The US state of Nevada has recognised the driverless car is no longer part of science fiction.
It has become the first state to issue regulations for the operation of self-driving vehicles, "surely the future of automobiles", said a Nevada transport official.
So how will the driverless car change life in America? University of Chicago professor Robert Bruegmann says it might accelerate urban sprawl.
He says each successive breakthrough in transportation technology in the past few hundred years has resulted in more dispersed, lower-density settlement patterns in almost every urban area in the world.
The railways of the 19th century, for example, grew businesses and population numbers at the centre of large industrial cities at the same time as they allowed urban dwellers to live in ever-more-remote suburbs.