Cutter Expert San Murugesan says now is the time to examine the potential effect of autonomous vehicles (AVs) on climate change so we can take appropriate steps before widespread adoption is upon us. We need to examine the potential positive and negative environmental impacts of AVs, look at whether they can help reduce the transport sector’s carbon emissions, and consider how we can minimize their carbon footprint as they become mainstream. After explaining the six levels of automation, Murugesan describes several potential AV benefits, including fewer road accidents, making elderly populations more mobile, and solving the last-mile-delivery dilemma with autonomous trucks. After a careful examination of the possible environmental impact of AVs, he offers recommendations for creating an autonomous future that will not only be safer and more convenient, but also better for the environment.
We can’t simply dismiss the idea that autonomous vehicles are going to be a big part of our transportation system.
— Ted Wheeler, mayor of Portland, Oregon, USA1
Transport is integral to business, the economy, and our daily lives. It is currently undergoing significant structural reforms as it moves toward digitalization and decarbonization and is poised for new norms. The automotive sector, a major transport segment, is already seeing major disruptions that impact stakeholders.
Electric vehicles, solar-powered cars, connected vehicles, autonomous driving technology, and ride-sharing services are contributing to this disruption.2 Moreover, there are related disruptions in areas like auto insurance, vehicle registration, and driving regulations.3 Research from CB Insights indicates that driverless cars are likely to transform 33 industries, including healthcare, food delivery, and hotels.4 We are just beginning to see the types of opportunities these changes may bring and the issues they may create, as indicated by detailed, interactive maps available from the World Economic Forum.5,6
As they transition from science fiction to the forefront of transportation technology news, autonomous vehicles (AVs) like driverless cars, vans, buses, trucks, and tractors are becoming our reality. There are still some hurdles, but we’ll see a significant increase in AV design and production over the next five years.7 This will drive change far beyond the auto industry and its allied businesses, affecting our lives and movements and causing unexpected changes in employment and social norms. AVs offer enough benefits that they represent an unstoppable trend that will reshape our world.
Currently, the key stakeholders in this market are autonomous vehicle system developers; private-use, commercial service, and industry service vehicle manufacturers; and users such as car owners, rental car companies, transport companies (bus/shuttle), Mobility-as-a-Service providers, delivery-service providers, and trucking and logistics companies.8
Although widespread commercial and personal adoption of AVs is still a few years away, now is the time to examine their potential effect on climate change so we can take appropriate technical, policy, regulatory, and behavior modification measures. The key questions are:
What environmental impacts will AVs have, both positive and negative?
Will AVs help reduce the transport sector’s overall carbon emissions and address today’s climate crisis?
What can we do to minimize the carbon footprint of AVs as they develop and become mainstream?
These questions are difficult to answer holistically and pragmatically because they involve several interdependent factors. Some factors are currently unknown and may remain so until AVs become mainstream. For example, we may see positive impacts from more efficient driving, better use of shared AVs, eco-friendly smart traffic signals, vehicle platooning, and reduced time hunting for parking in city centers.
There may be negative impacts from changes in driving patterns as well. For example, we may see an increase in vehicle miles traveled because AVs make travel easier and more relaxing (or productive), which could raise greenhouse gas (GHG) emissions. Thus, we must consider AVs’ environmental impact throughout their entire lifecycle, including manufacturing and Scope 3 emissions.9 Further muddying the waters are contradictory qualitative anecdotal claims based on narrow perspectives, rather than holistic ones. Nevertheless, we must attempt to examine AVs’ environmental impact and make an educated assessment based on realistic assumptions.
This article begins with a brief overview of AVs, particularly driverless cars and trucks, then presents a comprehensive view of the environmental impact of the AV ecosystem with new insights on this complex topic. It also looks at current and near-future trends and offers some recommendations.
