Abstract
An on-road field study was conducted to assess how attention demand changes as a function of auditory display characteristics. Two auditory message set characteristics were manipulated: speech rate (“normal” 125 wpm vs. “time-compressed” 225 wpm), and auditory format in which information was presented in either prose form where the content is embedded within declarative sentences (e.g., the Ramada has a vacancy and is 48 miles away), or in lists (Ramada, vacancy, 48 miles). Twenty-four subjects completed a two-hour drive using an instrumented vehicle in which they experienced auditory and visual displays on both freeway and parkways. Subjects used the information presented to them to complete a range of tasks such as selecting the quickest route to a destination, or navigating to avoid congestion. Primary measures included: minimum headway, speed variance, maximum steering wheel velocity, steering wheel variance, lane deviation, peak lateral acceleration, and subjective workload ratings. Auditory format and speech rate significantly affected vehicle steering (steering variability), speed (average, minimum, and variance), and headway (variance). Evidence suggests that accelerated speech displays (225 wpm) can be used without sacrificing driver comprehension or driving performance, and that auditory content communicated in list-type formats is equal to or better than full length prose messages in terms of driver performance and information processing.
Get full access to this article
View all access options for this article.