilise that time for other activities such as working or interacting with your loved ones.

  • Autonomous cars make transportation accessible to disabled and senior citizens who might find it difficult to drive cars.

Disadvantages of autonomous cars

Here are some of the cons of autonomous vehicles.

  • One of the significant disadvantages of autonomous cars is the cost. They are expensive due to the high cost of research and development, equipment, sensors, etc. However, the costs may come down in a decade or so with the ever-evolving technology.

  • Autonomous vehicles are not entirely safe as they are prone to system failures and unexpected software glitches.

  • They are also prone to hacking, which poses a threat to the owner’s privacy. Since autonomous vehicles track and monitor the details of the owners, hacking can lead to a breach of personal data.

  • Autonomous vehicles can reduce job opportunities as the drivers may no longer be needed to operate the vehicles. It may have a significant impact on the employment rate and economic growth.

  • Autonomous cars may not function under harsh weather conditions. The sensors may fail, and the vehicle may lose its capability to drive on its own.

What technologies are used in autonomous cars?

An autonomous car is a complex machine that uses a combination of cameras, sensors, radars, lidars and artificial intelligence to travel from point A to point B without any human intervention. Refer to the table below for a better understanding of the same.

Technology Application
Cameras The cameras act as the human eyes and let the system get the visuals of the environment.
Sensors/radars/lidars The sensors, radars and lidars can sense the surroundings of the vehicle. For instance, a radar can help determine the vehicle's speed moving ahead.
Artificial Intelligence (AI) The AI takes care of the execution part by collecting all the data from the cameras, sensors, radars, etc. Apart from that, autonomous cars also utilise technologies such as machine learning and neural networks to form systems that can drive the vehicle autonomously.

Safety of autonomous vehicles

Safety is one of the main concerns when it comes to autonomous vehicles. The below points give you an understanding of the safety challenges of driverless or autonomous cars.

  • Autonomous vehicles need to identify countless objects on the road, from litter to animals to people.

  • Another significant safety concern comes in the form of tunnels, where the GPS (Global Positioning System) cannot penetrate. It hinders the decision-making capability of an autonomous vehicle.

  • An autonomous car needs to make sudden decisions such as acceleration, braking, steering, and sometimes a combination of tasks. It puts a lot of stress on the system, and it can fail.

  • Another challenge for autonomous vehicles is handling emergencies. For instance, the system can fail to detect a sudden lane change or braking from the vehicle ahead and cause a collision.

When is a vehicle fully autonomous?

A vehicle is considered fully autonomous if it can operate by itself without any inputs from a human being in all driving conditions. An autonomous vehicle does not require a human driver and only human interaction happens to enter the destination. An autonomous vehicle can make all the decisions on its own and control all the driving functions without any supervision from the driver.

Frequently Asked Questions (FAQs)

Let’s look at some of the common questions and their answers regarding autonomous cars.

Are there any fully autonomous cars in India?

No, there are no fully autonomous or driverless cars in India. In fact, you may not find a fully autonomous vehicle in any part of the world as they are not approved to ply on public roads. Several tech giants and automakers are still testing the technology.

When can we expect fully autonomous cars on the roads?

The technology is rapidly developing, and autonomous cars could be a reality in another decade or so.

What is a semi-autonomous vehicle?

A semi-autonomous vehicle requires minimum human intervention. It utilises various advanced driver assistance systems to perform different driving functions. However, the driver needs to monitor the system and be ready to take manual control if required.

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