Autonomous vehicles and traffic

The challenge

Of all the transport systems autonomous vehicles are poised to disrupt, private car ownership is likely to be the most affected. What does this mean for a car dominated city like Perth?

In this article

  • Private versus shared autonomous vehicle ownership models.
  • The impacts each model could have on our cities, from traffic congestion to parking demand.
  • How we can use policy to guide us toward a shared ownership model.

Plenty has been written about how autonomous vehicles (AVs) are poised to revolutionise travel. Yet while various studies exist that explore what this means for individual cities, most of these focus on dense metropolises like Singapore. Our context in Australia is different. More than ever, Australians are moving to the fringes of low-density, large footprint cities. The private vehicle remains the only options when it comes to getting around.

This research—conducted by Dylan Melsom, an engineer at Arup—looks at one of those car dominated cities: Perth.

“A fair bit of research has been done on the technology side,” says Dylan. “And there’s been a lot of speculation about when and how AVs will be introduced. But not a lot of that research has looked at things like how parking supply should change, and what that might ultimately mean for the city.”

A significant decrease in parking demand is one of the many benefits we're hoping AVs and shared vehicle ownership models will bring to our cities. Image iStock.

Resilient Resources

Instead of trying to predict what will be, Dylan’s research considers what might be.

“Once we know the range of ways the future might eventually fall, we can attempt to understand each end of the scale and narrow it a bit,” he says. To do so, Dylan considered a number of AV uptake scenarios—from private ownership through to shared ownership models. He then looked at what the impact each model might have on things like transport habits, land-use, and particularly parking supply in Perth.

Any infrastructure that is being planned and built today will have to serve a world with AVs everywhere. Right now the planning process isn’t really considering that.

Dylan’s research suggests there are two extreme views of how AVs may shape our cities. He calls the first scenario 'carmageddon'. Here, AVs are privately owned and sharing is minimal. Empty (dead running) vehicles now share the roadway with commuters and congestion has increased by as much as 50%. A second more desirable scenario, employs vehicle sharing structures in order to minimise private car ownership and the raft of associated benefits

The findings from the research were verified with a number of transport and planning professionals with experience in the city. It was collectively decided that a shared ownership model reflected the best case scenario; a scenario in which less parking can be provided and high-value urban space reclaimed for public benefit.

But what can we do to guide things in that direction?

Dylan decided to focus on policy. He’s drafted up five guiding principles which he believes policy-makers should employ to encourage shared over private vehicles ownership. These include: encouraging stakeholder collaboration; openness and transparency; awareness and education; early action; and flexibility and adaptability.

A shared ownership and use scenario has clear and far-reaching benefits for car-dominated cities. Chief among them is a massive decrease in parking demand, leading to a healthier, wealthier, happier population and a safer, and more environmentally friendly city.

And piece of transport infrastructure being planned and built today will likely serve AVs for the majority of its design life. Dylan believes that the sooner we start designing for that reality, the sooner we can start trying to maximise the benefits that AVs can bring about.


  • There are two extreme end-impact visions of how autonomous vehicles may shape transport and cities of the future. The principle factor dividing the two scenarios is the level of shared AV ownership and use.
  • Based on this range of scenarios, we developed five key principles for guiding policy-making linked to policy goals and concrete actions designed to maximise the potential benefits (namely, a significant decrease in parking demand).
  • Any piece of transport infrastructure being planned and built today will likely serve autonomous vehicles for the majority of its design life. Therefore it is important that we begin designing for that reality now in order to maximise the value that AVs can bring about.

This story was written by Jeff McAllister, as part of the Research Review. This series is produced by the Arup Australasia Research team; Alex Sinickas, Bree Trevena and Jeff McAllister with contributions from Sheda and Noel Smyth.

Lead Arup Researcher

Dylan Melsom
Dylan is an engineer working in the transport planning team in Perth.

Ask Dylan about

  1. The conditions that might lead to a shared ownership versus a private ownership scenario and the effect each scenario might have on a city like Perth
  2. The five guiding principles that can encourage a shared ownership scenario: encouraging stakeholder collaboration, openness and transparency, awareness and education, early action, and flexibility and adaptability
  3. How policy-makers can employ each of these five principles in their policy making decisions in order to maximise the benefits AVs will have on our cities


Research TEAM

Darryl is an engineer working in transport.

Have a problem or a project?

We work with industry partners, governments, universities, startups and community organisations. We do this through research partnerships, and as consultants and facilitators for foresight, research, storytelling and technical writing workshops.

research with us