When each state wrote its driving laws, a car that drove itself wasn’t a consideration. Back in 2012, University of South Carolina assistant professor of law Bryant Walker Smith took on the daunting task of reading the traffic codes in every state to find legal provisions that could complicate or prohibit self-driving cars.

He basically found only one, a provision in New York state that says, “no person shall operate a motor vehicle without having at least one hand … on the steering mechanism at all times when the motor vehicle is in motion.”

Beyond that, Smith said he found pretty much zero unambiguous red flags, prompting him to title his research paper “Automated Vehicles Are Probably Legal in the United States.” And even that New York law, he says, is open to interpretation because it could be argued that, with a self-driving car, no “person” is actually driving it, so therefore there is no conflict.

But that’s not to say states aren’t busy enacting legislation related to autonomous cars. According to Anne Teigen of the National Conference of State Legislatures, 32 bills related to self-driving cars have been introduced in 2016 or are still active from last year’s carryover.

Nevada was the first state to authorize the operation of self-driving cars, in 2011, and since then five other states plus Washington, D.C., have passed legislation. And Arizona’s governor signed an executive order directing agencies to support the testing and operation of self-driving cars.

The bills have ranged from authorizing the use of self-driving cars on public roads—under certain safety and testing conditions—to defining what a self-driving vehicle is to requiring a licensed driver in the driver’s seat. North Dakota simply asked for a study of autonomous vehicles, and Tennessee’s bill prohibits local governments from banning their use.

Despite the debate, Teigen says no state has introduced legislation that specifically prohibits the testing or development of self-driving technology, although Smith argues some have certainly muddied the waters.

For now, the federal government seems to support the move toward autonomous cars. Transportation Secretary Anthony Foxx recently said he was “personally asking automakers to submit more regulatory interpretation requests so that we can work with your progress, not hold it back.”

That means systems such as Tesla’s Auto Pilot and Cadillac’s Super Cruise are legal to use, except in New York state. Because those types of systems are not considered self-driving (the driver needs to pay attention), the driver rather than the automaker will be responsible in the case of an accident. Things are less clear concerning what will happen once fully self-­driving cars are on the road. Already, Volvo has gone on record saying it will assume liability when an accident is caused by a Volvo running in fully autonomous mode, as long as the system isn’t being abused.

Editor's Note: This article also appeared in the May 2016 issue of Consumer Reports magazine.