Autonomous vehicles, cars that drive themselves, are coming in the not-too-distant future -- but before that happens, there’s plenty of work that still must be done to make them safe, experts say.

Jim Hedlund, a consultant with Highway Safety North, an organization working with and advising the Governors Highway Safety Association, said when these vehicles begin to appear, there will still be many other cars and trucks being driven by human beings. And the mix introduces some problems.

“All the automated vehicles currently being tested strictly obey speed limits," Hedlund said. "Now the last time you were on an interstate, how many people strictly obeyed the speed limit?”

He said if you have autonomous vehicles strictly adhering to the speed limit, but many other cars being driven by people “going a lot faster on a fairly crowded road, you are going to produce lots of conflict, lots of road rage, and probably lots of crashes.”

Autonomous vehicles also come to complete stops at stop signs, Hedlund said. And he said that's led to crashes where autonomous vehicles were rear-ended by drivers.

A report by the Governors Highway Safety Association suggests making the development of autonomous vehicle safety a top priority.

The report also recommends educating the public, drivers, pedestrians and people who ride bicycles about autonomous vehicles, and what they can and cannot do.

Hedlund said many people believe all autonomous vehicles will completely drive themselves, but at least initially, that will not be the case. He said some autonomous vehicles will only be able to drive themselves on major highways or in certain geographical areas.

“And when the vehicle tells the driver, 'Hey, I can’t handle this. You, driver, must take over,' the driver must do that," he said.

Hedlund said some cars' autonomous cruise control and stay-in-lane technologies have names like "autopilot." But those aren't really complete self-driving functions. The driver has to be ready to take control at any moment.

He said another big issue is coordination of autonomous vehicles with police.

“How does a law enforcement officer on the side of the road flag over an autonomous vehicle and tell it to stop?" Hedlund asked. "How does the automated vehicle pay attention to that?”

He said if an officer or a first-responder comes to an autonomous vehicle on the side of the road, "they have to make doggone sure the vehicle isn’t going to take off on them.”

Another potential problem: If there's a crash, “who is liable for it -- the driver? But there isn’t a driver. The manufacturer of the vehicle?"

He said the bottom line is no one has figured out how autonomous mated vehicles will react to other vehicles operated by humans in unsafe, unpredictable ways.

“We don’t have answers yet and this is something that the manufacturers and developers of automated vehicles really need to get together on," Hedlund said.

He noted fully automated vehicles are already operating in shuttle situations in several parts of the country, including Las Vegas, on the University of Michigan campus and in a retirement community in Florida, but so far there are no fully autonomous shuttle vehicles operating in New Jersey.

You can contact reporter David Matthau at David.Matthau@townsquaremedia.com