Title page for ETD etd-08032004-141805

Type of Document Master's Thesis
Author Fitch, Gregory Malcolm John
Author's Email Address gfitch@vt.edu
URN etd-08032004-141805
Title Drivers' Ability to Localize Auditory and Haptic Alarms in Terms of Speed and Accuracy
Degree Master of Science
Department Industrial and Systems Engineering
Advisory Committee
Advisor Name Title
Kleiner, Brian M. Committee Chair
Babski-Reeves, Kari L. Committee Member
Kiefer, Raymond J. Committee Member
Lee, Suzanne E. Committee Member
  • Sound Localization
  • Auditory Alarm
  • Spatial Audio Display
  • Haptic Display
Date of Defense 2004-06-29
Availability unrestricted
This study investigated automobile drivers' ability to localize auditory and haptic (touch)

alarms in terms of speed and accuracy. Thirty-two subjects, balanced across age (20-30 years

old and 60-70 years old) and gender, participated in the study. Subjects were screened for

minimum hearing of 40 dB for 500 Hz through 4000 Hz auditory tones, and maximum

bilateral hearing differences of 10 dB. The experiment consisted of subjects identifying the

target location of an alarm while driving a 2001 Buick LeSabre at 55 mph in light traffic.

Four alarm modes were tested: 1) an auditory broadband alarm, 2) a haptic seat, 3) a

combination of the haptic and the auditory alarm modes, and 4) a combination of the haptic

alarm mode with a non-directional auditory alarm played from the front speakers of the

vehicle. The alarms were evoked from eight target locations: the front-left, front, frontright,

right, back-right, back, back-left, and left. The target locations of the auditory alarm

mode existed around the interior of the car cabin using the vehicle's stock sound system

speakers. The haptic alarm target locations existed in the bottom of the driver seat using an

eight-by-eight grid of actuators. The experimenter evoked the alarms while subjects drove

along a two-lane highway, and the alarms were not associated with any actual collision threat.

Subjects were instructed to quickly identify the location of the alarm by calling them out,

while being as correct as possible. Their choice response time and target location selection

was recorded. The alarms were presented approximately every minute during fifteen-minute

intervals over the duration of two and a half hours. Subjects completed questionnaires

regarding their preference to the alarm modes. Under the conditions investigated, subjects

localized the haptic alarm mode faster and more accurately than the auditory alarm mode.

Subjects performed equally well with the haptic alarm mode and the two auditory and haptic

combination alarm modes in terms of speed and accuracy in identifying their location.

Subjects did express a preference for the addition of the auditory component to the haptic

alarm mode, perhaps owing to a heightened sense of urgency. However, subjects preferred

the haptic alarm mode on its own in response to hypothetical false alarm questions, perhaps

because it was less annoying. Alarm mode discriminability was believed to affect localization

accuracy and response time owing to its effect on the likelihood of correctly identifying a

target location and the attention resources required to differentiate adjacent target locations.

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