International Calibration Study of Traffic Conflict Techniques NATO ASI Series Advanced Seien ce Institutes Series Aseries presenting the results of activities sponsored by the NATO Science Commiffee, which aims at the dissemination of advanced scientific and technological knowledge, with a view to strengthening links between scientific communities. The Se ries is published by an international board 01 publishers in conjunction with the NATO Scientilic Affairs Division A Life Seien ces Plenurn Publishing Corporation B Physics London and New York C Mathematical and D. Reidel Publishing Company Physical Seien ces Dordrecht Boston and Lancaster D Behavioural and Martinus Nijhoff Publishers So ci al Sciences Boston, The Hague, Dordrecht and Lancaster E Applied Sciences F Computer and Springer-Verlag Systems Sciences Berlin Heidelberg New York Tokyo G Ecological Sciences Series F: Computer and Systems Sciences Vol. 5 International Calibration Study of Traffic Conflict Techniques Edited by Erik Asmussen Institute for Road Safety Research SWOV, The Netherlands Springer-Verlag Berlin Heidelberg New York Tokyo 1984 Published in cooperation with NATO Scientific Affairs Division Proceedings 01 the NATO Advanced Research Workshop on International Calibration Study 01 Traffie Conflict Techniques held at Copenhagen, May 25-27, 1983 ICTCT Organizing Committee E. Asmussen, U. Engel, C. Hyden, E. Imre, J Kraay, N. Muhlrad, S. Oppe ISBN-13 • 978-3-642-82111-0 e-ISBN-13.978-3-642-82109-7 DO I 10.1007/978-3-642-82109-7 Library of Congress Cataloglng in Pubiication Dats. NATO Advanced Research Workshop on International Cailbratlon Study ofTraffic ConflictT echniques (1983. Copenhagen. DenlTark) International ealibration study of traffie eonfliet teehniques. (NATO ASi series. Serles F. Computer and systelTs sciences; no. 5) "Proceedings of the NATO Advaneed Research Workshop on International Calibration StudyofTraffic ConfilctTechniques held at Copenhagen, May 25-27,1983"-Tp. verso. "Pubilshed In cooperation with NATO Scientlflc Affalrs Dlvision"-Tp. verso. ,. Traftic confilcts-Research-Congresses. 2. Traffic accidents-Research-Congresses. 3. Traffic safety Research-Congresses. I. Asmussen, E. (Erik), 1924. 11. North Atlantic Treaty Organizatlon. Scientlfic Affairs DiVision. 111. Title. IV. Series. HE5614N392 1983363.1'256383-20336 ISBN 0-387-12716-X (US) This work is subject to copyright All rights are reserved, whether the whole or part oi the rnaterial is concerned, specifically those of translating, reprinting, re-use of illustrations, broadcastings. reproduction by photocopying machine or similar rneans, and storage in data banks. Under § 54 oi the German COPYright Law where coples are made for other than prrvate use, a fee is payable to "Verwertungsgesellschaft Wort", Ivlunich. © Springer-Verlag Berlin f-Jeidelberg 1984 Softcover reprint of the hardcover 1st edition 1984 2145/3140-543210 CONTENT Introduction speech Erik ASMUSSEN, The Netherlands General papers on conflict technique development and application A. S. HAKKERT, Israel 7 V.A. GÜTTINGER, The Netherlands 17 G.B. GRAYSON, Uni ted Kingdom 25 M.O. MATTS ON , Sweden 35 Technical papers on conflict techniques J. MIGLETZ and W.D. GLAUZ, USA 41 C.J. BAGULEY, United Kingdom 59 P.J. COOPER, Canada 75 R. KULMALA, Finland 97 H. ERKE, Germany 107 N. MUHLRAD and G. DUPRE, France 121 C. HYDEN and L. LINDERHOLM, Sweden 133 R. RISSER and A. SCHÜTZENHÖFER, Austria 141 U. ENGEL and L. THOMSEN, Denmark 153 R. VAN DER HORST, The Netherlands 189 Background paper for the international calibration study (Malmö, Mai 30th - June 10th) S. OPPE, The Netherlands 199 International calibration study of traffic conflict techniques General design ICTCT Steering Committee 207 Summary of discussions and conclusions N. MUHLRAD, France 211 Closing remarks E. ASMUSSEN, The Netherlands 219 List of abstracts 221 List of participants 229 FOREWORD The concept of traffic conflict was initiated in the Uni ted States in the 60s and raised a lot of interest in many countries : it was an opening towards the develop ment of a new tool for safety evaluation and the diagnosis of local safety pro blems. The need for such a tool was great, because of the many situations where accident data was either scarce, unsatisfactory or unavailable. Development of Traffic Conflict Techniques (TCT) started simultaneously in the 70s in several European count ries and new studies were also undertaken in the Uni ted States, Canada and Israel. The need for international cooperation was rapidly feIt, in order to exchange data, compare definitions and check progresses. An Association for International Cooperation on Traffic Conflict Techniques (ICTCT) was therefore created, grouping researchers and safety administrators, with the aim of promoting and organising exchange of information and common practical work. Three Traffic Conflict Techniques Workshops were organised, in Oslo (1977), Paris (1979) and