Moving people in the age of autonomous vehicles: climate boon or bane?

Driverless Australia

Transport is estimated to contribute to a fifth[1] of Australia’s greenhouse emissions and after energy production, is the key contributor. A radical change in the transport sector, for better or worse, will have profound implications for climate stabilising strategies. Autonomous vehicles are that radical change. But whether they’re a change for good or otherwise really does depend on the policy and regulatory settings put in place to steer change.

What are the threats?

There is genuine excitement at the prospect of being whisked along in fully autonomous cars in the not too distant future. But these vehicles could very well plunge us into gridlock, supercharge urban sprawl and greatly increase transport derived greenhouse gas emissions. Or, at least they have the potential to do so. How come?

Increasing number of trips

The number of car trips may increase dramatically. Car travel will become easier, less stressful and less demanding of drivers. If we don’t need to keep our eyes on the road, we’ll be able to focus on more productive activities while travelling. This may drive stronger incentives to use cars for trips when today we would choose to walk, bicycle or use public transport. Once cars become fully autonomous, there will be a pull away from other transport modes if people can work, be entertained or sleep while travelling in their car[2].

As well, car travel will become more readily available to underserved groups for the first time.  The young, the elderly and the disabled will have the choice to use a car in situations where that choice was previously without the assistance of a licensed driver. Increased mobility for these groups is indeed one of the great promises of autonomous vehicles.[3]

Perhaps most galling of all is the prospect of cars continuing to circle rather than park or travel long distances to find a park. It is a misnomer to call the modern car a driving machine - it’s really a parking machine. The average vehicle is used 4% of the time and parked for the rest of the time[4]. With parking spaces becoming increasingly scarce - not to mention the high prices when it is available - the strong temptation will be to get out of your vehicle at your destination and have it cruise the streets autonomously and unoccupied until you’re ready to be picked up again. Think of it like a permanent school drop off for all of us but on a much wider scale.

Urban sprawl

Our current human-controlled cars have created the urban sprawl we currently struggle with. As Australian car ownership took off in the 1950’s, so urban boundaries expanded.  The very design of our cities shifted away from a focus on people to a focus on cars. A significant portion of the prime real estate in all sizable cities is devoted to the roads and parking spaces needed to service passenger vehicles. Scarce funding needs to be diverted to expensive new infrastructure of all types to provide water, sewerage, electricity and communications as new suburbs continue to spawn. And as quickly as car-focused infrastructure is built, improving car travel, the more people are prepared to live further out and the feedback loop continues.

Autonomous cars have the potential to further feed this process, especially once full autonomy is achieved. If people are relieved from the driving task and can spend time in the car working, for example, they may even be more prepared to endure longer commutes and the suburbs will continue to expand[5].

What are the opportunities?

But these outcomes are not inevitable. If the right path is chosen from the outset, autonomous vehicles could usher in an era of far fewer vehicles on the streets, smart cities designed around people and meaningful reductions in greenhouse gas emissions from the transport sector.

Ride sharing

Significant environmental benefits are likely to be derived from behavioural shifts which come with this transformative technology. One such behavioural shift is car sharing.  Clearly, we have many more cars than we need judging by the amount of time our cars are parked rather than used. But car sharing still faces barriers. People worry that they will be stranded, will have to wait a long time or walk some distance to access a vehicle.

Shared autonomous vehicles offer a solution with users able to call on a distinct vehicle to come to them, thus avoiding searching for the vehicle and walking to it. Further, autonomous vehicles will allow car sharing organisations to reposition the vehicles to best match demand. Where population densities allow it, autonomous vehicles have the potential to transfer cars from an owned asset to a service.

Integration with public transport

One great prize on offer is to integrate ride sharing with mass public transport and solve the ‘first and last’ kilometre problem. In 2012, approximately 7 in 10 people travelled to work or full time study primarily by passenger vehicle and only 16% of Australian’s used public transport[6]. Not being able to access public transport at all or at a convenient time is one of the main reasons stated for not taking public transport.[7] Ride sharing, including automated carpooling, linked with mass transit has the potential to address these problems. Imagine using your personal device, tapping in that you’re leaving work in 10 minutes and heading home. The smart transit system allocates an autonomous mini-van to you and others leaving at the same time, takes you to the train station in time for a scheduled service where your seats are pre-allocated and tracks you to your final station where another purpose-designed single-person autonomous vehicle arrives at the same time as you to transfer you to your door.

Energy savings

From an energy consumption perspective, it’s not clear where autonomous vehicles will end up. With the full suite of sensors, cameras and computer required to operate an autonomous vehicle, there is significant extra weight compared with current vehicles.  The externally-mounted cameras and other sensors also create increased aerodynamic drag. Also significant is the energy consumed by the on board computers and the wireless data transmissions needed for accessing maps for navigation.[8] But going the other way, over time, if the promised safety benefits are realised, a range of heavy safety equipment such as airbags, anti-lock braking systems and laminated glass may no longer be required.[9] Also, there may be less of an emphasis placed on performance, with a preference for smaller engines with less capacity to accelerate. Having removed drivers seeking visceral satisfaction, hard acceleration may become a source of discomfort to be avoided[10].

