Distraction is a leading driver-related factor in fatal crashes and occurs when drivers divert their attention away from activities critical for safe driving toward a competing activity. While there is strong evidence from a large body of research indicating that tasks that take a driver’s eyes from the forward roadway significantly increase crash risk, previous research has been less conclusive about the risks of engagement in primarily cognitive secondary tasks that do not place overt visual-manual demands on the driver. This study expands on previous risk estimations of primarily cognitive secondary tasks by analyzing data from a sample of 3454 drivers whose driving was monitored using in-vehicle cameras and other sophisticated data collection equipment as part of the Second Strategic Highway Research Program Naturalistic Driving Study. The current study includes an analysis of the prevalence of drivers’ engagement in primarily cognitive secondary activities. The results indicate that, collectively, primarily cognitive secondary tasks are not associated with an increased odds ratio relative to all driving but are associated with a significantly increased odds ratio relative to model driving (i.e., drivers are apparently alert, attentive, and sober). Primarily cognitive secondary tasks were observed in 20.0% of select driving references; interacting with a passenger composed the majority of the primarily cognitive secondary tasks in which drivers engaged. Talking/listening on a hands-free cell phone did not have an increased odds ratio. (Author/publisher)
Abstract