IIHS Report Finds Complacency Hits Drivers Using Automated Driving Technology

The smarter cars get, the dumber drivers act. That’s the takeaway from a new report on distracted driving and automated driving systems from the Insurance Institute for Highway Safety (IIHS). In short, the more people trust autonomous driving technology to safely get them to where they want to go, the more they do something else while “driving.”

In partnership with the Massachusetts Institute of Technology (MIT), the IIHS tested how people behave as they learn to trust automated driving systems. Ten people were given a 2016 Land Rover Range Rover Evoque with adaptive cruise control (ACC) while ten others were given a 2017 Volvo S90 equipped with both ACC and Pilot Assist, which helps keep the vehicle in the center of the lane. The volunteer drivers knew they were being observed while they drove these vehicles for a month between November 2016 and September 2017. The paper was published this month.

You might be able to guess where this is going. While the drivers starting out acting normally and keeping their attention on the road even when these assistance systems were engaged, by the end of the month of driving there was a substantial shift in behavior.

"Drivers were more than twice as likely to show signs of disengagement after a month of using Pilot Assist compared with the beginning of the study," IIHS senior research scientist and lead author of the study Ian Reagan said in a statement. "Compared with driving manually, they were more than 12 times as likely to take both hands off the wheel after they'd gotten used to how the lane centering worked."

One challenge for automotive engineers moving forward is that the better the automated driving systems get, the less engaged drivers become. For example, Volvo upgraded Pilot Assist after the study ended, and the paper notes that a different set of participants grew even more reliant on the improved version. The study authors say an important question to answer in the future is what behavior pattern we will see among drivers who use ever more reliable driving automation technologies.

Earlier this year, Consumer Reports named GM's Super Cruise technology the best automated driving system, in part because it keeps the driver engaged by using direct driver monitoring.

The stakes are high for our understanding of this technology and how it impacts driver behavior. The study concludes that accurate estimation of benefits for partial automation will have to account for the distraction introduced by driver complacency.