Thirty Years of Traffic Safety Research

Transcription

1 20th ICTCT WS in Valencia 25./ Thirty Years of Traffic Safety Research Herbert Gstalter & Wolfgang Fastenmeier 1

2 From accidents to conflicts: Work with the Traffic Conflicts Technique (TCT) Technical University of Braunschweig Heiner Erke, Bernhard Zimolong, Herbert Gstalter Development of a national TCT Funded by the German Federal Highway Administration (BASt) International Cooperation in ICTCT 2

3 International Cooperation in ICTCT ICTCT= International Cooperation on Traffic Conflicts Techniques First workshop on traffic conflicts in Oslo 1977 Calibration studies in Rouen 1979, Malmö

4 Development of a national TCT Definition of conflict types, degrees of severity Methodological and statistical issues Validation of conflicts with respect to accidents Training procedures Handbook of TCT (Erke & Gstalter 1985) 4

5 From conflicts to errors: Technical University of Munich Carl Graf Hoyos, Wolfgang Fastenmeier Lessons from occupational safety work The importance of the concept task Safety is more than the absence of accidents 5

6 From conflicts to errors Development of error counting methods in traffic Human reliability assessment (HEP) Applications in different contexts, e.g. - Comparing groups of drivers - Individual assessment of driving ability - Evaluation of ADAS - Finding driver information needs - Stress and strain in driving 6

7 International activities Second Workshop of ICTCT in Munich 1989: Theoretical aspects and examples for the practical use of traffic conflicts and other interactional safety criteria ICTCT had become International Cooperation on Theories and Concepts in Traffic Safety 7

8 Some differences between... Conflict Techniques Error research Diagnosis of Traffic sites (safety diagnosis, before-after studies) Quality of the interaction between driver, car and environment Personal diagnostics Effects of electronic in-car devices Method On-site observation by human observer Technical recordings of observable events In-car observation technical recordings Data used Conflicts, violations, traffic volume Errors and exposure data Vehicle dynamics Physiological measures Subjective driver ratings Secondary tasks Video recording & video confrontation Evaluation criteria Safety and efficacy of traffic flow Safety as reliability estimate Comfort Acceptance 8

9 From errors to normal driving: Driving task analysis Diagnose & Transfer mensch-verkehr-umwelt since 2001 Errors as deviations from correct behaviour in defined driving situations Taxonomy of driving tasks Procedure for analysis and assessment of driving tasks (SAFE) 9

10 Accidents The Safety Continuum Conflicts Errors and violations Correct Behaviour Risk Frequency 10

11 Shifting the focus on the safety continuum: Development or progress? A multitude of methods became available and is used and accepted Better understanding of the accident process (reasons, not only causes) Better understanding of the mental requirements of different driving tasks Recovery from errors not leading to accidents can be studied 11

12 Advantages of error counting in traffic (compared to accident data) Errors occur in larger numbers and allow a good estimate of statistical values The sampling is more complete and its reliability can be measured The counting procedures can be trained and are more objective Questions of guilt do not distort the data Errors (and conflicts) can economically be registered at all traffic sites, accident black spots mainly occur at sites with high traffic volumes Errors can be observed live and the process can be documented, e.g. by films All situational variables that may affect the accident event can be registered in real time The success of countermeasures can quickly be assessed after the treatment The general quality of the traffic process (apart from safety issues) can be assessed The recovery from errors not leading to crashes can be studied 12

13 Problems of Accident Research Rare events with low reliability and predictive value Not all accidents are reported Accident protocols are distorted by questions of guilt and by subjective concepts of accident causation ( human failure ) Accident black spots usually only occur in sites with heavy traffic volume; black spot orientation for countermeasures is distorted by regression to the mean phenomenon The course of events leading to an accident can only be reconstructed in a retroanalytic fashion Problems with the accuracy of informations by accident witnesses Accident data is not available for new traffic sites Before-after studies in safety evaluation take their time 13

14 Traffic Conflicts Definition by Oslo Conference, 1977: A traffic conflict is an observable situation in which to or more road users approach each other in space and time to such an extent that there is a risk of collision if their movements remain unchanged. Traffic Conflict Techniques (TCT) use subjective and/or objective data to indicate risk. Subjective methods operationalise the risk by evasive actions of road users (breaking or swerving). Objective measures use time-space criteria, e.g. the Swedish approach uses time to collision (< 1.5 sec defines a conflict). But also this technique uses human observers on the road. Rare events with low reliability and predictive value Most techniques differentiate between slight or serious conflicts (near accidents). Most investigations found positive correlations between accidents and conflicts on traffic sites. TCT s are mostly used for safety diagnosis of traffic sites or in the evaluation of safety measures in before-after studies. One approach (Vienna driving test) was constructed to count conflicts of a driver on a fixed route instead of on-site observation. 14

15 Effekte von ACC Accident Causation Interaction model of the traffic system Exposure correct behaviour 1 - HEP Reliable state of system Erroneous behaviour HEP Automatic Error compensation by the system successful coping successful emergency manoevreus System disturbance 1 Hazard avoidance 2 Hazard reduction Necessity of compensatory manouvreus Conflict unsuccessful coping 3 Hazard 4 Hazard accomplishment accomplishment Nearaccident unsuccessful omitted emergency action Accident 5 Hazard accomplishment 15

16 Psychological varieties of unsafe acts Basic error types Slip Attentional failures Unsafe Acts Unintended Action Intended Action Lapse Mistake Violation Memory failures Rule-based mistakes Knowledge-based mistakes Routine, exceptional, sabotage violations 16

17 Example Observation Sheet Fehlerliste / Segmente Geschwindigkeit zu schnell 2 Geschwindigkeit zögernd/schwankend 3 unangepaßte Beschleunigung 4 unangepaßte Verzögerung 5 Längsabstand zu gering (Drängeln) 6 zu knappe Lücke (Reinquetschen) 7 Seitenabstand rechts zu gering 8 Seitenabstand links zu gering 9 blinkt nicht 10 blinkt zu spät 11 Spurungenauigkeit bei Spurwechsel 12 Spurungenauigkeit im Aufstellbereich 13 Spurungenauigkeit beim Abbiegen 14 falsche Spurwahl 15 Einordnung zu spät 16 Einordnung falsch 17 Einordnung zu zögernd 18 Verlangsamung zu spät 19 fährt bei Gelb 20 fährt bei Rot 21 fährt nicht trotz Grün 22 fährt in volle Kreuzung 23 stures Hinterherfahren 24 nutzt den Aufstellraum nicht 25 räumt Kreuzung zu zögernd 26 fährt zu weit in Querverkehr rein 27 unflexibel bei Hindernis/Spurvereng etc 28 andere Zeichenfehler 29 Sichert zu wenig nach links 30 Sichert zu wenig nach rechts 31 Sichert zu wenig nach hinten 32 fährt zu weit in FG/RF Furt rein 33 behindert FG 34 behindert RF 35 zu geringe Aufmerksamkeit (vgl. Blick) 36 Beharren auf Vorrang VP-Num m e r Me ßp unkt Situationstyp: C4K4 links T-Kreuzung S4 S3 S2 S1 Radweg 17