Drivers are more likely to stay engaged and maintain control when their partial automation system allows cooperative steering, according to a study released by the Insurance Institute for Highway Safety (IIHS). The research highlights significant behavioral differences between users of systems that enable minor manual adjustments and those that deactivate when the driver intervenes.
“These results suggest that small differences in system design can nudge drivers toward safer habits,” said IIHS President David Harkey.
Partial automation systems, which assist with lane centering and speed regulation, require drivers to stay alert and ready to take over. However, the study found that systems designed with cooperative steering -- where the driver can make minor steering adjustments without deactivating the system -- lead to more proactive driver behavior.
In an online survey of 1,260 owners of vehicles equipped with partial automation, including Ford, General Motors, Nissan/Infiniti and Tesla models, researchers observed that drivers of cooperative systems were 40% to 48% less likely to take their hands off the wheel in high-stress scenarios compared to those using non-cooperative systems.
“Those are sizable differences,” said Alexandra Mueller, senior IIHS research scientist and lead author of the study. “Systems that deactivate upon manual steering input may discourage drivers from intervening because reactivating the system is often cumbersome.”
The survey also revealed widespread misconceptions among participants about how their systems operate. Despite stark differences in system responses, many respondents believed their systems remained active during manual adjustments when they did not.
To test drivers' behavior, participants viewed highway driving scenarios, including calm conditions and situations involving a pickup truck towing a trailer. When passing the steady trailer, drivers with cooperative systems were 26% more likely to steer within the lane, rising to 29% when the trailer was weaving.
“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,” Mueller said.
