María Alonso Human Factors Department, CIDAUT Road Safety Engineering Seminar

1. María Alonso Human Factors Department, CIDAUT Road Safety Engineering Seminar BUDAPEST (27-28th June 07) Human Factors in Road Infrastructure Design

2. Human error Everyone commits mistakes

3. Human error

4. Human error 90-95% of all road accidents have HUMAN ERROR as a component (Treat, 1977)

5. Human error • Treat (1977, et al.) performed a 5 year study that examined the causes of 2258 automobile accidents. Human error was the sole factor in 57%and a contributing factor in 92.6%. • Treat et al. further found that of accidents caused by human error, perceptual error was involved in 90% and response error in only 10%. If these results generalize to the other studies, then perceptual error is an important factor in over 80% of all automobile accidents.

6. Human error • Do not blame the driver! Not unsafe driver but unsafe system > investigate the traffic system

7. Human Factors • Performance limitations Human performance fails if conditions exceed its tolerance limits Personality Fatigue Alcohol Memory Decision making Drugs Information processing Emotion Sensation and perception Stress

8. Human Factors • Examples of degraded performance: • Diminished ability to concentrate • Increase in judgement errors • Increase in failed detection of critical events • Needless risk-taking • … • Human Factors may be defined as the technology concerned with the analysis and optimisation of the relationship between people and their activities, by the integration of human sciences and engineering in systematic applications, in consideration for cognitive aspects and socio-technical working contexts… (Cacciabue, P.C., 2004) Human Factors

9. DVE system Vehicle Environment Driver

10. influence on Road infrastructure • Road infrastructure > drivers - environment interface • information as a guide for drivers’ activity and their interactions with other road users through: • road elements • the environmental context (Saad, F., 2002) Vehicle Environment • Road • Roadside • Weather & Traffic conditions Driver • State • Personality • Task demand…

11. HCD • Human – Centred Design needed by • both engineers (knowledge of the traffic system and previous actuations) and traffic psychologists (understanding of human performance and behaviour) User Centred Design (UCD) approach, ISO 13407 preferences DRIVER expectations needs capabilities

12. SER • Self – Explaining Roads How could the infrastructure support driver’s activity? • Adoption of homogeneous and consistent design principles that take account of the different tasks to be performed by the various road users and the constraints on their execution. ‘Positive guidance’ ‘Road readability’

13. RANKERS experimental work RANKERS experiments

14. RANKERS experimental work • Experiment 1 • Road layout vs. driver performance • Experiment 2 • Road signs vs. driver perception and situation awareness 1 2 2

15. Experiment 1 • Objective: • Road layout VS. Driver performance • Analyse speed variation as a function of radius of curvature, taking into account other variables which also influence driver’s choice of speed: curve direction, roadside environment. How do drivers approach a curve? At which speeds? When do they start to react to it? Braking or releasing gas pedal? How do they behave along the curve? Curve negotiation

16. Experiment 1 • Scenario • AP-66 motorway (León - Campomanes) PICTURES

17. Experiment 1 • Experimental vehicle

18. Experiment 1 • In-depth exploration, expert analysis • Experts drive session for road inspection

19. Experiment 1 • Field Studies: experimental design - Variables -

20. Experiment 1 • Field tests Video – test example

21. Experiment 2 • Objective: • Analyse road sign features (design, content, amount) in terms of their adaptation to road environment, traffic situation and driver needs. Can drivers perceive certain road signs? Can they interpret them? Is the number of signs appropriate? Are them visible?

22. Experiment 2 • Scenario • AP-15 motorway (Tudela - Irurtzun)

23. Experiment 2 • First exploratory phase • Experts drive session for road inspection • Video recording

24. Experiment 2 • In-depth exploration, expert analysis • Analysis of encountered problems

25. Experiment 2 • Users Tests • Subjective analysis of significant aspects of traffic signs • 20 subjects: • Gender: Male & Female • Age: > 25 years • Experience: > 10.000 km driven • Tools: • Driving profile questionnaire • Traffic signs questionnaire

26. General aspects: Indication Shape Colour Reinforced message Highlighted features Obstacles Is this sign necessary? Could this sign cause distraction? Appropriate frequency Assessment of traffic features: Location Size & shape Colour vs. Environment Text Symbols and Icons Typography Amount of information Contrast Distribution of contents Experiment 2 • Traffic signs questionnaire Global assessment: 1-5

27. Results Recommendations + Best practices • Experiment 1 Road layout vs. driver performance • Experiment 2 Road signs vs. driver perception & situation awareness RANKING OF RECOMMENDATIONS RSI eBook

28. What to avoid?

29. What to encourage?

30. Thanks for your attention! Human Factors in Road Infrastructure Design