Last week, the House approved legislation that would allow automakers to deploy hundreds of thousands of autonomous vehicles on American roads over the next few years.
A similar bill is being drafted in the Senate and is expected to be introduced soon.
Automotive and technology companies have been accelerating their testing of self-driving cars, and have backed legislation exempting autonomous vehicles from current motor vehicle laws.
Some safety campaigners and consumer groups have been critical of the move toward voluntary rules covering self-driving technology, and question whether autonomous vehicles are ready for wide deployment on public roads.
Automakers and government officials contend that the technology could reduce vehicle accidents and traffic fatalities.
The competition to develop self-driving cars has become fierce among auto industry giants such as General Motors and Ford Motor, as well as technology companies including Google and Apple.