Experience of Cognitive Workload During In-Vehicle Distractions

Abstract

AbstractDrivers’ ability to capture driving related information, interpretation and timely action upon that information determines safe driving. However, the cognitive resources of the driver to perceive, interpret, and execute driving related information are limited. The limitation of cognitive resources brings the issue of cognitive workload in focus. In the light of this understanding, the current study examines in-vehicle object and spatial distractions in terms of their effect on cognitive workload experienced by drivers. 47 drivers voluntarily participated in this test-track study. Equal number of drivers were randomly assigned to in-vehicle object and spatial distraction conditions. Drivers assigned to object distraction condition had to process object appearance information whereas under spatial distraction they had to process spatial information. After the completion of the drive, each driver’s cognitive workload was assessed by using National Aeronautics and Space Administration-Task Load Index (NASA-TLX). It was observed that there is a significant difference between in-vehicle object and spatial distraction with respect to their effect on cognitive workload. The results indicate that the drivers experienced more cognitive workload during object distraction. Multiple regression analysis of cognitive workload reveals that temporal demand, effort, and performance dimensions are significant predictors of overall cognitive workload, but the other three dimensions (i.e., mental demand, physical demand and frustration level) are not. Further, the stepwise analysis of the dimensions of NASA-TLX showed that temporal demand is the most dominant factor which contributed to 85% of the cognitive workload experienced by the drivers.KeywordsIn-vehicle distractionsCognitive workloadDistracted drivingWorking memory