Only California, Florida, Michigan, Nevada, and the District of Columbia have explicitly legalized autonomous technology, mainly to encourage product testing. In the absence of regulations, automakers are pushing forward, arguing that the law must allow what it does not expressly prohibit.

And until something actually goes wrong with a self-driving car, there is nothing that the National Highway Traffic Safety Administration can do to stop automakers from selling them, say experts.

“If someone wants to sell a totally automated vehicle today, you could probably get a court to decide there’s nothing N.H.T.S.A. can do about that until it presents an unreasonable risk to safety,” said an agency spokesman, Gordon Trowbridge, told the New York Times.

And it is likely that computer operated vehicles would cut down on the 33,000 car-related deaths that occur in the US each year, as 90 percent of driving accidents are caused by human error, alcohol, drugs, inexperience, speeding, and wet or icy roads.