Dietmar Exler, chief executive of Mercedes-Benz USA, believes that driverless cars are likely to be 'bullied' by human drivers when the two are sharing road space.

Speaking at a motoring conference in LA, Mr Exler told delegates that it human failings are the main factor slowing the development of self-driving cars - more so than technology, insurance considerations or getting even people to accept the very concept of self-driving cars.

“The real issue is humans,” he said.

While driverless cars will be programmed to be law-obiding and considerate road-users, their human counterparts will be much more aggressive.