Leidschendam (1982). A small scale international experiment of calibra tion of TCTs was also carried out in Rouen, France, in 1979, and five teams took part in it from France, Germany, Sweden, the United Kingdom and the United States; results of this first experiment were used as a basis for the present enterprise. To be acknowledged as a safety measuring tool, traffic conflict techniques had to be validated in relation to traditional safety indicators such as injury-accidents. Validation turned out to be a difficult task, requiring a lot of effort on data collection and the design of adequate statistical methods, and results obtained were not fully decisive. The pooling of efforts in this field appeared necessary for further progress and a first step towards it was the calibration of all existing TCTs, i.e. a detailed comparison of definitions, procedures, and type of data collected, in order to be able in the near future to use extended data bases and draw a conceptual framework for validation. The second International Calibration Study was therefore organised in Malmö, Sweden, in June 1983, during which ten different teams would be experimenting their own TCT, simultaneously and on the same locations. Video-films were taken as a reference for all data collected, and a data treatment procedure, including both statistical and detailed comparisons, was designed. A preliminary meeting took place in Copenhaguen on 25 - 27 May 1983, giving all participating teams and interested observers an opportunity to discuss in details existing TCTs, and to finalize and adopt final procedures for the Malmö experiment. This book contains all the papers presented in Copenhaguen, as weIl as a summary of discussions and conclusions. JOINT INTERNATIONAL STUDY FOR THE CALIBRATION OF TRAFFIC CONFLICTS TECHNIQUES Introduction speech ICTCT Meeting Copenhagen, 25-27 May 1983 and Malmö, 30 May-l0 June 1983 Prof. Erik Asmussen Director Institute for Road Safety Research SWOV Leidschendam, The Netherlands Ladies and Gentlemen, Traffic unsafety can be regarded as the whole of existing and potential critical combinations of circumstances, incidents (conflicts) and accidents in traffic and the individual and social consequences (damages) caused by them. The main feature of incidents and accidents is that they are always preceded by a critical combination of circumstances in traffic. Such critical combi nation of circumstances for example in a situation can be described as a situation wherein, with unchanged traffic behaviour and/or unchanged traffic situation, the interaction between man, vehicle, road traffic and environment leads to accidents (see Figure 1). Without taking into account the emotional content of the word, we could simply speak here of a coincidence of circumstances. Such a combination or coincidence of circumstances in a traffic situation is always preceded by decisions, which are jointly determining whether the combi nation of circumstances becomes critical or not. Such decisions may refer to the purpose and scheme of travel, the mode of transport, the speed of the car and the alertness of the road user (provoked traffic behaviour). If in the situation of a critical combination of circumstances, anticipating or "normal" change of behaviour is possible, because the road user recognises the critical (combination of) circumstances in time, there is no problem at all. If there is no anticipating behaviour, or this is not sufficient, an emergency manoeuvre is needed, for instance emergency braking or evasive action. If the emergency manoeuvre is succesful, an incident or conflict is the result. If the emergency manoeuvre fails an accident or collision arises. NATO ASI Series, VoL F5 International Calibration Study of Traffie Confliet Teehniques Edited by E. Asmussen © Springer-Verlag Berlin Heidelberg 1984 2 Figure 1. Model or the accident process Social activities and travel needs / ~ Purpose of travel ~.~----~• • Transport mode < ~ Route and timetable ~vel behavitur~ances in travel situation i ____ --I I Provo!ked traffic behaviour 1 I critical combination of cir~umstances in traffic" situation t Anticioatory traffic behaviour critical combination of circumstances in traffic situation EmerQency (manoeuvre)behaviour / of circumstances in ! ! Incident or conflict Aecident (eollision) critical combination of cri tieal combination of circumstances in incident cireum~tances in eollision situation situati'on Consp.Quences ConseQuenees / Chain~distur~Fright ~ Death, iniury, Chain disturbanee material and environmental damage $ Critieal eombination of cireumstanee ~ in injury situation Recovery (eure, permanent disablement) 3 Both in the "anticipating" phase and in the "emergency" phase critical combi nations of circumstances can affect the outcome. I show you this phase model of the accident process, because we have to make clear to each other about which part of the process we are speaking if we