A summary of five years of work looking at testing psychological models that seek to explain why people drive the way that they do. This presentation was originally given at VTI in Sweden, Feb, 2012.

1. Testing models of
Driver Behaviour
Ben Lewis-Evans
b.lewis.evans@rug.nl

2. Why? Do people drive like this?

3. Why? Do people drive like this?

4. The Answer?
MODELS!

5. Some have been tested

6. Utility
Models
Trading off risks and
safety to get the
optimal benefit

7. Utility
Models
―… people… run
risks, but they do
not take them‖
Wagenaar (1992)

8. Attitude
Models
Attitude
Intention
Behaviour

9. Attitude
Models
―…accidents are
not caused by risky
attitudes but by
risky behaviour‖
Rothengatter et al (1989)

10. But most have not

11. So?
Time for SCIENCE!

12. Experiment One
Behavioural Adaptation
to Road Width
Lewis-Evans & Charlton (2006)

13. METHOD
DS9 Driving Simulator
49 participants (25 M 24 F)
All full licence holders
23.8 years old on average
Speed, ratings, & open questions

14. METHOD
Four Roads
Practice
Narrow(W) Control (E)
- 2m
Wide (S)
+ 3m

15. Narrow(W)
Wide (S)
Control (E)

16. RESULTS Speed
*
*
*
*
* statistically significant difference (at least p < .05)

17. RESULTS Ratings
* *
*
*
statistically significant difference (at least p < .05)

18. RESULTS What was different?
―Road Width‖ 10 people , only 1
correct
―Nothing‖ 8 people
Narrow road had more ―Curves‖ 14
people
Many non-factual responses e.g.
narrow road had more trucks

19. CONCLUSIONS Experiment 1
Impact of (narrow) road width
on speed
Associated with increases
in risk and task difficulty
Awareness of road width
changes low

20. Experiment Two
Speed and the assessment
of risk, difficulty, effort and
comfort
Lewis-Evans & Rothengatter (2009)

21. Fuller, McHugh
& Pender (2008)
Digitally altered video
Increasing 5 mph increments
3 road types
Task difficulty and Risk
(feeling & probability)

22. Fuller, et al (2008)
Residential

23. ―…task difficulty
and feelings of risk
are continuously
present variables
which inform driver
decisions…‖
Fuller, et al 2008

24. METHOD
47 participants (25 M 22 F)
~20-21 years old
Two roads: urban & rural
Observation & Driving
9 randomly presented speeds
(10 km/h increments + Free choice)

25. METHOD
Speed data + Subjective ratings
Task difficulty
Feeling of Risk
Crash risk
Habit/Typicality
Effort
Comfort

26. RESULTS Averaged Driving
Residential – Fuller et al Residential – Lewis-Evans &
(2008) Rothengatter (2009)

27. RESULTS Averaged Driving
Residential

28. RESULTS Relative to free speed
choice
Residential

29. CONCLUSIONS Experiment 2
Fuller et al (2008) not replicated
Threshold or U-shaped trends
Task difficulty, feeling of risk, &
effort highly correlated
Habit appears to be important

30. Experiment Three
Close following -
risk, difficulty, effort
and comfort
Lewis-Evans, de Waard, &
Brookhuis (2010)

31. Subjective impressions;
Constant or Threshold?

32. METHOD
METHOD
40 participants (20 M 20 F)
17 Inexperienced, 23 Experienced
Residential road, left & right side
9 randomly presented 50 km/h
following distances
(0.5 to 4.0 sec + Free
choice)

33. METHOD
Distance + Subjective ratings
Task difficulty
Feeling of Risk
Crash risk
Typicality
Effort
Comfort

34. RESULTS Averaged

35. RESULTS Relative to free choice

36. CONCLUSIONS Experiment 3
Threshold trends again
Task difficulty, feeling of risk, &
effort highly correlated
Habit appears to be important
No impact of Experience
or side of road

37. Experiment Four
Speed maintenance
under cognitive
load
Lewis-Evans, de Waard, &
Brookhuis (2011)

38. Question
What is the impact
of secondary
mental workload
on these trends?

39. METHOD
Four conditions (1 min)
Baseline sets speed
Baseline +/- 0 to 30 km/h
Counter balanced
Baseline +/- 0 to 30 km/h
+ PASAT
Return to Baseline

40. Paced auditory serial
PASAT addition task
6 5 4
4 2 3 1 …

41. METHOD
53 participants (21 M 32 F)
Speed data + Subjective ratings
Task difficulty
Feeling of Risk
Typicality
Effort
Comfort

