Mobile Phone Use in a Driving Simulation Task: Differences
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Transcript Mobile Phone Use in a Driving Simulation Task: Differences
Mobile Phone Use in a Driving
Simulation Task: Differences in
Eye Movements
Stacy Balk, Kristin Moore,
Will Spearman, & Jay Steele
The Problem
Each year there are nearly 43,000 traffic
collisions (NHTSA, 2005)
Traffic crashes are responsible for 40
percent of deaths of people aged 15-20
(National Transportation Board, 2005)
Inattention is the most sighted cause for
traffic crashes (NHTSA, 2000)
Background
When driving, & mental workload is
increased (e.g. high traffic, visual clutter,
etc.) drivers are less able to maintain high
situation awareness.
A reduction in situation awareness may
result in a lowered ability to optimally
perform driving tasks (Gugerty 1997).
Background Cont.
In addition to normal aspects of driving,
conversing on mobile phones has been
shown to dramatically increase mental
workload (Recarte & Nunes, 2003).
This is especially troubling due to the
recent increase in the popularity of mobile
phones (Incisive Interactive Marketing,
2005)
Background Cont.
85% of all mobile phone owners talk on
their phones at least occasionally while
driving (NHTSA, 1997)
21% of crashes or near crashes reported
by respondents involved at least one
driver using a mobile phone (Seo & Torabi,
2004).
Previous Work
Strayer & Johnston (2001) found
participants who used a mobile phone
(both hand-held and hands free)
performed worse in a driving task
compared with participants who passively
listened to radio broadcasts or books on
tape.
Thus the ‘hands’ aspect is not what
degrades driving performance
Previous Work cont.
Strayer et al. found that people that talking
on mobile phones in a driving task were
more likely to experience ‘looked-butfailed-to-see’ errors (2003)
Crundall et al. (2004) found that people
talking on mobile phones have shorter
fixation durations – which may account for
‘looked-but-failed-to-see’ errors
Previous Work cont.
It has been well established that talking
while driving degrades driving
performance.
It is not known, however, which aspects of
‘good’ driving are affected when talking on
a mobile phone while driving (Gugerty,
2004)
Purpose
Engaging in TMWD increases driving errors as
well as ‘looked-but-failed-to-see’ errors, it is not
known how visual search strategies are modified
according to the specific driving task.
The current study sought to quantify if/how
visual search patterns change while engaging in
a mobile phone conversation as well as
combined with potentially hazardous driving
situations
Participants
16 (11 female) Clemson University
undergraduate students
20/20 or corrected to 20/20 vision
A valid drivers’ license
At least 2 years driving experience (M =
3.5 years).
One person was not able to participate
due to poor tracking
Apparatus
Tobii 1750 eye tracker
Sampling rate of 50 hertz
1280 x 1024 display 17 LCD screen
Design
Between subjects, 2 x 2 design.
8 people (3 male, 5 female) participated in
the mobile phone condition
8 people (2 male, x 6 female) participated
in the non-mobile phone condition.
All participants viewed 12 trials with 4
vehicles and 12 trials with 7 vehicles in the
driving scene.
Development of the Driving Simulator
C++, OpenGL, SDL
Dynamic ROI generation
Synchronization of frame rate and eye
tracker
Mirrors
Language task
Pimsleur Japanese language learning
compact disk set for beginners
3 language aspects:
Listening
Repeat
Generate
Synced to begin and end with each driving
scene
Procedure
Participants were given instructions
Practice trials
Calibration
View trials (people in the mobile phone
task ‘spoke’ simultaneously)
Answered a question about what occurred
during the scene
Confidence in their response
Procedure
After the completion of the 24 trials,
people responded to a questionnaire
about their attitudes and thoughts about
mobile phones
Results
People on the mobile phone answered
fewer questions about the scene correctly
F (1, 14) = 49.594, p < .001 (37% vs. 68%)
People in the non-mobile phone group
were more confident in their responses F
(1, 200) = 23.314, p < .001. (4.03 vs. 3.18)
Overall people answered more questions
with 4 vehicles correctly than with 7 F (1,
380) = 11.861, p = .001. (60% vs. 44%)
Results
Survey Results
All participants owned a mobile phone
On average, participants reported using their
mobile phone ‘sometimes – often’ while driving
4 participants reported using their phone nearly
every time they drove.
All felt others’ driving performance is degraded
while TMWD
However, 7 of the 16 participants felt their driving
performance was only degraded slightly or not at
all
Eye Data Analysis
Removed bad data
Velocity filter to determine fixations and
durations
ROI output from driving simulator
compared with fixations
Eye Data Results - Overall
Mobile Phone
Fewer total valid points
Percentage of fixations
of total eye points were
not different
No Mobile Phone
Larger number of total
fixations
The spread of the
fixations were not
different
Eye Data Results – ROIs over whole task
Mobile Phone
Less time spent in the
ROI
Duration of fixations
was less (supports
looked-but-failed-to see
hypothesis)
No Mobile Phone
More fixations in the
ROI
Eye Data Results – ROIs during the event
Mobile Phone
Less time spent in the
ROI
Duration of fixations
was less (supports
looked-but-failed-to see
hypothesis)
No Mobile Phone
More fixations in the
ROI
Discussion
Language task:
Controlled speed of conversation
Interest level
Etc.
Low-fidelity vs. high fidelity simulator
Eye-data ‘thinking’ phenomenon
Conclusions / future work
People may not be aware of decreased
performance when TMWD
Repeat the expt. with a more ‘involved’
task
Examine the validity
of the language task
Questions!