Cognitive Distraction: Something to Think About

Abstract

Distracted driving, though not a new phenomenon, has attracted significant attention in recent years due to the proliferation of cell phones and other portable technologies that are often used behind the wheel. Experts generally agree that driver distraction stems from three sources: visual (eyes off the road), manual (hands off the wheel), and cognitive (mind off the task). Of these, cognitive distraction is the most difficult to observe and measure. While there is evidence of public and policymaker understanding of the risks involved with visual and manual distractions (especially texting while driving), there appears to be less appreciation for the risks involved with cognitive (or mental) distractions. Despite this, existing research has found evidence of the effects of this third source of distraction, suggesting that hands-free does not mean risk-free.

In addition to reviewing the literature on distracted driving, this paper introduces a landmark study by the AAA Foundation for Traffic Safety and the University of Utah of mental workload imposed on drivers by the performance of a variety of common secondary tasks: listening to the radio, listening to an audio book, conversing with a passenger, conversing on a hand-held cell phone, conversing on a hands-free cell phone, and interacting with an advanced speech-to-text system similar to those that are increasingly found in new vehicles. In addition to isolating the cognitive elements in each distracting task, this study uses advanced metrics (such as brainwave measurements, reaction time tests, and other indicators) to create a rating scale that assesses how mentally distracting each task is relative to two extremes: non-distracted driving, and driving while performing a complex math and verbal activity.

The principal finding that driver use of in-vehicle speech-to-text technologies is the most distracting of the six tasks has important implications given the skyrocketing growth in voice-activated infotainment and other dashboard systems available to consumers. The findings also challenge prevailing public assumptions that hands-free devices are safer than their hand-held counterparts.