Drivers of semi-automated vehicles regularly ignore safety guidance, US study finds

The Insurance Institute for Highway Safety (IIHS) is an industry-funded group in the United States that aims to pressure carmakers to improve safety standards.

In a new study, the IIHS found that regular users of Cadillac Super Cruise, Nissan/Infiniti ProPILOT Assist and Tesla Autopilot said they were more likely to perform non-driving-related activities like eating or texting while using their partial automation systems than while driving unassisted.

In a survey of 600 active users, 53 per cent of Super Cruise users, 42 per cent of Autopilot users and 12 per cent of ProPILOT Assist users said that they were comfortable treating their vehicles as fully self-driving despite the fact that the features are not designed as such.

Last year, two men being transported in a Tesla who were relying on its Autopilot function died in a crash in Texas, US after the vehicle lost control at high speed on a curve. There was reportedly no one in the driving seat at the time of the incident.

“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.”

Most of today’s partial automation systems consist of two main features that are designed to assist in highway driving.

Adaptive cruise control keeps the vehicle traveling at a set speed, slowing and accelerating automatically to maintain a set following distance from the vehicles ahead. At the same time, lane centring 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 manoeuvres.

But none of the current systems are designed to replace a human driver entirely or to make it safe to perform other activities that take attention away from the road. Previous research has 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.

Although all three systems used by the drivers in the survey contain 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, whereas the other two systems require drivers to keep their hands on the wheel essentially all the time.

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 attention of the driver 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.

The IIHS said their survey illustrated some striking differences in how the systems’ owners use them. Super Cruise and Autopilot users are much more likely than ProPILOT users to do things that involve taking their hands off the wheel or their eyes off the road.

System design and marketing likely contributed to those differences, it added. 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, whereas Autopilot implies Tesla’s system is more capable than it really is.

In contrast, the name ProPILOT Assist suggests that it’s an assistance feature, rather than a replacement for the driver, IIHS said.

Demographics may also have influenced the survey responses. The majority of 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.

IIHS research scientist Alexandra Mueller, the lead author of the study, said: “These results from frequent users of three different partial automation systems once again drive home the need for robust, multifaceted safeguards.

“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 they were doing something they were not supposed to.”