Skip to main content

IIHS Finds Drivers Misusing Partially Automated Cars As Fully Self-Driving

The Insurance Institute for Highway Safety has published a study showing that most partially automated vehicle users often treat their vehicles as fully automated drivers.


Even as the National Highway Traffic Safety Administration (NHTSA) crashes caused by Tesla's AutoPilot autonomous driving suite, a study by the Insurance Institute for Highway Safety (IIHS) shows that drivers who use the partial automation regularly often treat their vehicles as fully self-driving.

Drivers Ignore Warningswhich I detailed here.

"The big-picture message here is that the early adopters of these systems still have a poor understanding of the technology's limits," said IIHS President David Harkey. "But we also see clear differences among the three owner populations. It's possible that system design and marketing are adding to these misconceptions."

Today’s Automation Have 2 Main Features

Today's partial automation systems have two main features designed to assist highway driving. Adaptive cruise control keeps the vehicle traveling at a set speed, slowing and accelerating automatically to maintain the following distance from the vehicles ahead. At the same time, lane centering provides continuous steering support to help keep the vehicle in the middle of the travel lane. Some systems are also capable of performing lane changes and other advanced maneuvers.

None of the current systems is designed to replace a human driver or to make it safe for a driver to perform other activities that take their focus away from the road. Track tests and real-world crashes prove that today's partial automation systems struggle to recognize and react to many everyday driving situations and road features. Previous research has also shown that the high level of assistance they provide makes it hard for drivers to remain engaged and tempts them to turn their attention to other things.

To determine how frequently users view this budding technology, IIHS researchers surveyed around 600 Cadillac, Nissan/Infiniti, and Tesla owners (about 200 each) who routinely use their vehicle's partial automation system. These systems were selected because they reflect the diversity of designs on the market.

Although all three systems use sensors in the steering wheel to detect when the driver's hands are on it, Cadillac's Super Cruise is designed to allow drivers to take their hands off the wheel for extended periods. In contrast, the other two systems require drivers always to keep their hands on the wheel. Super Cruise uses a driver-facing camera to monitor whether the driver is looking at the road, and as of 2021, Tesla's Autopilot does as well.

The three systems use different methods to recall the driver's attention when it strays, as well as different escalation sequences and fail-safe measures. Only Autopilot and Super Cruise include a lockout feature that disables the system and prevents drivers from immediately restarting it as a final step in their escalation sequences.

ProPILOT Assist allows the driver to make manual steering adjustments without automatically suspending the lane-centering feature. In contrast, Autopilot's lane-centering feature deactivates, and Super Cruise temporarily suspends operation until the driver has stopped steering.

Striking Differences In Their Use

The survey responses also illustrated some striking differences in how the systems' owners use them. Super Cruise and Autopilot users are more likely than ProPILOT users to do things that involve taking their hands off the wheel or their eyes off the road. They're also more likely than ProPILOT users to say they can do nondriving activities better and more often while using their partial automation systems. Similarly, Super Cruise users are most likely, and ProPILOT users are the least likely to say that an activity they think is unsafe to do when the system is switched off is safe to do when the system is switched on.

System design and marketing likely contributed to those differences. TV commercials for Super Cruise focus on its hands-free capabilities by depicting drivers patting their laps and clapping their hands along with a song, for instance. Evoking the systems used by commercial airplanes, the name Autopilot implies that Tesla's system is more capable than it is. In contrast, ProPILOT Assist suggests an assistance feature rather than a replacement for the driver.

Demographics may also have influenced the survey responses. Most Super Cruise and Autopilot owners were male, while both sexes were more or less equally represented among ProPILOT owners. Most Super Cruise owners were over 50, Autopilot owners tended to be younger (a quarter of them were under 35), and ProPILOT Assist owners were more evenly distributed across the age range.

"These results from frequent users of three different partial automation systems once again drive home the need for robust, multifaceted safeguards," said IIHS Research Scientist Alexandra Mueller, the study's lead author and principal architect of the Institute's upcoming safeguards rating program. "Many of these drivers said they had experiences where they had to suddenly take over the driving because the automation did something unexpected, sometimes while doing something they were not supposed to."

Around 40 percent of AutoPilot and Super Cruise users, the two systems with lockout features, reported that their systems had switched off while driving and would not reactivate. Some of those drivers confused a temporary suspension of the feature with the lockout procedure. But those high percentages suggest that many drivers failed to respond to warnings intended to ensure they were paying attention to the road or repeatedly violated the operating parameters often enough to trigger the lockout. On the other end of the spectrum, many ProPILOT Assist users reported that they had never even received an attention reminder.

Most Users Believed Reminders Helpful

Although some drivers who'd received attention reminders said the alerts were at least somewhat annoying, the vast majority said they thought they were helpful and made them feel safer using the technology. Similarly, while a slim majority of the Autopilot and Super Cruise owners who experienced system lockouts said they found them irritating, most agreed that lockouts would also make them feel safer once the purpose of the feature was explained to them.

"The broad acceptance of attention reminders and system lockouts suggests not only that they have the potential to make it safer to use partial automation, but also that they could be implemented more widely to help combat driver distraction in general," said Mueller.

Ford Motor Photo

Marc Stern has been an automotive writer since 1971 when an otherwise normal news editor said, "You're our new car editor," and dumped about 27 pounds of auto stuff on my desk. I was in heaven as I have been a gearhead from my early days. As a teen, I spent the usual number of misspent hours hanging out at gas stations Shell and Texaco (a big thing in my youth) and working on cars. From there on, it was a straight line to my first column for the paper, "You Auto Know," an enterprise I handled faithfully for 32 years. Not many people know that I also handled computer documentation for a good part of my living while writing YAN. My best writing, though, was always in cars. My work has appeared in Popular Mechanics, Mechanix Illustrated, AutoWeek, SuperStock, Trailer Life, Old Cars Weekly, Special Interest Autos, etc. You can follow me on: Twitter or Facebook.