use the word "conflict". Before I shall speak about the importance and usefulness of traffic conflicts techniques, I want to make a comparison between the control of (the unsafety of) the transport at ion system and the steering of a fully loaded mammoth tanker. If the wheel of such avesseI is swung right round, the effect (the output) will not become noticeable for some time. The slow response by the tanker is comparable with the slowness of accident registration. The limitation of human perception abilities in noting slow (slight) changes is comparable with the limitations of statistical analysis methods for dis closing changes in the pattern of accidents. The moment the changes in output are observed, it is often too late both on the tanker and in the transportation system to make effective corrective action. Masters of giant tankers therefore do not respond so much to changes in the vessel's course (output variable; cf. accident statistics), but predict changes in output by responding to data on input and intermediate processes (input and process indicators), such as position of helm, speed, direction and speed of currents, etc. This is possible because they have sufficient knowledge and comprehension of the relationship between control variables and process variables, and the influence this has on changes in output. They do not wait, therefore, until the moment the output (change in course) manifests itself; they certainly do not wait till an accident has happened. In research concerning shipping traffic, as weIl as in aerial traffic, the so called incidents or conflicts or near misses play an important role. Of course that is also because accidents seldom happen, and if they happen, result in tremendous damage. But the main reason is that incidents or conflicts tell us about the critical combinations of circumstances in this traffic. In shipping and aerial systems, they even use this knowledge for training purposes. In research it is the most important sour ce of information. 4 The cha11enge of this experiment that we are all concerned with, regarding the ca1ibration of traffic conf1icts techniques (TCT's), is to make c1ear the importance and usefu1ness of these techniques for the improvement of traffic safety. If we do not succeed in this, then we will fai1 regard1ess the interesting technica1 resu1ts. In many countries we find examples of the app1ication of the TCT. However, the app1icabi1ity is restricted and often restricted to experimental use. In various countries, however, there is a need for operationa1 use on a 1arger and more general sca1e. Sweden is one examp1e of this. Mr. Mattson will give us a description of the background of this need. His problem as he states it in his paper is not so much the detection of dangerous 10cations but the analysis of the safety problem. The accident data are too scarce for a detai1ed analysis and the information stored in the accident report often misses the relevant cues to reconstruct what exact1y did happen. The Swedish conf1ict technique will be used to co11ect more information about the safety problems at specific locations. In The Nether1ands, but I think also in many other countries, we fee1 the same need for additional information in order to make an analysis of traffic safety, and also in our country we look for a technique that is systematic and easy to use. In the USA, as can be seen from the paper of Mr. Mig1etz and Mr. G1auz, one is a 1ittle bit dissatisfied about the app1icabi1ity of the TCT for safety analysis purposes. They 10wered their aims and made the technique app1icab1e in order to detect "operationa1 deficiencies" as they ca11 it. A concept that is re1ated to dis comfort and feelings of unsafety that also can be regarded as negative aspects of transportation. But also in the Uni ted States there is a need for such an easy-to-use technique to solve safety problems. This brings us to the very heart of the problem: How relevant is the analysis of traffic conf1icts for the analysis of traffic safety? So far I mentioned two kinds of usage of the conf1ict analysis technique: The detection of dangerous locations and the diagnosis of the safety problem. An administrator, however, who is in charge of the safety of a road network, is primari1y interested in the app1ication of the technique with regard to the solution of the safety problem he has detected and analysed. He wants to know how to contro1 safety. If the diagnosis leads to a conc1usion about what is wrong at a particu1ar 10cation, then this does not lead direct1y to a solution of this safety problem. Various safety measures can be taken in order to solve the ~afety problem. It is not necessary that the app1ication of these measures leads to a definite solution of the problem at hand. Measures often have side-effects. They may inf1uence the situation in more than one way. Road surface improvements may attract traffic, traffic signals may cause changes in