Sky Schaudt/KJZZ

An Uber self-driving car in Tempe in 2017.

STEVE GOLDSTEIN: A 49-year-old woman died after she was struck by a self-driving Uber car on Sunday night. Elaine Hertzberg was walking a bike across Mill Avenue. She was not in a crosswalk. The company has since confirmed the car was in self-driving mode with a safety driver behind the wheel. Early investigations show the car was going around 40 miles an hour with no signs of slowing.

LAUREN GILGER: As the investigation continues it includes questions that you don't normally ask after a regular car accident. Ronald Elcock is with the Tempe Police Department.

RONALD ELCOCK: "We're looking at any technology that may have been in place on that specific vehicle or any technology that may have been in operation on that vehicle at the time. And that's going to tell us a lot more information.

GILGER: This morning I spoke with Dr. Srikanth Saripalli, associate professor of mechanical engineering at Texas A&M University. His research includes autonomous vehicle safety — and just a quick note that his research is funded by some car companies looking into this technology, but not by Uber. I started by asking him whether self-driving cars are safe at this point to be tested on real roads.

DR. SRIKANTH SARIPALLI: The answer right now is: We don't know. So the reason for that is that the way car testing and car manufacturing has worked in the United States, at least and now, is that the regulators, the federal regulators have always kind of relied on the manufacturers to tell them that the cars are safe, right? You know, typically if you see something bad happening with seatbelts or with steering wheels or things like that, then you get a recall. But that was OK before because we had drivers, and drivers were always tested before they could actually drive.

GILGER: Yeah.

SARIPALLI: That's not the case now, right? So because if you just believe in the manufacturers, they are both making the car but also, in a sense, making that drive us.

GILGER: ... I know you you work with this technology and you know a lot about, that but without getting into kind of the weeds of how that technology works, I wonder, sort of, what was supposed to happen when something like this that is unpredictable that is caused by human error happens? Like when there's a woman who is not in the crosswalk. And what is the car supposed to do?

SARIPALLI: So, I mean, 'What would a human do?' is probably what we should kind of think about, right? If you take the median driver, so which means that, I'm a decent driver, and I'm probably not the best driver, but I'm also not the worst driver. So, I'll try to break, but I might also swerve right so I might actually give it a very large stealing angle so that I can swerve the obstacle and then go into it differently. So I'm going through a strongly which is I'm going to lean for the incoming traffic, and then I can go back into my own lane, right? So, that usually is not possible right now when you have the self-driving cars. So, they follow the rules of the law but they don't think about if something bad is happening, maybe we should be doing something different.

GILGER: Right. You should break the rules.

SARIPALLI: Yes. Right? I mean, so if you see somebody the wrong-way driving, almost all self-driving cars would right now brake and stop, right? They wouldn't think of going into the incoming lane so they ... don't get hit by the wrong-way car.

GILGER: So is the technology assuming, though, that everything else around it on the road will also follow the rules? Like that eventually we will be living in a world where everything on the road will be a self-driving vehicle and then things will flow?

SARIPALLI: Yes. So I tell this to my students. If everything, if every other car were self-driving then the problem is already solved, right? The technology's not assuming that. But right now the technology, I don't think is ready for large-scale public deployment. And I think almost every company knows that.

GILGER: Yeah. What about the role of the engineer behind the wheel? So our governor here in Arizona just issued an executive order this month that allowed testing of these vehicles without a safety driver even. But if there is a driver behind the wheel, I guess to monitor to check things, what's supposed to be the role of that person?

SARIPALLI: Well, the role of that person is to make sure that if they see something that they cannot understand and the person is supposed to take over, right? But the person, the engineer, also has some reaction time. And those reaction times had actually much higher than what a computer will have. So if it is really something that the vehicle cannot see, then the person probably already cannot react to it because it's probably already too late.

GILGER: So, do you think it's important then that an engineer is behind the wheel when we're testing these vehicles right now?

SARIPALLI: Oh, absolutely.

GILGER: So, do you see this winning in the near future where self-driving technology kind of makes all of our roads safer because it gets rid of this human error — but also can adapt to the human error that will inevitably happen around it?

SARIPALLI: I think so, but I think there's a lot of work to be done before we get there. So I sincerely believe that it will happen very quickly. But I think we do need a lot of testing, and one of the ways to test it to share data between all the manufacturers. So and that is important because if you're driving and nothing else is happening — while the data is useful for getting the autonomous vehicles to say 90 percent or 95 percent — when something that you have not expected happens, that is the data that is a lot more important, so that you can get to that 99 percent.

GILGER: Dr. Srikanth Saripalli is an associate professor of mechanical engineering at Texas A&M, whose research includes an autonomous vehicles. Dr. Saripalli, thank you so much for your time this morning.

DR. SRIKANTH SARIPALLI: Thank you.

GILGER: Uber declined a request for an interview but in a statement said: "Our hearts go out to the victims’ family. We are fully cooperating with authorities and their investigations of this incident."