Research firm Frost & Sullivan expects that there will be 6m semi- and highly-automated vehicles in use Europe and North America by 2025.

"With BMW and Mercedes-Benz being the first to launch semi-automated vehicles in 2014, we expect close to six million semi- & highly-automated vehicles in Europe and North America by 2025, with a fairly equal split," said Frost analyst Mr Prana T. Natarajan.

"Google is expected to go ahead with an Android-like hardware-agnostic automation module, reaching out a much higher fraction of existing car users, offering the unit as a retrofit," he said.

"Future non-native automotive participants like Google are looking at the needs of future mobility models, which will be based on a user-ship model whereby users hop-on and hop-off into a connected-environment-on-wheels, driven by robotic controls built into the vehicle and providing them end-to-end mobility solutions," Natarajan said.

"This will give drivers the opportunity to spend their commuting time with other activities, such as planning their day or browsing the internet."

A number of manufacturers have said that they plan to introduce autonomous vehicles to market by 2020. Nissan has said it will be ready with multiple, commercially-viable autonomous drive vehicles by 2020.