42. RESULTS Ratings
Baseline vs Return to baseline

43. RESULTS Ratings
Baseline vs Experimental
* *
* *
* * *
* *
*
* * * *
* * *
*
statistically significant difference (at least p < .05)

44. RESULTS Ratings
Experimental vs PASAT
* * * * * * *
* * * * * * *
* *
* * *
* *
*
statistically significant difference (at least p < .05)

45. RESULTS Speed
Baseline vs Return to baseline
* * * * * *
*
statistically significant difference (at least p < .05)

46. RESULTS Speed
Experimental vs PASAT
*
*
*
*
statistically significant difference (at least p < .05)

47. CONCLUSIONS Experiment 4
Threshold trends still apparent
Mental workload shifts them
Speed control habitual
Unintentional Speeding

48. Experiment Five
Unfelt emotions and
speed
Lewis-Evans, de
Waard, Jolij & Brookhuis
(2012)

49. Emotions are important
Behaviour is maladaptive
without them

50. i.e. Vulcans are wrong

51. Unfelt Emotions?
Emotions: physiological reaction
Feelings: conscious awareness

52. Much of
Driving is automatic
So can unfelt emotions affect it?

53. How to test?
Ethics committees take a dim
view of the above

54. Did you notice anything?

55. Godzilla
Did you notice anything?

56. METHOD
Masked Images
800 ms 32 ms 800 ms
Deception: Images part of a
―memory task‖

57. METHOD
113 initial participants (39 M 74 F)
- 8 saw (6 M 2 F)
- 19 ―suspicious‖ (7 M 12 F)
= 85 participants (26 M 59 F)
Speed, subjective, bio

58. METHOD Images
Masks Arousal 2.76 Valence 4.97
800 ms
Neutral Arousal 2.78 Valence 4.86
32 ms
Negative Arousal 6.59 Valence 1.80
32 ms

59. High Arousal
Scared
Negative Excited
Low High
Valence Valence
Neutral
Masks
Bored Relaxed
Low Arousal

60. RESULTS Speed

61. RESULTS Physiological
Task effect HR HRV
Order x Image effect
Neg to Neu HR HRV
Neu to Neg HR HRV

62. RESULTS Subjective &
Memory task
No consistent effects on ratings
of risk or effort
Good performance on the
―memory task‖

63. CONCLUSIONS Experiment 5
Images supressed time on task effects
Unconscious influences on driving
No support for any specific model
Gender?

64. In Conclusion
People may run
risks, but they do
not usually feel
them
But what they do
not feel may still
affect them

65. The Moon
Thank You
Questions?
b.lewis.evans@rug.nl

66. References
Fuller, R., Bates, H., Gormley, M., Hannigan, B., Stradling, S., Broughton, P., Kinnear, N., & O’Dolan, C. (2008). The
Conditions for Inappropriate High Speed: A Review of the Research Literature from 1995 to 2006.
London: Department for Transport.
Fuller, R., McHugh, C., & Pender, S. (2008). Task difficulty and risk in the determination of driver behaviour. Revue
Européenne De Psychologie Appliquée/European Review of Applied Psychology, 58(1), 13-21.
Lewis-Evans, B., & Charlton, S. G. (2006). Explicit and implicit processes in behavioural adaptation to road width.
Accident Analysis & Prevention, 38(3), 610-617.
Lewis-Evans, B., & Rothengatter, T. (2009). Task difficulty, risk, effort and comfort in a simulated driving task—
Implications for Risk Allostasis Theory. Accident Analysis & Prevention, 41(5), 1053-1063.
Lewis-Evans, B., de Waard, D., & Brookhuis, K. A. (2010). That's close enough—A threshold effect of time headway on the
experience of risk, task difficulty, effort, and comfort. Accident Analysis & Prevention, 42(6), 1926-1933.
Lewis-Evans, B., de Waard, D., & Brookhuis, K. A. (2011). Speed maintenance under cognitive load –
Implications for theories of driver behaviour. Accident Analysis & Prevention, 43(4), 1497-1507.
Lewis-Evans, B., de Waard, D., Jolij, J., & Brookhuis, K. A. (2012). What You May Not See Might Slow You Down
: Masked Images and Driving. PloS One, 7(1), e29857.
Rothengatter, J. A., De Bruin, R. A., & Rooijers, A. J. (1989). The effects of publicity campaigns and police
surveillance on the attitude-behaviour relationship in different groups of road users. Proceedings
of the Second European Workshop on Recent Developments in Road Safety Research, France. 197-
202.
Wagenaar, W. A. (1992). Risk taking and accident causation. In J. F. Yates (Ed.), Risk-Taking Behaviour . , Englewood
Cliffs, NJ: John Wiley & Sons.

67. All images belong to
their respective
copyright holders