The pros and cons of driverless cars

Driverless cars could change the way we travel, work and organise our lives – but while the pros will bring substantial benefits they may not outweigh the cons for energy use, according to new research by scientists from the University of Leeds, University of Washington and Oak Ridge National Laboratory.

The research, presented in an Energy and Mobility Futures policy briefing, has made headlines in the press (Yorkshire Post, Western Daily Press), tech blogs (Gizmodo, Tech Mic) and online news sites (Climate Change News, The Conversation, Discovery News) and was published in the journal Transportation Research Part A. It was led by Dr Zia Wadud, Associate Professor in the University of Leeds’ Faculty of Engineering and a research group leader in the University’s Institute for Transport Studies.

“There is no doubt that vehicle automation offers several efficiency benefits, but if you can work, relax and even hold a meeting in your car that changes how you use it,” Dr Wadud said. “That, in turn, may change the transport equation and the energy and environmental impact of road transport.”

Efficiency gains identified by the team included up to a 20% reduction in energy use from more computer-directed driving and as much as a  25% aerodynamic savings from automated cars driving together closely in formation (called “platooning”). Improved safety from reduced crash risk could also allow significantly lighter cars to be built. However, this could be offset or even overturned by the popularity of the vehicles, which could prompt a move away from public transport, increase traffic congestion and encourage demand for heavier, faster autonomous cars, raising emissions.

Writing for The Conversation, Dr Wadud pointed out that the impact will also depend on how the concept of ownership evolves, with an on-demand, car-sharing culture potentially compensating for some efficiency losses, while tailoring car size to trip and number of occupants also offers valuable savings. There is, he said, potential for self-driving cars to encourage a switch to electricity, further reducing emissions. This had not been studied in great detail but, given the unpredictable outcomes for self-driving cars, “It’s vital that we find and implement ways to realise the full energy-saving and carbon-reducing potential.”