Study: Partial Driving Automation May Be Teaching Drivers Wrong Behaviors

A child reaches for a hot stove, a parent slaps their hand away — that’s how learning happens. According to a new study from the Insurance Institute for Highway Safety, similar methods teach similar lessons in semi-autonomous vehicles, such as Teslas with Autopilot engaged or Cadillacs using Super Cruise. The agency’s research suggests that drivers using partially autonomous driving technologies that disengage when they make steering corrections are less likely to grab the wheel in tense situations than those whose systems remain engaged with driver input.

Slap the hand away, the child stops reaching for the stove.

Related: Study: Most Automaker Partial Automation Driving Systems Need Improvements

The study looked at four current partial-automation technologies: Ford’s BlueCruise, GM’s Super Cruise, Nissan’s ProPilot Assist and Tesla’s Autopilot. There are many differences between the four systems, but this study focused on one meaningful distinction: how the system reacts to steering inputs while engaged.

Ford BlueCruise and Nissan ProPilot Assist remain operational when the driver makes steering corrections within the vehicle’s current lane, which is known as cooperative steering. Meanwhile, GM Super Cruise and Tesla Autopilot switch off their steering assistance when the driver makes any adjustments, requiring the driver to reactivate the system to resume operation. Interestingly, one system from each camp — ProPilot Assist and Autopilot, respectively — requires the driver to keep their hands on the wheel, but those two systems’ react in opposite ways when that hand is more than dead weight. (The latest versions of Nissan’s ProPilot Assist, 2.0 and 2.1, allow for hands-free driving, but a sufficient number of owners were not available for the survey.)

Fundamental Misunderstanding

To study driver behavior, IIHS surveyed 1,260 owners of vehicles equipped with these driver aids. The agency’s first conclusion is that drivers often believe their cars allow cooperative steering even when they don’t.

Participants were shown a video of a vehicle driving semi-autonomously in which the driver manually steers from one side of the lane to the other, after which the vehicle resumes semi-autonomous operation. Respondents tended to think their systems stayed on and continued to help steer when they executed a maneuver like the one in the video — even when they didn’t.

Furthermore, IIHS found that when drivers are aware their car does not allow cooperative steering, they’re less likely to provide steering input in situations where it might be wise to do so. For this portion of the study, participants were shown three more videos, all from the point of view of the driver of a vehicle operating semi-autonomously. The first video was a baseline, showing the vehicle traveling down a road with no other traffic on a clear day. In the second, the subject vehicle was in the left lane of a highway, approaching and passing a truck pulling a trailer with its wheels crowding the center line. The truck and trailer also starred in the third video, except this time it was weaving, veering in and out of the right lane before finally stabilizing with the tires on the center line as the subject vehicle passed. Study participants were asked if they would put their hands on the wheel and provide any steering input in each of the three scenarios.

Misplaced Reliance

That last study showed the starkest example of what happens when drivers are discouraged from taking the wheel. In the baseline scenario with a clear road, drivers with systems that allow cooperative steering and those with uncooperative systems were similarly likely to keep one or both hands on the steering wheel. When passing the steady truck and trailer touching the line, however, those with cooperative systems were 40% more likely to say they would keep their hands on the wheel. Rather than take control when the situation appeared more dire with a weaving truck and trailer, drivers without cooperative steering were even less likely to do so. Drivers with cooperative steering were 48% more likely to keep their hands on the wheel when the truck and trailer were weaving than those without it.

These findings touch on the critical psychological component of autonomous driving systems. As significant as the technological challenges are in developing these aids, the question of how their human drivers interact with them is just as important.

“These findings suggest that cooperative steering may have an implicit influence on how willing drivers are to take action when the situation calls for it regardless of how they think their system is designed,” said Alexandra Mueller, the study’s lead author and a senior IIHS research scientist.

Room for Growth

In households with vehicles from two different brands, driver expectations for system operation and capabilities leave even more room for potentially dangerous misunderstandings. Semi-autonomous driving technology is here and increasingly prevalent but, as this study and others suggest, there’s a long road ahead before drivers can tune out completely.

More From Cars.com:

• IIHS Begins Evaluating Semi-Autonomous Technology
• First Test: What It’s Like Using Mercedes-Benz’s Drive Pilot Automated Driving System
• Consumer Comfort With Autonomous Tech Trails Automaker Advances
• IIHS: Pedestrian Detection Systems in Most Mid-Size Vehicles Fail After Dark
• Autonomous Driving Levels and What They Mean to You

Related Video:

Cars.com’s Editorial department is your source for automotive news and reviews. In line with Cars.com’s long-standing ethics policy, editors and reviewers don’t accept gifts or free trips from automakers. The Editorial department is independent of Cars.com’s advertising, sales and sponsored content departments.