Google started to build automatic driving vehicle

The car will have a stop-go button but no controls，steering wheel or pedals.

Pictures of the Google vehicle show it looks like a city car with a "friendly" face，designed to make it seem non-threatening and help people accept self-driving technology.

Co-founder Sergey Brin revealed the plans at a conference in California.

"We're really excited about this vehicle-it's something that will allow us to really push the capabilities of self driving technology，and understand the limitations，"said Chris Urmson，director of the company's self-driving project.

He added that the cars had the ability to "improve people's lives by transforming mobility".

But some researchers working in this field are investigating potential downsides to driverless car technology.

They believe they could make traffic and urban sprawl（城市擴張）worse，as people accept longer commutes as they do not have to drive themselves.