The human touch: Why our safety drivers keep their hands on the wheel
By Simon Tong
Right now, human safety drivers are a crucial component in the safe development of autonomous driving systems. At FiveAI, as we mature our technology and increase its ability to safely navigate our cities, our safety drivers act as instructors to our learner driver technology. Human drivers intervene to maintain safe operation when our vehicles encounter a situation they can’t deal with. Through this process, we’re able to capture valuable data which we analyse in forensic detail and learn from, to further advance our tech.
For the time being, then, safety drivers have the tricky and unusual job of ‘driving without driving’. Like regular drivers, they still need to pay attention at all times. But they must do so without controlling the vehicle directly when it’s in autonomous mode. If you’ve watched a demo of a driverless vehicle, you’ll likely have seen a human safety driver in action. And they were probably waving their hands, without touching the wheel, to clearly demonstrate the fact that they’re not driving.
This ‘hands-off’ approach isn’t how our safety drivers operate, though. At FiveAI, we train all our safety drivers to keep both hands lightly on the steering wheel.
Here’s why we take the ‘hands-on’ approach:
It’s faster and safer
We hypothesised that, if we followed the ‘hands-off’ approach, in an emergency valuable time would be lost waiting for safety drivers to return their hands to the steering wheel. We then put this hypothesis to the test. At our test track, we ran back-to-back trials comparing the hands-on and hands-off approaches.
When we surprised our safety drivers by injecting unexpected steering, braking and acceleration faults, we found that the two approaches often meant the difference between the vehicle staying in lane and straying outside of it. As we anticipated, safety drivers who had their hands off the steering wheel — even just a few centimeters away — were not reliably able to bring faults under control fast enough. If our safety drivers had to respond to such hazards on a public road, this lost time could lead to a collision with the kerb or oncoming traffic, endangering the driver, any passengers, pedestrians, and other road users.
For this reason alone, the hands-on method is clearly crucial. But there are other reasons why ‘hands-on’ is the safe, responsible way to go.
It focuses the mind
I mentioned that safety drivers have the rather unnatural challenge of ‘driving without driving’. When your hands are on the wheel, you feel more like you’re ‘driving for real’. Many of our driving instincts are interwoven with the basic mechanics of the driving task. We look where we’re steering and we steer where we’re looking. A hands-on approach helps our safety drivers maintain full situational awareness and stay focused on monitoring the road scene outside the vehicle, so they can detect and respond to unexpected hazards before they develop.
Driverless vehicles will soon be part of city-dwellers’ daily lives. But, for now, the industry is busy testing, learning, optimising and, most importantly, ensuring safety. Let’s be clear — these vehicles are not yet able to handle every scenario a human driver can. Complex traffic problems, tyre blowouts, damaged road surfaces and other situations are currently outside of our system’s ‘operational design domain’. That’s why human safety drivers are a necessity right now, and why they must expect the unexpected, and be poised to take control of the car at any time, seamlessly.
Ensuring optimum focus for our drivers is especially important because, as autonomous systems become ever more capable, the need for a human safety driver to intervene decreases. As safety drivers find themselves intervening less and less, the risks of task underload and inattention creep in, and must be countered.
Hands ‘feel’ the road
Any driver is able to ‘feel through the wheel’ and identify when something’s not quite right. As seasoned experts, our safety drivers’ instincts are even sharper. Their brains are hardwired to the mechanics of driving, and their hands are attuned to the subtlest of signs — they’re constantly gathering information from the wheel. This haptic feedback gives them added confidence that the vehicle is performing as expected, as well as early warnings of unexpected situations and behaviours. The driver can then take control before a scenario or fault becomes dangerous.
And when they do take over, because they’ve been following the steering wheel with their hands, they’re able to regain control with far more precision than if their hands had been away from the wheel. Ergonomically, they’re all set up. There’s no need to ‘snatch’ at the wheel. This smooth, seamless transition is far safer than the alternative hands-off style, which could lead to loss of control when trying to take over manually.
While the hands-on method may not look as futuristic and impressive to passersby, it’s safer. And safety is what matters. Our drivers’ speed of re-engagement, enhanced focus, and ability to ‘feel the road’ are supporting us in keeping all road users safe while we evolve FiveAI’s autonomous driving system.
By staying in touch with the steering wheel, we’re staying in touch with safety.
Simon is FiveAI’s Safety and Human Factors Manager. Most often found at our Millbrook test track location, Simon brings 15 years of road safety expertise to the development of our autonomous driving system. He has built our operational safety management system, which covers everything from driver training to our comprehensive Safety Case.
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