What may be self-driving cars’ biggest problem

Learning to drive a driverless car is more difficult than it sounds. One lab is monitoring how we might react when we have to give up the wheel to a computer.

I am pretty confident in my driving skills, but today my skills as a future car driver are going to be tested. Although it is generally assumed that the introduction of self-driving vehicles is going to make the roads safer, there are still serious doubts about how we humans will adapt to being driven by a robot.

“If you walked past the door you wouldn’t realize there is a full-sized car inside here,” says Dr Anuj K Pradhan, as he shows me into a nondescript office on a upper floor at the University of Michigan Transportation Research Institute (UMTRI) in Ann Arbor, just outside Detroit.

He is right. The room is much larger inside than expected, and in the centre of it sits a normal-looking family hatchback. It is the room that is exceptional, with huge screens wrapping around every wall, ready to drop me into a variety of driving environments on cue. This is going to be an immersive experience, however this simulator is not being used to simulate driving, but to simulate not driving.

“We want to be able to simulate self-driving vehicles to understand human driver behaviour,” Pradhan says. And then catches himself. “Except that they’re not drivers now, they’re non-drivers, or human operators.” Even for researchers working in the field, the rapidly changing world of driverless cars and the terminology that comes with it can be a challenge.

Until we reach a point where cars are self-driving 100% of the time, humans are going to have to resume control in extreme circumstances, when the computer encounters things it can't cope with. Those transitions between computer and human control will become critical.

Sitting behind the wheel, I began to get a feel for the types of scenarios the researchers are studying. I put my foot on the brake, and slide the automatic gear selector into Drive. As we moved off I could feel a vibration and hear the engine noise – all recreated through bass speakers. Driving feels like a cross between reality and a game, and also, at this early stage, fun. I am aware that there are four cameras around the windscreen though, tracking my gaze, so that the researchers know exactly what I am looking at. I feel heavily scrutinised, but I centre myself in the lane, and then press the ON button on the steering wheel.

Dangers of distraction

A female computer voice states “automated mode engaged”, and I relax a little. That moment, and my reaction is exactly what is being studied. At first, it was hard to take my eyes off the road. Decades of driving have taught me that is bad. “Human beings are not used to driving automated vehicles, so we really don’t know how drivers are going to react when the driving is taken over by the car,” says Pradhan.

Will we relax, start texting, have a nap? Or sit with our hands hovering over the wheel, tense, and waiting  to take control? The big promise of automated cars is that we can become distracted when we want to. The danger comes when the human is not concentrating on the road, and the vehicle suddenly wants them to take over. The driver, who has been looking at their phone, may not know where they are, what is around him, or what is happening. He will have to assess all that in seconds and take appropriate action. The irony is that that is only likely to happen in extreme events – in emergencies.

“Driving is a lot about situational awareness,” says Pradhan. You can see what he means for yourself. The next time you are behind the wheel, spend a minute being conscious of all that you are aware of. For example, maybe the car you just went past had a teen driver at the wheel, so you had better keep an eye on them. And the car three ahead of you seems to be braking, so you better be ready to brake as well. There is a police station up ahead – so you become more aware of the speed you're driving.

All of this situational awareness is a picture automatically built over time, not just a snapshot, and it is what you will be missing when a computer voice shouts “autonomous mode disengaged” and you look up to see the back of a truck that you are hurtling towards at high speed. Maybe you will be able to respond quickly enough, but maybe not. You are at a disadvantage. From BBC Future's experience in the simulator, and in other experimental autonomous vehicles such as Google’s cars, it is pretty easy to become relatively relaxed.

A particularly interesting question arises when we think about new drivers. People who get their licences in a few years' time are likely to only have to take control in rare situations, but those situations are going to be the most extreme and dangerous.

“Should we mandate that all drivers should gain five to seven years of driving experience before they can operate a self-driving vehicle?” asks Pradhan.

“Self-driving cars exist, so that is awesome,” he continues. “Technology has made great breakthroughs, but now I think the focus really has to be put on human behaviour – the nut behind the wheel!”

The technology may be ready, but the big question is – are you?

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