Driverless cars may lead to more traffic congestion: Study

Driverless cars could worsen traffic congestion in the coming decades, partly due to drivers' attitudes towards the emerging autonomous technology, and a lack of willingness to share their rides, according to a study.

Using Adelaide city in Australia as a test model, the researchers surveyed over 500 commuters, including a mix of those who travel to work by car and public transport, and modelled the potential impacts.

"Autonomous or driverless vehicles are likely to have profound effects on cities. Being able to understand their impact will help to shape how our communities respond to the challenges and opportunities ahead," said Raul Barreto, from the University of Adelaide in Australia.

The study, published in the journal Urban Policy and Research, investigated commuters' views on autonomous vehicle ownership and use, vehicle sharing, and their attachment to conventional vehicles.

The team then explored potential vehicle flow, with a mix of autonomous and conventional vehicles, and land use change under different scenarios.

"Our findings show that Adelaide has the potential to significantly reduce the number of vehicles on the roads and improve traffic flows, however these benefits may not be achieved in the near to medium term for many reasons," Barreto said.

"The key factors affecting the transition to autonomous vehicles are commuter attitudes to car ownership and wanting to drive themselves, rather than have technology do it for them, as well as the price of new technology, and consumer attitudes to car sharing," he said.

The research suggests that as riders switch to autonomous vehicles, there will be an adverse impact on public transport.

With most commuters not interested in ride sharing, this could increase peak period vehicle flows, which is likely to increase traffic congestion over the next 30 years or so, the researchers said.

"Under both scenarios we tested, the number of vehicles overall will eventually drop. However, total vehicle trips may increase, and some of the predicted benefits of autonomous vehicles may not eventuate until a lengthy transition period is complete," said Barreto.

The findings have policy implications for how the transition to autonomous vehicles is managed, not just within Adelaide but for other cities around the world, according to the researchers.