In 2002 there were 590 fatal traffic accidents in Minnesota, and an estimated 17%
of these occurred at rural thru-stop intersections. A thru-stop intersection presents a
challenge to a driver attempting to cross or enter the highway because he must stop at the
stop sign and wait for a gap in highway traffic. If a driver misjudges whether a gap is
large enough, a high-speed collision with highway traffic may result.
Previous studies have developed a prototype decision support sign (often referred
to as the Icon Sign) that is aware of highway traffic and warns drivers when it is not safe
to cross. The current study conducted a driving simulator experiment to test two invehicle
decision support systems and compare them to the Icon Sign. The first in-vehicle
system, called the Side Mirror Displays, consisted of two visual displays located on the
vehicle’s side mirrors. The second system, called the Vibrotactile Seat, was a driver’s
seat with left and right vibrational pads.
No system clearly outperformed the others in terms of promoting safer driving
behavior, nor did any improve driving performance compared to the control condition.
The questionnaire and usability data showed that the Icon Sign was most preferred, with
50% of participants rating it as their top choice. The Icon Sign may have been preferred
because drivers are more accustomed to gaining information from traffic signs and
signals than from other systems. The Side Mirror Displays and Vibrotactile Seat were
preferred nearly equally, with each rated as top choice by 25% of participants. The Side
Mirror Displays were comprehended by 83.3% of participants, the Icon Sign by 62.5%,
and the Vibrotactile Seat by 58.3%. The high comprehension rate for the Side Mirror
Displays may have been due to the display continuously changing, giving the driver more
opportunities to interpret the displays and deduce what information the displays were
In future work, the Side Mirror Displays should incorporate advisory messages, telling the driver when to wait instead of merely indicating the distance to approaching
traffic. This could aid interpretation of the Side Mirror Displays. For the Vibrotactile Seat, the vibrational pads should be spaced farther apart so that drivers can better
distinguish the left and right vibrations instead of mistaking them for a single vibration.
Results so far indicate that a visual display would be easier to comprehend than a
vibrotactile display when no training or explanation is provided. No results of this study
indicate that in-vehicle systems are an inherently poor means of presenting traffic gap
information to the driver.
University of Minnesota M.S. thesis. October 2010. Major: Mechanical Engineering. Advisor: Caroline C. Hayes. 1 comnputer file (PDF);viii, 169 pages, appendices A-W. Ill. (some col.)
Drew, Daniel Allen.
In-vehicle decision support systems for collision avoidance at rural thru-stop intersections..
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