Driver Workload Effects of Cell Phone, Music Player, and Text Messaging Tasks with the Ford SYNC Voice Interface versus Handheld Visual-Manual Interfaces

A fixed-base driving simulator study was conducted to compare driver performance and eye glance behavior effects of tasks performed using the voice interface in Ford Motor Company’s SYNC® system versus handheld operation of portable music players and cellular phones. Data were analyzed from a sample of 25 test participants. All test participants were regular SYNC users (but not SYNC developers), though they varied in their familiarity with SYNC functions. During a car-following scenario at highway speeds on the simulator, the participants performed 7 tasks using SYNC’s voice interface and those same 7 tasks with their own handheld music player and cellular phone. The seven tasks under test were: dial a 10-digit number; call a specific person from a phonebook; receive a call while driving; play a specific song; play songs from a specific artist; review (listen to or read) a text message; and select a reply from a list or type a reply to a text message. Task-level paired comparisons are reported for total eyes-off-road time, standard deviation of lane position, percentage of trials with one or more lane exceedances, speed variability, and response time to a visual detection task. Consistent with prior voice interface literature, driving distraction potential for most tasks was minimized when the SYNC voice interface was used as compared to the visual-manual interfaces of the handheld devices.