A Brief Overview of AVs
In automation, robotics, and other domains, the term “autonomous” describes self-governing systems. Specifically, an autonomous system is a machine or system capable of “performing a series of operations where the sequence is determined by the outcome of the previous operation or by reference to external circumstances that are monitored and measured within the system itself.”10 Such a system must be able to sense the environment it operates within and interact with that environment. A system is autonomous if it can attain a set of goals under a set of uncertainties without human or external intervention.11
Key features of an autonomous system are self-operation/governance without human or external intervention, independence, a wide operating range, adaptation to uncertainty, and the ability to achieve set goals. Various types of sensors, the Internet of Things, high-speed communication networks (including 4G and 5G), artificial intelligence and machine learning, data analytics, augmented/virtual reality, high-performance processors, nanotechnologies, and smart signage are all coming together to extend the scope and range of operations of autonomous systems.
Overall, an AV is capable of sensing its environment and moving safely with little or no human input. To perceive their surroundings, AVs synthesize data from a variety of sensors, including cameras, radar, LiDAR, sonar, GPS, odometry, and inertial measurement units.12 Complex algorithms interpret sensory information to control and manage driving and to identify appropriate navigation paths and obstacles.13,14
6 Levels of Automation
SAE International, formerly named the Society of Automotive Engineers, defines six levels of driving automation:
Level 0 (no driving automation). Most vehicles on the road today are at this level.
Level 1 (driver assistance). Vehicles at this level offer driver assistance like cruise control and steering. Adaptive cruise control, in which the vehicle keeps a safe distance behind the car in the front, qualifies as Level 1 because the human driver still monitors and controls steering and the other driving functions.
Level 2 (partial driving automation). An AV at this level has an advanced driver assistance system (ADAS) that may include pedestrian detection, lane-departure warning/correction, automatic emergency braking, and blind-spot detection.15 A human is in the driver’s seat and can take control of the car at any time.
Level 3 (conditional driving automation). These vehicles can detect objects in the surrounding environment and make informed decisions, such as accelerating past a slow-moving vehicle. They require human oversight and have an override option. The driver must remain alert and be ready to take control if there is a problem or danger.
Level 4 (high driving automation). These vehicles can intervene autonomously if something goes wrong or there is a system failure. Cars at this level do not require human interaction in most circumstances, as the autonomous system can intervene in the event of a system failure. However, the human driver has the option to manually override. Level 4 vehicles can operate in self-driving mode.
Level 5 (full driving automation). Vehicles at this level are fully autonomous and do not require human attention. These vehicles won’t have steering wheels or acceleration/braking pedals and will be capable of any action an experienced human driver would take. Fully autonomous cars are undergoing testing in several countries.
These automation levels are the gold standard for industry benchmarking and have been adopted by the US Department of Transportation (DOT). Several companies, including many startups, are competing to get a slice of the fully autonomous future.
The principal benefits of AVs are convenience, comfort, and safety, but there are a number of less apparent benefits. For example, according to a study from the World Economic Forum, self-driving vehicle technology could create a 40% improvement in fuel economy and lower auto emissions.16
Self-driving cars could result in fewer road accidents: there is no risk of drunk driving or driver fatigue, and these cars are expected to make fewer mistakes than humans. They also let people use travel/commute time for work, entertainment, or creative pursuits.17
Self-driving vehicles could make elderly populations more mobile, an important advance as the world’s population ages. Similarly, AVs would enable people who can’t drive a vehicle because of physical or psychological conditions to have an independent means of transportation.
If, as expected, AVs lower the cost of transportation, AVs would improve mobility for those at the low end of the income scale. Some researchers estimate this form of transportation could cost around 50% less than current vehicles.18
AVs could help during health crises like pandemics as well, transporting people while maintaining isolation and sterilization.
