Designing Unambiguous Auditory Crash Warning Systems

Abstract

A series of three studies examined the acoustic characteristics that contribute to a sound being unambiguously perceived as an urgent alarm within a vehicle context. In experiment 1, participants sorted a variety of sounds modeled after sounds currently in use in driver-vehicle interfaces (DVIs) into categories indicating highly critical warnings and alerts (or "alarms"), vehicle status sounds, or in vehicle social notifications. Results indicated that four criteria (peak-to-total time ratio, interburst interval, number of harmonics, and base frequency) explained 61% of the variance in categorization. From these criteria, cutoffs were determined and manipulated to create stimuli for an initial validation study. Experiment 2 results indicated that these criteria remained robust even when examined in a larger stimulus set and with different participants. Finally, Experiment 3 investigated rapid categorization under divided attention. Participants categorized alerts while driving in a desktop driving simulator and completing a secondary distracting task. Results indicate that previously defined parameter criteria and cutoffs are applicable in higher context and under load. Furthermore, sounds that met all criteria were responded to more quickly than those which met only some or no criteria, indicating that these criteria can be used to create sounds which are unambiguous and intuitive in an in-vehicle driving context.

In-Vehicle Noise Alters the Perceived Meaning of Auditory Signals

“…Although this research observed substantial differences among auditory signals, it did not systematically manipulate acoustic parameters and features to develop specific recommended design criteria. Lewis et al (2014) provide a model for such systematic consideration of critical signal parameters. …”

“…There is opportunity for confusion when a signal is unfamiliar or is used in a manner different from the listener's past experience. Researchers have been addressing the features of auditory signals that lead to appropriate categorical perception (i.e, the sound naturally conveys the appropriate general category of meaning to a naive listener; Lewis, Eisert, Roberts, & Baldwin, 2014). Such research may provide features or parameter boundaries that result in a given signal conveying the intended general message.…”

Comparison of Traditional Psychophysical and Sorting Methods for In-Vehicle Display Design

“…Sorting methods have the advantage of lending themselves to analysis of the contribution of individual parameters to overall categorization by use of regression analyses. For example, Lewis et al (2014) found that the auditory parameters of peak to total time ratio, interburst interval, number of harmonics and base frequency explained around 61% of the variance in alarm categorization for a large set of in-vehicle information system sounds. In sum, sorting methods provide an efficient means of categorizing large numbers of stimuli and provide an effective way to examine how stimulus parameters independently and interactively impact signal perception.…”

“…Sorting is a particularly efficient method of categorizing stimuli when there are a large number of stimuli to be evaluated (Bonebright, Miner, Goldsmith, & Caudell, 2005) above and beyond more traditional paired comparison methods (Bonebright, 1996). Sorting methods can also determine which acoustic components make a sound seem like an "Alarm" or a "Social Notification" (Lewis, Eisert, Roberts, & Baldwin, 2014). The goal of the present study was to compare magnitude estimation methods of psychophysical scaling with sorting methods in order to determine the correlation between perceived urgency and signal categorization in an in-vehicle context.…”

ADAS-Assisted Driver Behaviour in Near Missing Car-Pedestrian Accidents

“…HMI can be considered as the channel through which information are conveyed to a vehicle's occupant; HMI design is one of the main issues that must be properly allowed for [5], addressing, for instance, the definition of the correct stimulus (type: visual, acoustic, haptic, etc. ; sequence; timing; priority; etc.).…”