Study: driverless cars could lead to more traffic

Driverless vehicles could intensify car use, reducing or even eliminating promised energy savings and environmental benefits, a study led by a University of Leeds researcher has warned. Lead author 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, said: "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. That, in turn, may change the transport equation and the energy and environmental impact of road transport." The study concludes that people may stop using public transport altogether, thereby greatly increasing the number of cars on the road.

But traffic jams fall by four per cent as driverless cars can drive closer

Those who can't currently drive, like the very elderly, will

They have been hailed as solution that could finally put an end to congestion on the roads, but self-driving cars may actually lead to an increase in traffic, according to a new report.

Developers of driverless vehicles have long promised the technology could allow traffic to flow more freely, drive closer together and so save energy.

But new research suggests people may ditch public transport in favour of driverless vehicles, increasing the number of cars on the road and energy consumption by up to 60 per cent.

Self-driving cars (the Google car is pictured) were hoped to be the solution to congestion on the roads, but a new report has warned they could actually increase traffic and so gridlock on the roads, even reversing the environmental benefits they promise to bring

The experts made their estimates on the basis that new cars will be fully automated within 20 years.

Up to 10 per cent of traffic increase could be due to elderly people being able to 'drive' for longer, rather than giving up their cars when their sight deteriorates, for example.

Freight could be also shifted from the railways to autonomous lorries.

Speed limits could also be raised as the risk of accidents falls, using up more energy, the report in the journal Transportation Research A predicts.

Associate professor Dr Zia Wadud in the Faculty of Engineering at the University of Leeds, said: '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.

The report said the number of elderly on the roads could increase dramatically as they start using self-driving vehicles. Currently the number of drivers tends to fall off dramatically past the age of 60 (illustrated)

New research suggests people may ditch public transport in favour of this new technology, increasing the number of cars on the road and energy consumption by up to 60 per cent. However, traffic jams (stock image) should decrease by four percent as driverless cars will be able to drive closer together

'That, in turn, may change the transport equation and the energy and environmental impact of road transport.'

He explained that when people make a decision about which transport to use, they do not just consider the cost of a train ticket or petrol, but other factors too.

DRIVERLESS CARS WILL HELP THE ELDERLY Elderly people using autonomous cars could play a role in the predicted increase in traffic. The cars will be a boon for older drivers who can no longer drive – or have never driven - as well as the disabled, the research suggests. After the age of 62, levels of driving worsen as declining ability makes it ‘more risky’. The authors say they do not expect any decline in driving due to ability from drivers in their 60s. The only decline in driving will occur because people die, they suggest. Dr Zia Wadud, associate professor at the University of Leeds’ Faculty of Engineering said: ‘There will be more car journeys from new people [who can’t drive] the elderly and the disabled.’

'Car owners might choose to travel by train to relatively distant business meetings because the train allows them to work and relax,' he said.

'The need to drive is part of the cost of choosing the car, just as standing on a cold platform is part of the cost of the train.

'If you can relax in your car as it safely drives itself to a meeting in another city that changes the whole equation.'

Despite this, congestion levels are expected to fall by up to four per cent, as driverless cars will be able to drive closer together and at higher speeds than conventional cars.

The study looked at how various technologies would impact the US by mid century.

It says that more efficient computer-directed driving styles could lead to a 20 per cent reduction in energy use, while improved traffic flow and reduced jams may lead to a four per cent reduction in energy use.

Cars driving in convoys could create aerodynamic energy savings of between four per cent and 25 per cent while lighter vehicles could save between five and 23 per cent.

There would also be fewer accidents and less emphasis on high performance vehicles, reducing energy use of up to 23 per cent.

Elderly people using autonomous cars could play a role in the predicted increase in traffic. The cars will be a boon for older drivers (stock image shown) who can no longer drive – or have never driven - as well as the disabled, the research suggests

But these very benefits could lead to an increase in the popularity of driving, meaning more cars on the roads and a five to 60 per cent increase in car energy consumption overall.

Assistant professor of civil and environmental engineering Don MacKenzie at the University of Washington added: 'There is lots of hype around self-driving cars, much of it somewhat utopian in nature.

'But there are likely to be positives and negatives.

'By taking a clear-eyed view, we can design and implement policies to maximise the benefits and minimise the downsides of automated vehicles.

'Vehicle automation presents a paradox: it may encourage people to travel much more, but at the same time it makes it practical to implement tools such as road pricing that can offset those effects.