Carbon dioxide (CO2) and nitrogen dioxide emissions from automobiles have a major impact on the environment and must be reduced. According to the US Environmental Protection Agency (EPA), a typical passenger vehicle emits nearly 4.6 metric tons of CO2 a year,21 and the World Health Organization estimates that 7 million people are killed annually by outdoor air pollution.22
By 2050, urban mobility systems will consume five times more of the planet’s bio capacities (the ability of a natural area to generate resources while absorbing waste) than they did in 1990, according to Arthur D. Little.23
Clearly, to create a model for safe, clean, affordable mobility that can support the needs of a growing population, we must reduce the overall carbon footprint of transport vehicles. The circular economy is driving the automotive industry to make environmentally friendly vehicles, addressing their environmental impact along their entire lifecycle (production, use, recycling/reuse, and battery/other parts disposal).
The rise of AVs will have a profound effect on the environment, but whether it’s for better or worse will depend on technological and policy choices, energy sources, adoption levels, and usage levels. In fact, the effect of AV adoption on consumer travel patterns may have a greater influence on environmental impact than technical attributes.
AVs could reduce energy consumption in transportation by as much as 90% or increase it by more than 250%, according to a study by the US National Renewable Energy Laboratory.24 That difference matters: more than a quarter of GHG emissions come from the transportation sector, according to the EPA.25
By eliminating the erratic acceleration and braking common to human drivers, AV technology might reduce energy consumption. With more AVs on the road, traffic flows should smooth out, resulting in less energy-consuming, stop-and-go traffic (not to mention less time spent in traffic jams).
Self-driving vehicles, especially heavy trucks, can communicate with each other and form highway platoons. The vehicle at the front of the platoon controls the speed and movement of the platoon; the following vehicles snap together in a single-file line behind the first vehicle and drive themselves safely in close proximity on the highway. The combined aerodynamics of the platoon require less energy to travel along highways.26
By making shared-use vehicles more convenient, AVs could make private ownership less necessary, with users simply summoning a shared-use vehicle any time they need one.
In estimating the environmental impact of AVs, we should consider:
More efficient driving (less fuel/energy consumption) facilitated by AVs that minimize frequent stops and eliminate aggressive driving (i.e., speeding, rapid acceleration, and sudden breaking). Efficient driving can reduce gas mileage by 15%-30% at highway speeds and 10%-40% in stop-and-go traffic.27
Autonomous cars can safely travel faster than human-driven vehicles because they respond much more quickly than even the best human drivers. However, due to aerodynamic drag, fuel efficiency declines rapidly at speeds over 50 mph.28
An overall increase of travel due to faster travel, reduced traffic, and/or more relaxing or productive travel time.
An increase in the popularity of lighter, more fuel-efficient vehicles because accidents are less frequent.
Less fuel wasted hunting for parking in city centers.
Higher occupancy from automated carpooling.
AVs bring the following secondary environmental benefits:
Embodied-energy benefit. In a shared-use model, there would be fewer total vehicles, leading to lower energy for manufacturing and raw material use.
Land-use benefit. With fewer, smaller vehicles on the road, cities could repurpose land currently used for parking and transportation.
Safety benefit. AVs could bring less need for repairs from auto accidents and fewer vehicle replacements.
Interaction with mass transit. AVs could solve the first- and last-mile problem and lower labor costs for transit.29
The AV environmental impact will, in the end, depend on adoption patterns. Cost, reliability, safety, on-road performance, insurance premiums, policy offerings, requirements, supporting transport infrastructure, and local regulations will all influence AV adoption at scale, and it’s not yet clear which of these forces will dominate.
Thorough, pragmatic examination and estimation of the environmental impact of AVs in the next five to 10 years will be complex, as it involves a number of factors, some of which are interdependent (see Table 1). At present, we don’t have suitable comprehensive models containing a quantitative value of determinants. Further studies will be required to gain a better understanding of the disruptive forces of AVs, including how they will be adopted and used, as these patterns may ultimately dictate the environmental impacts of AVs. To model potential AV adoption scenarios and environmental impacts, we need better integration of engineering, social science, and planning disciplines.
Trends, Conclusions & Recommendations
Despite current technical challenges and concerns, AVs are on track to reshape our world. Governments are eager to be seen as winning the technology race in this sector.30 Manufacturers are planning to introduce a variety of AVs, including cars, trucks, tractors, ships, flying cars, and robo-taxis (a driverless car or shuttle bus that can be ordered to your location), and even flying motorcycles. Unfortunately, laws and regulations are lagging AV development rather than leading it.
