CAVs and the environment: Looking into the future

The Environmental impacts of Connected and Automated Vehicles project assessed the expected national environmental impacts as a result of increased vehicle automation and connectivity. The project’s final report and literature review are both available for download below.

The research was conducted between 2024-25 by RMIT University’s Centre for Urban Research, iMOVE and the Department of Infrastructure, Transport, Regional Development, Communications, Sport and the Arts.

Key findings

• The study confirmed that connected and automated vehicles (CAVs) will have a mixed environmental impact; while they can improve efficiency through eco-driving and shared transport, but they also risk negative outcomes like urban sprawl and increased emissions if left unmanaged. Positive outcomes will depend on their application across different modes of transport and favourable outcomes may require policy intervention. For example, shared public use models are anticipated to be more environmentally sustainable than private ownership of CAVs.
• The study identified research gaps such as: a lack of real-world and Australia-specific evidence with the current knowledge being mainly theoretical; minimal separation of the unique environmental impacts of automation versus connectivity, and a lack of research identifying the additional environmental effects of CAVs compared to those achieved from the shift to electric vehicles (EVs).
• The study highlights the importance of pursuing Australian research and trials to generate real-world data, while simultaneously developing a proactive national policy framework that prioritises CAV usage that achieves optimal positive environmental outcomes. See below for further project findings.

Background

CAV technology continues to be developed and tested around the world and in Australia. As a result, CAVs are expected to be added to the vehicle mix on Australian roads, which will have significant environmental impacts, in addition to safety and accessibility benefits. Current research identifies some of these impacts, but research gaps remain, especially in the Australian context.

The Environmental Impacts of Connected and Automated Vehicles project investigated the environmental impacts of the expected introduction of CAV to Australian roads in two stages:

1. Stage one investigated how transitioning from conventional vehicles to CAV would impact transport systems and the environment. Based on literature review and analysis, it explored the potential positive and negative environmental impacts of CAV at the vehicle level, transport system level, and urban system level, across the major CAV implementation models. This stage also identified critical knowledge gaps and under-researched issues and suggested opportunities for future research to better inform government policy and decision-making.
2. Stage two was an assessment of the policy implications of the various impacts and attempts to quantify the findings through an expert survey group consultation. This policy analysis drew on 16 factors identified in the stage one report, covering the three levels discussed in stage one. The different factors were linked to possible regulatory and policy tools and six scenarios were then developed to explore possible CAV use scenarios by 2050.

Further findings

In addition to the key findings outlined above, the project report also found:

• Most of the expert survey group respondents believe there will be low penetration of CAV in the Australian motor vehicle fleet by the year 2050 (up to 40%), noting connected vehicles are expected to arrive earlier than full CAV. This means the major impacts from CAV are unlikely to be seen until after 2050.
• There will not be significant environmental impacts with CAV uptake below 50%, as the fleet is not large enough to maximise benefits or externalities. This highlights the need for Government policies to be forward thinking about what type of transport and urban future are desired and implement policy settings to support the realisation of that future.
• At the vehicle level, the greatest positive environmental impacts can be seen in scenarios which permit eco-driving, limit speed and place design regulations or policies on vehicle manufacturers.
• At both the transport and urban system levels, the greatest positive environmental impacts can be seen in scenarios which ensure that CAVs operate in a way which complements, rather than competes with, public transport, while limiting private use.
• At the urban system level, the greatest potential for negative impacts is associated with ubiquitous and unregulated use of CAVs. Allowing highly deregulated production and use of CAVs has the potential, if met with high uptake, to increase the energy use of motor vehicle transport, the number of trips and vehicle kilometres travelled, and undermine public and active transport.

The policy scenario analysis undertaken illustrates the great potential for CAV to have very positive, or very negative environmental impacts, depending on the uptake, policies and regulations implemented. As part of this work, six scenarios were developed, exploring possible CAV use by 2050:

1. Deregulated with high CAV uptake
2. Deregulated with low CAV uptake
3. Regulated with high CAV uptake
4. Regulated with low CAV uptake
5. Highly regulated with high CAV uptake
6. Highly regulated with low CAV uptake

Conclusions and further work

In order to maximise positive environmental benefits from the deployment of CAV, policy makers and regulators need to develop clear forward-looking policies, policy settings and regulations to support their vision of the type of transport and urban environment they envisage for the future.

To support this approach, it is recommended that further research is undertaken in two main areas:

1. Disaggregate the environmental impacts of CAVs from the emissions reductions offered through the increased uptake of electric vehicles; and
2. Disaggregate the environmental impacts due to vehicle automation from those that are a result of high levels of vehicle connectivity.

Download the reports

Download your copy of the final report and literature review by clicking the following links:

• Environmental Impacts of Connected and Automated Vehicles (CAVs) – Stage One report: Comprehensive Literature Review of Environmental Pros and Cons Impacts of Connected and Automated Vehicles
• Environmental Impacts of Connected and Automated Vehicles (CAVs) – Stage Two report: Assessment of Policy Scenarios