It is something that has long been suspected. Now, we’ve evidence from a new study, once the Autopilot self-driving tech is enabled on Tesla cars, human drivers tend to pay less attention to what is happening on the road.
The study highlights the awkward in-between phase that we are now in: Self-driving tech become good enough to handle many aspects of staying on the road, but cannot be relied upon to take over everything, all of the time.
That is potentially more dangerous than both fully human driving & fully automated driving, because when people get behind the wheel, they assume they do not need to give their full attention to each part of the driving experience, as this study shows.
“Visual behavior patterns change before & after Autopilot disengagement,” write researchers in their published paper. “Before disengagement, drivers looked less on road & focused more on non-driving related areas compared to after the transition to manual driving.”
“The higher proportion of off-road glances before disengagement to manual driving weren’t compensated by longer glances ahead.”
As capable as it is, at instant Autopilot is unable to drive a car on its own in every scenario. Tesla itself says that Autopilot is “designed to help you with the most burden-some parts of driving” which its features still “require active driver supervision and don’t make the vehicle autonomous“.
As a part of an ongoing study on driving & advanced technology, researchers from the Massachusetts Institute of Technology (MIT) analyzed driver posture & face position to determine where their eyes were focused. Using data collected since 2016, team compared 290 incidences of drivers switching-off the Autopilot feature, comparing their behavior before the dis-engagement with their actions after.
Data across almost 500,000 miles (over 800,000 kilometers) of travel was used for the study.
Of the off-road glances observed, while Autopilot was enabled, most were focused on the large screen at the middle of the dashboard in every Tesla automobile. The researchers found that 22% of those glances exceeded 2 seconds with Autopilot switched on, compared with only 4 percent with Autopilot off.
Off-road glances were longer on average while Autopilot was engaged. During manual driving, glances to side windows, side mirrors and car mirror were all more likely. The researchers even developed a simulation model to estimate glance behavior across a wider set of data.
“This change in behavior might be caused by a misunderstanding of what the system can do & its limitations, which is reinforced when automation performs relatively well,” write MIT researchers.
The team suggests that autonomous systems, like Autopilot should be watching drivers also the road, showing warnings & adjusting system behavior depending on how attentive the human behind the wheel is being. Right now, Autopilot uses pressure on wheel to judge whether-or-not someone is still paying attention.
It is also important to form drivers fully aware of what self-driving tech can & can’t do, the researchers say. While Tesla tells drivers that some attention remains required, it does call its latest software update Full Self Driving, which it is not .
The latest study does not make any link between span & safety, so there are not any conclusions to be drawn here about whether-or-not Autopilot is more or less safe than manual driving. what’s clear is that it makes drivers pay less attention to the road.
“The model in this case can enable new safety benefit analysis through simulation, which can inform the policy making process and design of driver support systems,” conclude researchers.
The research has been published in Accident Analysis & Prevention.