Looked at in insolation, each autonomous vehicle seems to be a step backward compared with the energy efficiency of the contemporary human-controlled vehicles.  However, autonomous vehicles are predicted to more than make up for these deficiencies when viewed as a system. Once a critical threshold is reached, the computers from many autonomous vehicles, communicating in real-time with each other, are set to deliver smoother, more efficient traffic flow. Benefits will arise from smoother and coordinated acceleration and braking – so called ‘eco-driving’. Aerodynamic drag could be reduced by vehicles operating in platoons and following closely behind the vehicle in front. Optimal route selection, informed by detailed real-time information, should reduce travel times compared with our own ability to make similar decisions. Intersection connectively will also lower vehicle energy usage. Imagine no more waiting at traffic signals and indeed no more traffic signals at all with smart infrastructure efficiently co-ordinating speed and lane usage to shunt autonomous vehicles with known approaches and destinations through the busiest intersections.

Shift to electric powered vehicles

The evolution to autonomous vehicles is expected to bring with it a shift to the predominant use of electric power. Indeed, autonomous vehicles should lower some of the current barriers to adoption of electric power. The ability of autonomous vehicles to travel to charging stations themselves will address the current inconvenience of limited charging stations, long charging times and limited range. If ride sharing becomes important, there should be a drive to high utilisation rates and energy efficiency and the capacity to better amortise the relatively higher capital cost of their vehicles.[11]

This shift will present challenges for the electricity sector. From a greenhouse gas perspective, if the shift to electric cars simply means increased use of electricity generated by burning fossil fuels, the shift will maintain or increase overall emissions. If greenhouse emissions gains are to be secured, it will be critical to ensure the additional electricity required is supplied from renewable sources, whether that is small-scale solar installed by home owners and individual businesses or large scale power supplied, for example, by wind or solar farms.

Important to making such a system work will be complementary development of the electricity, transmission and distribution system. An electricity system with a large proportion of renewable generation sources comes with the challenge of matching supply and demand. The wind and sun dictate when electricity can be generated but demand follows the daily cycle of business and living. The shift to predominantly electric vehicles offers potential mitigants to these challenges. Smart vehicles can communicate with the electricity system and prioritise charging when demand and prices are low. The storage capacity represented by all the autonomous electric vehicles represents a vast electricity storage capacity which could be tapped into if electricity demand peaks above generation capacity and that power needs to be reinjected into the grid. 

In time, we may see smart highways co-evolve with autonomous vehicles to the point where highway pavements and noise barriers are covered with photovoltaic cells and there is wireless power transfer to cars as they travel over the highway[12].

Policy settings

The key takeaway is that autonomous vehicles offer the potential for substantial reductions in energy usage and greenhouse gas emissions. However, these reductions are not assured. They depend on the changes in the way we use our cars, how they are designed and whether the transportation and electricity supply system can be improved with the help of autonomous vehicles. There is also the real risk that energy usage and greenhouse gas emissions could significantly increase, especially if final stage full automation sharply reduces the perceived costs of car travel.

It is important that policymakers consider the environmental consequences and opportunities of autonomous vehicles at the outset before the patterns of use of this transformative technology have been established. Regulators are in a position to facilitate platooning and other ecologically beneficial driving behaviour. Regulations to mandate and standardise vehicle-to-vehicle and vehicle-to-infrastructure communications protocols would be an important step. Once an acceptable safety record is established, regulators need to be proactive in relaxing crash-worthiness standards and allowing vehicle manufacturers to reduce weight by dispensing with safety equipment which is no longer needed. Electricity policy needs to be developed for a future which sees the widespread use of electric vehicles.

Most important, however, will be for policymakers to seize the opportunity to provide strong incentives to establish positive environmental norms of behaviour. Momentum needs to be created in favour of ride sharing and pay for service over vehicle ownership and solving the first and last kilometre problem to increase public transport usage. 

To date, governments throughout Australia have been prepared to bear the political consequences of exposing existing car drivers to the full marginal cost of their transport choices, despite the body of economic, social and environmental studies supporting such a move.[13] The coming transformation in our relationship with the car that autonomous vehicles herald provides governments with a once-in-a-generation opportunity to introduce these polices - before voter expectation and patterns of use are established.

We are at an inflection point in the transport sector and have a unique opportunity to make a critical change. For more than 50 years, Australians have been in love with their cars. Whether it is freedom, status or identity, the car is deeply tied up with our self-image. And as a result, it is a politically high-risk sector to seek to reform. With the introduction of autonomous vehicles, Australians will reinvent their relationship with the car for the first in three generations. The cultural structures will be loosened and the political cost of action will be at its lowest. It is an opportunity which cannot be squandered to make the right turn and drive towards a sustainable future.

[1] Quarterly Update of Australia’s National Greenhouse Gas Inventory:  December 2017 Australian Government Department of the Environment and Energy,

[2] Jason Bordoff, Columbia University’s Center on Global Energy Policy, cited in

[3] Wadud, 9

[4] ‘The Third Transportation Revolution’, John Zimmer, 2018

[5] Wadud, 8




[9] Wadud, 7

[10] Wadud, 6

[11] Wadud, 10 and 11

[12] Hawken (ed) ‘Drawdown. The Most Comprehensive Plan Ever Proposed to Reverse Global Warming’ (2018), location 6125.

[13] See for example Infrastructure Victoria ‘The Road Ahead:  How an efficient, fair and sustainable pricing regime can help tackle congestion’ November 2016


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The content of this publication is for reference purposes only. It is current at the date of publication. This content does not constitute legal advice and should not be relied upon as such. Legal advice about your specific circumstances should always be obtained before taking any action based on this publication.

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