urban road safety how to deal with complexity? d. fleury – inrets conference physics and the city
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Urban Road Safety How to deal with complexity? D. Fleury – INRETS Conference Physics and the City. Bologna 15-17 December 2005. Department of Accident Mechanisms (INRETS) Research in the field of Road Safety - PowerPoint PPT PresentationTRANSCRIPT
Urban Road Safety
How to deal with complexity?
D. Fleury – INRETS
Conference Physics and the City.
Bologna 15-17 December 2005
Department of Accident Mechanisms (INRETS)
Research in the field of Road Safety A multidisciplinary team (cognitive psychology,
ergonomics, civil engineering, town planning, law, political science, vehicle engineering)
The “system” 'approach as a theoretical framework
Interdisciplinary modelling
In Depth Accident Investigation (IDAI)Études détaillées d’accidents (EDA)
Complexity in the traffic system
The result of situational heterogeneity and multiple retroactions
The most common modelling of the road traffic system: [man]-[vehicle]-[road environment]
Specific research issues based on system analysis
Micro-regulation of the traffic system
Man (driver-pedestrian) regulates the (M/V/R) system in real time
Macro-regulation and social management of safety
Regulation performed in “response” delay time, with the observation of user behaviour (driving speeds, accidents, perceived risks, opinions, etc.)
Accidents are the symptom of a dysfunctional situation in the interactions between components in the M/V/R system
Information input and processing
Action on control units
Man Vehicle
Road environment
Dynamic behavior of the vehicle
Simplified functional model for the analysis of safety (INRETS)
Informationinput
Processing Choice and decision-making
Action Conse-
quences
Example of a functional model (MDAI project)
Phased models
Baker and Fricke (1986)
Phase analysis and space analysis
General conditions
Driving situation
Accident situation
Emergency and collision situations
network and choice of itineraries
characteristics of the carriageway and section
break related to a section or particular location
(intersection, for example)
fine characteristics of the
location
Consistency (between the different levels) of the layout in question
Improve the overall consistency of the entire (socio-technical) traffic system to improve safety.
Parallel between individual user control and actions on space.
Accident analysis, not restricted to immediate interaction, leading to actions for treating black spots as well as town planning and transportation policy.
A field of research: the notion of typical scenarios as “road pathologies"
Example
Wide through road, problems of visibility (night, wetness, age, advertising, etc.)
Driving situation
High speed, low attention
Pedestrian preparing to cross outside a pedestrian crossing
Accident situation
View obstructed by a standing vehicle, the pedestrian crosses
Emergency situation
No manoeuvre (surprise)
Collision situation
Pedestrian hit
Example of research on accident scenarios : from IDAI (EDA) to intelligent safety diagnosis
1. Construction of “scenarios” on a panel of accidents
2. Scenarios recognition through police reports (and accident files)
Structure of the knowledge field
Symptoms (data) for recognition
Statistical inferences
3. Links between road environment and accident scenarios
Road types
Scenarios profiles (% of each scenario)
Modelling Micro-regulation
Systems with decision-making and memory centres (ref.: Boulding)
TASK AND ITS CONSTRAINTS
Ambience: road & traffic MAN
VEHICLE ACTIVITY
memorization
decision
Models coming from psychology and safety diagnosis of large socio-technical systems
On the role of memorisation.
Rasmussen model (1980), level of cognitive operation: problem, procedural and automation resolution.
On decision-making and motivation.
Risk models: risk homeostasis (Wilde, 1988), zero risk (Näätänen and Summala, 1974), threat avoidance (Fuller, 1984).
Macro-regulation and social management of safety
Environment: road & traffic
MAN
VEHICLE
TASK AND ITS CONSTRAINTS ACTIVITY
memorization
decision
TECHNICAL MANAGEMENT
To improve safety, we have to understand the Functional descriptions of the system and the regulation goals
Understanding how the system operates (functions)
Understanding the process of action
Analysing the implicit models on which this action is based
Research example:
Urban Travel Plan design (Plans de Déplacements Urbains)
Obligations in:
Law on the Air and Rational Energy Use – 1996
Law on Solidarity and Urban Renewal – 2000
Follow-up work meetings for nearly one and a half years
Design Process
1
Processus de conception
The “Relatiogram” – Frédérique Hernandez
2
Le « relatiogramme » - Frédérique Hernandez
The Urban Travel Plan as a scene for actors
Construction of a “reference project” by clustering "operational projects":
technical objects (tramway…) technical layout concepts (traffic calming…)
4
Marseille Urban Travel Plan (Hernandez, 2000)
Three main scenarios:
“town centre” scenario grouping together projects such as "pedestrian priority hypercentre", "tramway" and "cycling",
“periphery” scenario with secondary centres, 30 km areas, Southern Urban Boulevard, etc.
“cluster” scenario with the “regional express rail network” and the “Blancarde Aubagne route"
Referring to an "island strategy" concerning automobile traffic
6
Some conclusions:
Safety research entails modelling
Different levels of representations of unsafe situations
Both aspects: techniques and decision making
How to make explicit the models of action
Stressing the “unspokens” of planning (importance of Ring roads, forgetting mopeds and motocycles, etc.)
The possible consequences on safety (accident scenarios)