Effects of In-Car Task Training on Driver Distraction by Infotainment Systems

Sammanfattning

Modern in-car infotainment systems consolidate navigation, communication, climate, and vehiclesettings into integrated touchscreens, generating concerns about driver distraction when operatorsinteract with unfamiliar interfaces while in motion. Most laboratory studies provide participantswith practice or instruction before testing, removing the unfamiliarity that poses the greatestreal-world safety risk. Whether structured pre-drive training meaningfully reduces distractionhas received almost no direct empirical attention. The present thesis addresses that questionthrough a between-subjects experiment comparing a Practiced group, who received task-specificinstruction with mastery verification before each task drive, against a Novice group, whoreceived no preparation. Sixty-four participants (32 Novice, 32 Practiced), stratified by ageacross four brackets, drove a 2023 Nissan Leaf in the Drive-In Lab, a facility that connects aproduction vehicle to a driving simulation while preserving its original infotainment system.Participants completed a car-following task while performing five infotainment tasks of varyingcomplexity. Driver distraction was operationalized as inattentiveness ratio, the proportion ofdriving time spent at unsafe headway distances during a task drive relative to each participant’sown undistracted baseline. Task throughput and System Usability Scale (SUS) ratings werecollected as secondary outcomes. Pre-drive training did not produce a statistically detectablereduction in inattentiveness ratio, a null result robust across four operationalizations of thedependent variable, a Bayesian sensitivity check, and nonparametric between-group comparisons.By contrast, training produced large improvements in task throughput across all five tasks andlarge gains in subjective usability for the most interface-intensive tasks. Task complexity exerteda stronger effect on distraction than training condition, and the dissociation between performance,usability, and attentional outcomes indicates that completion and subjective measures cannotserve as proxies for measured attentional allocation in driver safety research.