But with the wrong policy settings, the technology could undo those savings by putting more cars on the road, discouraging public transport and encouraging urban sprawl.
Researchers at RMIT University released the findings from a two-part study into connected and autonomous vehicles, while warning regulators to consider road rules for robotaxis now, before they take off in Australia.
The research comes after Uber announced plans to expand its autonomous vehicle service into more nations, and after Google-owned Waymo held talks with the NSW government about road tests.
The connected and automated vehicle study, conducted by RMIT and funded by the iMove Co-operative Research Centre, reviewed existing data about the environmental impact of smart vehicles, and assessed regulations that could apply to them.
It identified a long list of potential positive and negative outcomes from the technology, ranging from more efficient rides to more cars on the road.
On the positive side, autonomous cars could cut energy consumption by 15 per cent due to economical driving, the study found, as well as reducing traffic, requiring fewer car parks, and lowering the number of privately owned cars.
But the vehicles could also use more energy if allowed to travel at faster speeds, could discourage people from using public transport and encourage longer car journeys.
Autonomous vehicles would also give more people access to private transport, RMIT sustainability and urban planning lecturer Liam Davies said, which could increase the cars in use.
"Currently people who are going out for a drink, they can't drive a car … but an autonomous vehicle would allow people who can't drive, like drunk people, to drive," he said.
"You can see how this logically starts to increase the amount of kilometres travelled on our roads."
Researchers investigated six policy scenarios to manage negative impacts, and found some of the biggest risks were allowing the private use of self-driving cars, letting them compete with public transport, and driving without passengers.
Australian regulators were already considering self-driving car safety laws, Transport Department connected and automated vehicle policy director Darren Atkinson said, but should consider environmental impacts with them.
"This is the time for us to come together to consider how do we tackle the environmental bits," he said.
"You can't do them in isolation, they need to be part of a package considering the social benefits."
On March 12, Uber announced a partnership with Wayve and Nissan to bring self-driving cars to Japan as part of its global expansion, and Google-owned Waymo has approached the NSW government about testing its vehicles locally.
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