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Research Questions Does conversing on a cell phone interfere with driving? What are the sources of the interference? Peripheral interference (dialing, holding the phone) Attentional interference (cell phone conversation) Who is affected? Are there age / expertise effects? How much are drivers affected? How significant is the interference? How do other cell phone activities compare? How do other types of conversation compare?
Citation preview
Driver Distraction: A view from the simulator
Frank Drews & David Strayer
Distracted Driving and Multi-tasking...
Research Questions
Does conversing on a cell phone interfere with driving? What are the sources of the interference?
Peripheral interference (dialing, holding the phone) Attentional interference (cell phone conversation)
Who is affected? Are there age / expertise effects?
How much are drivers affected? How significant is the interference? How do other cell phone activities compare? How do other types of conversation compare?
Simulator-Based Studies
Does conversing on a cell phone interfere with driving (Experiment 1)
Car-following paradigm Follow periodically braking pace car Required timely and appropriate reactions Hands-free cell phone (positioned in advance) Naturalistic conversations
Conditions Single vs. dual-task Low vs. moderate density *
Measures Reaction time Following distance Rear-end collisions
Low
Mod.
Single Dual
Reaction Time
800850900950
1000105011001150
Low Density Moderate Density
Reac
tion
Tim
e
SingleDual
Following Distance
2021222324252627282930
Low Density Moderate Density
Follo
win
g D
ista
nce (
Met
ers)
SingleDual
Rear-end Collisions
0
1
2
3
Low Density Moderate Density
Rea
r-end
Col
lisio
ns
SingleDual
Summary (Experiment 1)
Cell-phone driver’s Slower reaction times Drivers compensate by increasing following distance Increase in rear-end accidents
Cell-phone interference Naturalistic conversations
Why Do Cell Phones Cause Interference?
From earlier studies, no interference from: Radio broadcasts (audio input) Books on tape & recorded conversations (audio/verbal input) Simple shadowing (audio/verbal input, verbal output)
Implies active engagement in conversation necessary Impairments from both hand-held and hands-free units
Implies central / cognitive locus Inattention-blindness (Neisser, Simons)
Inattention-Blindness (Experiment 2)
Is there cell-phone induced inattention blindness?
Hands-free cell phone Naturalistic conversation with confederate Eye tracker
Two phases to the study: Phase 1: Single & dual-task driving Phase 2: Recognition memory tests for
objects encountered while driving
Recognition Memory Given Fixation
0
0.1
0.2
0.3
0.4
0.5
0.6
Single-Task Dual-Task
Cond
ition
al R
ecog
nitio
n Pr
obab
ility
Summary (Experiment 2)
Cell phone conversations create inattention blindness for traffic related events/scenes
Cell phone drivers look but fail to see up to half of the information in the driving environment
No evidence that cell phone drivers protect more traffic relevant information
Are there age / experience effects? (Experiment 3)
Car-following paradigm Follow periodically braking pace car Required timely and appropriate reactions Hands-free cell phone (positioned in advance) Naturalistic conversations
Performance Measures Reaction time Recovery time Driving speed Following distance
Younger Adults
Older Adults
Single Dual
600
700
800
900
1000
1100
1200
Younger Older
Reac
tion
Tim
e
SingleDual
Brake Reaction Time
Summary (Experiment 3)
Main effect of single vs. dual-task: Reaction time Following distance
Main effect of age: Slower reactions Slower driving speed Greater following distance
No Age x Task interaction
How Significant is the Interference?The drunk driver (Experiment 4)
Cell-phone vs. drunk-driver Redelmeier and Tibshirani (1997) suggested that “the relative risk
[of being in a traffic accident while using a cell-phone] is similar to the hazard associated with driving with a blood alcohol level at the legal limit” (p. 465).
Cell-phone Driver vs. Drunk Driver
Car-following paradigm Follow periodically braking pace car Required timely and appropriate reactions
Conditions Single-task driving Cell-phone driving * Intoxicated driving (BAC= 0.08 wt/vol)
* Hands-free = Hand-held
Reaction Time
700750800850900950
10001050
Intoxicated Driving Cell-Phone Driving
Reac
tion
Tim
e
Following Distance
25.025.526.026.527.027.528.028.529.0
Intoxicated Driving Cell-Phone Driving
Follo
win
g D
ista
nce (
met
ers)
Rear-end Collisions
0
1
2
3
4
Intoxicated Driving Cell-Phone Driving
Rear
-end
Col
lisio
ns
Summary (Experiment 4)
Compared to drunk drivers, cell-phone drivers React slower Increase following distance Compensate by increasing following distance But: Still more rear-end accidents
When controlling for time on task and driving conditions, cell-phone drivers’ performance is worse than that of the drunk driver
Other cell phone related activities: Text messaging (Experiment 5)
Car-following paradigm Follow periodically braking pace car Required timely and appropriate reactions 20 friend dyads
Conditions Single vs. dual-task
Measures Reaction time Following distance Minimum following distance Rear-end collisions
Single Dual
Reaction Time
700750800850900950
100010501100
single task dual task
Reac
tion
Tim
e
Following Distance
0.05.0
10.015.020.025.030.035.040.0
single task dual task
Follo
win
g Dist
ance
(met
ers)
mean min mean min
Rear-end Collisions
01234567
single task dual task
Rear
-end
Col
lisio
ns
Test messaging drivers Slower reaction times Increased following distance But: smaller minimum distance Increase in rear-end accidents
Things can be worse: Text messaging exceeds cell phone conversations in accident risk
Summary (Experiment 5)
Other types of conversations: Cell Phone vs. Passenger Conversations (Experiment 6)
Conditions Single task / dual task Conversing on cell phone Conversing with passenger
Design Task (2) x Condition (2)
Cell
Passenger
Single Dual
Free driving paradigm 8 miles of highway Exit highway at rest area Hands-free cell phone Close call stories / friends
Performance Measures Lane keeping Navigation task Traffic references
Cell Phone vs. Passenger Conversations
Lane Keeping Errors
0
0.2
0.4
0.6
0.8
1
1.2
Single-Task Passenger Cell Phone
RMS
Erro
r
Successful Navigation
0
20
40
60
80
100
Single-Task Passenger Cell Phone
% C
orre
ct Ex
it
Traffic References
0
1
2
3
4
Passenger Cell Phone
Num
ber o
f Ref
eren
ces
Summary (Experiment 6)
Cell-phone conversations More lane keeping errors More navigation errors Fewer references to traffic
Passenger conversations Collaborative problem solving Shared situation awareness Passenger actively supports the driver
The answers
Does conversing on a cell phone interfere with driving? Yes
What are the sources of the interference? Peripheral interference (dialing) Attentional interference (inattention blindness)
Who is affected? Younger and older drivers equally affected
How significant is the interference? Worse than listening to radio/books on tape Worse than in-vehicle conversations Worse than driving while legally intoxicated BUT: Less significant than text messaging
