Experiment with sleepy drivers on real road

» Autoliv» Chalmers» VTI» VCC

Aim» Test of feedback and warning strategies during

the development of sleepiness based on algorithm and/or subjective ratings» How effective?» Driver acceptance?» Lasting effects?

» Evaluation of existing algorithm

Driving procedurer & participants» 12 persons (2 persons each 24 hour-

period) » Random sample from national register of

vehicle owners» Volvo S80 – double command, test leader» Road 34 from Linköping to south of Kisa» Each person drove ~140 km five times

(dose – response)» Arrive at VTI 8.00. (information, electrodes,

questionnaire, …)» Time between test drives was regulated» Finish 03.00 and 05.00 respectively» Test 15 – 30 October 2007

Driving time subject A

Driving time subject B

09.00 11.00

13.00 15.00

17.00 19.00

21.00 23.00

01.00 03.00

Drowsiness detection» Algorithm

» Lane position» Steering wheel angle» Speed» Yaw angle» Accelerometer

» References» EEG, EOG, EMG, EKG» DSS (Driver State Sensor)

» PERCLOS, Blink duration etc» Video recording

» Trigger» A recommendation was given to

the test leader from the algorithm and confirmed / send to the participant manually

Feedback and warning strategy

tIncidentDiagnos 1 Diagnos 2

(Kritiskt läge)

Index från algoritm

Δt = tillräcklig tid för åtgärd

Pigg

Sover

LDW

FCW

1

2

3

x

DROWSI – warning strategy

(1:a iden.) (2:a = D1)(D2)

1. Feedback

2. Warning 1

Arousal (”pling”)

Visual (text message)

3.Warning 2

Arousal (”pling-pling”)

Vibrations

-Steering wheel

-Seat belt

Visual (text message)

Data» Vehicle data (CAN bus + external sensors)» Physiological data (EEG/EOG/EMG + Camera (SE))» Subjective sleepiness (5 minute)

Preliminary results

» KSS» Drivers opinion about the warning strategy

and modalities» Effects on driver sleepiness and driving

behaviour

Subject 1-12

KSS

Feedback 9 participants reported experience from feedback

Did the feedback...

8

56

1

32

01 1

0

2

4

6

8

10

12

14

16

18

felt useful? (n=9) motivated you to dosomething aboutyour sleepiness?

(n=9)

influenced yourdriving performance?

(n=9)

num

ber o

f driv

ers

YesNoDon't know

6 felt more awake3 were surprised

FeedbackThe feedback, was it...

0 0

2

4

1 1

6

3

01

01

87

0 00

2

4

6

8

10

12

14

16

18

annoying? frightening? obvious why thenumber of columns

changed?

obvious what to dowhen the number of

columnsincreased?

num

ber o

f driv

ers

YesYes, fairlyNo, doubtfullyNo

Warning 1 9 participants reported experience from warning 1

Did the warning...

7

9

100 0

0

2

4

6

8

10

12

motivated you to do somethingabout your sleepiness?

influenced your drivingperformance?

num

ber o

f driv

ers

YesNo Don't know

8 felt more awake3 were surprised

Warning 24 participants reported experience from warning 2

Did the warning influence your driving?

3

11

3

0 001234

Improved your alertness(n=4)

surpriced you? (n=4)num

ber o

f driv

ers

Yes

No

Don't know

ConclusionVisual displayThe idea with feedback is experienced as positive, but it was not clear how to understand it.

Suggestion: Invert the bars

Vibrations

Effective and useful – but need to have a high amplitude

The seat belt vibrations were experienced as most annoying and most frightening.

Truck experiment - Volvo

+ sound

+ sound

+ vibrations in seat belt

Photo: Katja Kircher

Effects on driver sleepiness and driving behaviour

Participants» Feedback - 5 participants out of 9 possible to use for

sdlp, 7 for KDSmax» Warning 1 – 6 participants out of 9 possible to use» Warning 2 – not enough data

Effects in terms of–Sleepiness indicator – Karolinska Drowsiness score (KDS) & blink duration–Driving behaviour – variability in lp (sdlp)

Feedbacksdlp

0.000.050.100.150.200.250.300.350.40

Reference (min 1-5) Before (min 5-1) After (min 1-5)

Met

ers

No sign. differences within reference period, before period or after periodNo sign. Differences between before period or after period

FeedbackKDS max

0

5

10

15

20

25

Reference (min 1-5) Before (min 5-1) After (min 1-5)

Perc

ent

No sign. differences within reference period, before period or after periodNo sign. Differences between before period or after period

Warning 1sdlp

0.00

0.05

0.10

0.15

0.20

0.25

0.30

Reference (min 1-5) Before (min 5-1) After (min 1-5)

met

er

No sign. Difference between Ref. minute 5, Before minute 1 & After minute 1

No sign. differences within reference period, before period or after period

Warning 1KDSmax

048

121620242832

Reference (min 1-5) Before (min 5-1) After (min 1-5)

Perc

ent

No sign. Difference between Ref. minute 5, Before minute 1 & After minute 1

No sign. differences within reference period, before period or after period

ConclusionDriving behaviour (sdlp)

» No significant effects of feedback» No significant effects of warning 1

Sleepiness indicators (KDSmax)» No significant effects of feedback» No significant effects of warning 1

MethodMajor problems with data loss from lane tracker, artefacts in physiological

measures (EEG/EOG)High degree of ecological validityHigh degree of control of subjects Low degree of environmental control (road section, weather, traffic…)Individual differences more participants needed