A study from the University of Toronto is raising questions about vehicle safety systems that project digital driver alerts on vehicle windshields.

Such augmented-reality, head-up displays (AR-HUDs) are designed to help keep the driver’s eyes focused on the road ahead. The warning message is in the driver’s normal field of vision. Such alerts warn drivers about everything from possible crashes to smartphone activity.

But researchers concluded that these kinds of alerts can potentially divide the driver’s visual and cognitive attention and distract from the primary task of driving. This risk, the study found, is especially pronounced in difficult driving conditions and can lead to what’s known as “inattentional blindness.” 

“Our data suggest that the AR-HUD warning may have an unexpected and unintended consequence – the driver’s attention to the road and traffic is likely to be compromised due to the competition between the normal perceptual processing associated with attending to the road and the need to allocate attentional and other cognitive resources to dealing with the AR-HUD warnings,” the study concludes. “Furthermore, this rivalry for the driver’s attention is most likely to occur when the driving environment is demanding.”

The study was published in the June issue of Plos One. The research project was funded by a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada.

Psychology Professor Ian Spence and students Yuechuan Sun and Sijing Wu designed two tests to measure the impact of AR-HUD warnings on driver attention.