maría alonso human factors department, cidaut road safety engineering seminar

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sustainable surface transportsixthframework programme

María AlonsoHuman Factors Department, CIDAUT

Road Safety Engineering SeminarBUDAPEST (27-28th June 07)

Human Factors in Road Infrastructure Design

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2http://[email protected]

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Road Safety Engineering SeminarBUDAPEST, 28 / 06 / 07

Human error

Everyone commits mistakes

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Human error

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Human error

90-95% of all road accidents have HUMAN ERROR as a component

(Treat, 1977)

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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.

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Human error

Do not blame the driver! Not unsafe driver but unsafe system> investigate the traffic system

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Human Factors

Performance limitations

Human performance fails if conditions exceed its tolerance limits

Sensation and perceptionInformation processing

Memory

Decision making

FatigueAlcohol

Drugs

Emotion

Stress

Per

sona

lity

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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

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DVE system

Vehicle Environment

Driver

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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…

influence on

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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

needs

preferences

expectations

DRIVER

capabilities

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SER

Self – Explaining RoadsHow 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’

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RANKERS experimental work

RANKERS experiments

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Experiment 1 Road layout vs. driver performance

Experiment 2 Road signs vs. driver perception and

situation awareness

RANKERS experimental work

1 2

2

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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

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Experiment 1

Scenario AP-66 motorway (León - Campomanes)

PICTURES

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Experiment 1

Experimental vehicle

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Experiment 1

In-depth exploration, expert analysis Experts drive session for road inspection

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Experiment 1

Field Studies: experimental design- Variables -

Independent variable

IV

Dependent variable

DVControl variables and co-variables

Radius of curvature

Large

Driver performance

measures

- Speed- Gas/Brake

pedals- Lateral

acceleration- Longitudinal acceleration- SWA

GenderMale

Small Female

Road familiarityYes

No

Driving Experience

≤ 5000 km/year

≥ 5000 km/year

Curve directionLeft-hand

Right-hand

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Experiment 1

Field tests

Video –

test example

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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?

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Experiment 2

Scenario AP-15 motorway (Tudela - Irurtzun)

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Experiment 2

First exploratory phase Experts drive session for road inspection Video recording

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Experiment 2

In-depth exploration, expert analysis Analysis of encountered problems

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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

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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

Traffic signs questionnaire

Global assessment: 1-5

Experiment 2

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Experiment 1

Road layout vs. driver performance

Experiment 2

Road signs vs. driver perception & situation awareness

Results

Recommendations

+

Best practices

RANKING OF RECOMMENDATIONS

RSI

eBook

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What to avoid?

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What to encourage?

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Thanks for your attention!

Human Factors in Road Infrastructure Design

maría alonso human factors department, cidaut road safety engineering seminar

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