California is the latest state to take up legislation that would set rules for self-driving vehicles, a technology that has grown so quickly that few places have any regulations addressing it.

Bills dealing with autonomous vehicles has been introduced this year in Arizona, Florida, Hawaii and Oklahoma, according to the National Conference of State Legislatures. Last year, Nevada became the first state to open the door to autonomous vehicles after it passed a law directing the state transportation department to establish standards for the machines.

As it stands now, in most places, autonomous vehicles are in murky legal territory. "In California, like most states, current law doesn't prohibit them," says state Sen. Alex Padilla. "Current law doesn't allow them. When current law was written, no one envisioned them."

His legislation takes an approach similar to that of Nevada and instructs the California Highway Patrol to develop rules for autonomous cars. He says he choose that approach, rather than create the regulations themselves, since he believes that the agency has the most expertise.

Google, the Internet giant, is testing an autonomous car that rely on lasers, cameras and radar, among other technology, to drive themselves, and the company reports that to date, they have traveled more than 200,000 miles safely throughout California, though Google technicians remain in the car when they're on auto-pilot. (It's worth noting that there's some debate whether a Google car involved in an accident last year was being driven by an employee or in automatic mode.)

Proponents of autonomous vehicles say that, in addition to being convenient for riders, the technology will help reduce the number of accidents on the road

The military is examining the technology, as are car companies, and Intel Corp. this week announced it's creating a $100 million investment fund to pump money into companies developing technology for autonomous vehicles.

While some consumer vehicles have semi-autonomous functions -- like automatic parallel parking and warnings when driver stray from lanes -- there aren't any self-driving cars available for consumers yet.

When that day comes, the technology will raise a host of legal issues: Who’s at fault if such a vehicle malfunctions and causes a collision? What type of insurance should it have? Can a passenger who’s been drinking – but technically isn’t driving – get charged with a DWI? If a car violates traffic laws, who gets the ticket?  Can someone with a suspended license operate an autonomous vehicles?

Padilla tells Governing that it's important for his state to get in front of the issue, given California's position as a tech hub.

But the legislation hasn't been a slam dunk everywhere. Earlier this year, state Rep. Jeff Dial of Arizona introduced a measure similar to the one in California and Nevada requiring his state's transportation department to develop rules for the vehicles.

At a hearing last month, his fellow lawmakers shot down the proposal in a matter of minutes, arguing that there isn't an imminent need for the rules, so it would be unwise to spend time and resources developing them now.

But Dial says it's an important issue to consider. Self-driving vehicles would make lives easier for the elderly who have difficulty driving, and if Arizona became a leader on the issue, it could see an economy benefit by being a hub for testing, Dial reasons.

He says he plans on introducing legislation addressing with autonomous vehicles next session and will have meetings with stakeholders over the upcoming year.

So far, it doesn't appear that the federal government is addressing the policy implications of autonomous vehicles, says Jaime Rall, a senior policy specialist for transportation issues at the National Conference of State Legislatures.

The issues that involve autonomous vehicles -- safety standards, liability and vehicle registration, among others -- are typically under the purvey of the states. That means it will likely be the states, not the feds, who take the lead on regulating the technology, she says.