Autonomous Cars: Levels of Autonomous Driving Explained

Published on 11 May, 2022, 4:57 AM IST

Updated on 3 Jun, 2025, 11:27 AM IST

Team Ackodrive

11 min read

Interesting Articles

Autonomous cars, also known as driverless or autopilot vehicles, may seem like a futuristic concept, especially in India, where traffic is often busy and unpredictable. However, the technology is quickly becoming a reality as automakers continue to develop and test advanced systems. Some premium and luxury cars already offer basic forms of autonomous features. So, how do these vehicles differ from regular ones? Let’s find out.

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Contents

What are Autonomous Vehicles?

An autonomous car or an autopilot car is a type of vehicle that 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.

Key Differences Between Autonomous, Automated, and Self-Driving Cars

There might not be much of a difference between automated and self-driving vehicles. 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 that 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 of ADAS range from 0 to 5. The level begins from cars with no automated driving system to vehicles with complete automated 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 at this level. The ADAS levels 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 levels 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 systems even allow the drivers to take their hands 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 a 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.

Cars with assisted mode: Hyundai Creta, Tata Harrier (with ADAS)

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.

Cars with automated mode: Tesla Autopilot (Level 2.5), Mercedes Drive Pilot (Level 3)

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.

Autonomous vehicles examples: Waymo (experimental), Cruise AV

Advantages and Disadvantages of Autonomous Cars

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

Advantages of Autonomous Vehicle Technology

Below are the pros of autonomous vehicle technology:

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 following 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 is required 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

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 currently no fully autonomous or driverless cars available in India. Fully autonomous vehicles are not yet approved for public road use anywhere in the world. Leading tech companies and automobile manufacturers are still in the testing phase of this advanced technology.

When can we expect fully autonomous cars on the roads?

Autonomous driving technology is progressing quickly, but fully driverless cars may take another decade or more to become mainstream. Widespread adoption will depend on regulatory approvals, infrastructure readiness, and further safety validations.

What is a semi-autonomous vehicle?

A semi-autonomous vehicle requires minimal 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.

Will autonomous cars save fuel?

Yes, autonomous vehicles (AVs) are designed to optimise driving patterns, which can lead to fuel savings. Research suggests that AVs can reduce fuel consumption by 15% to 20% through smoother acceleration, consistent speeds, and reduced idling. If a majority of vehicles on the road were autonomous, studies project up to 18% lower fuel use, 25% reduction in carbon emissions, and improved traffic flow with average travel speeds increasing by 20%.

Are self-driving cars legal in India?

Currently, India does not have specific legislation to permit fully autonomous cars on public roads. The Motor Vehicles Act, 1988, mandates a licensed human driver behind the wheel, which conflicts with the concept of driverless vehicles.

What are the most autonomous cars sold in India today?

While India does not yet offer fully autonomous vehicles, several cars come equipped with Advanced Driver-Assistance Systems (ADAS) that support partial automation. Some of the notable models include:

Mercedes-Benz S-Class: Offers Level 2 features such as adaptive cruise control, lane-keeping assist, and traffic sign recognition.
MG Gloster: Equipped with Level 1 ADAS features like automatic emergency braking and blind-spot monitoring.
Mahindra XUV700: Features Level 1 automation, including lane-keep assist, adaptive cruise control, and forward collision warning.

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