The rise of AVs is being facilitated by both market push (from large industry players and startups) and market pull (from industrial and individual users). For example, Millennials are more inclined to use AVs than Baby Boomers, especially when they create opportunities for on-demand mobility or ride sharing. On the industry side, autonomous trucks offer the potential for longer operating hours with reduced labor and fuel costs. The resulting cost reductions could trickle down to logistics companies and retailers.
Further research will be needed to fully understand the implications of AV adoption on emissions and environment, roads and intersection capacity, driver and public behavior, and land use, among others. We also need more holistic simulation models to understand the implications of a future where AVs are prevalent. Further studies are needed to determine how to solve current AV deployment challenges.
Nevertheless, we must be cognizant of the challenges inherent in deploying AVs at scale and the transport infrastructure that will be required, including smart roads and compatible signage. Deploying AVs en masse in an environmentally friendly manner will be a huge undertaking.
There are reasons to believe that AVs will help reduce transportation’s carbon footprint. At present, experts (including those in the automotive industry) are uncertain about the overall environmental impact of AVs and driverless driving. We’re hopeful that, on balance, the environmental benefits will outweigh the detrimental factors; of course, only time will tell.
Let’s work toward realizing an autonomous future that will not only be more convenient, safer, and efficient, but also better for the environment.
I’m really looking forward to a time when generations after us look back and say how ridiculous it was that humans were driving cars.
— Sebastian Thrun, CEO, Kitty Hawk Corporation; founder, Google’s self-driving car team31
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10 Antsaklis, Panos J., Kevin M. Passino, and S.J. Wong. “An Introduction to Autonomous Control Systems.” IEEE Control Systems, June 1991.
11 Antsaklis, Panos J., and Arash Rahnama. “Control and Machine Intelligence for System Autonomy.” Journal of Intelligent and Robotic Systems, Vol. 91, No. 1, July 2018.
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13 Lutkevich, Ben. “Self-Driving Car (Autonomous Car or Driverless Car).” TechTarget, October 2019.
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18 KPMG (see 3).
19 Bateman, Kayleigh. “Could Autonomous Trucks Be the Answer to the Global Supply Chain Crisis?” World Economic Forum, 23 November 2021.
20 He, Peng, and Jialin Li. “Could Autonomous Vehicles Put Last-Mile Delivery on the Fast Track?” World Economic Forum, 17 December 2021.
21 “Greenhouse Gas Emissions from a Typical Passenger Vehicle.” US Environmental Protection Agency (EPA), accessed August 2022.
22 Wood, Johnny, and Roderick Weller. “6 Things You Should Know About Air Pollution and Your Health.” World Economic Forum, 7 September 2021.
23 Lerner, Wilhelm, et al. “The Future of Urban Mobility: Towards Networked, Multimodal Cities of 2050.” Arthur D. Little, 2011.
24 Brown, Austin, Brittany Repac, and Jeff Gonder. “Autonomous Vehicles Have a Wide Range of Possible Energy Impacts.” National Renewable Energy Laboratory (NREL), 16 July 2013.
25 “Sources of Greenhouse Gas Emissions.” US Environmental Protection Agency (EPA), accessed August 2022.
26 “How an Automated Car Platoon Works.” US Department of Transportation (DOT) Volpe Center, 11 July 2017.
27 “Driving More Efficiently.” US Department of Energy (DOE) Office of Energy Efficiency & Renewable Energy/Environmental Protection Agency (EPA), accessed August 2022.
28 Brown et al. (see 24).
29 DOE/EPA (see 27).
30 Yergin, Daniel. “How Electric, Self-Driving Cars and Ride-Hailing Will Transform the Car Industry.” The Wall Street Journal, 23 April 2021.
31 Thrun, Sebastian. “Google’s Driverless Car.” TED Talks, 2011.