Blending Distributed Situation Awareness with Self-Explaining Roads
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A User-Centered Approach to Road Design: Blending Distributed Situation Awareness with Self-Explaining Roads Miss Ipshita Chowdhury Thesis submitted for fulfilment for the degree of Doctor of Philosophy Institute of Infrastructure and Environment School of the Built Environment Heriot-Watt University 2014 The copyright in this thesis is owned by the author. Any quotation from the thesis or use of any of the information contained in it must acknowledge this thesis as the source of the quotation or information. ABSTRACT Driving is a complex dynamic task. As the car driver drives along a route they have to adjust their driving technique in accordance with the traffic level, infrastructure and environment around them. The amount of information in the environment would be overwhelming were it not for the presence of stored mental templates, accumulated through training and experience, which become active when certain features are encountered. Problems occur when the environment triggers the incorrect templates, or fails to trigger the correct templates. Problems like these can be overcome by adopting a “self-explaining” (SER) approach to road design. That is to say, purposefully designed roads which trigger correct behaviour. A concept which can help improve the theoretical robustness of the SER approach is Situation Awareness (SA). SA describes how the environment and mental templates work together to ensure drivers remain coupled to the dynamics of their situation. It is a widely researched concept in the field of Human Factors but not in the domain of Self-Explaining Roads (SER), despite the very obvious conceptual overlaps. This thesis, for the first time, blends the two approaches, SA and SER, together. From this the ability to extract cognitively salient features and ability to enhance driving behaviour and their effects on driving behaviour are sufficiently enhanced. After establishing SA as critical to driving through literature review the experiment phase started with determining the source of driver SA. Road environment was found to be of utmost importance for feeding into driver SA. This was also confirmed with the results of the on-road exploratory study. The success of the exploratory study led to large scale naturalistic study. It provided data on driver mental workload, subjective situation awareness, speed profile and endemic feature. Endemic features are unique characteristics of a road which make a road what it is. It was found that not all endemic features contribute to SA of a road system. Therefore through social network analysis list of cognitive salient features were derived. It is these cognitive salient features which hold compatible SA and facilitate SA transaction in a road system. These features were found to reduce speed variance among drivers on a road. The thesis ends by proposing a ‘road drivability tool’ which can predict potentially dangerous zones. Overall, the findings contribute to new imaginative ways road design in order to maximize safety and efficiency. ii DEDICATION To Mom, Dad and Road Safety in India iii ACKNOWLEDGEMENTS I would like to thank my parents for supporting me and my decision to pursue higher studies. I am very grateful that they have waited for me to finish and get home Many thanks are given to my supervisor, Dr. Guy.H.Walker not only for offering me the opportunity to study here but also for his help, research direction and great encouragement during the completion of this work. Thanks are also due to my second supervisor Professor John McCarter for much invaluable help and advice. Next, I would like to express my gratitude to various participants who have been involved in the experimental and naturalistic studies undertaken as part of this thesis. Without them this PhD could not have occurred. I am eternally grateful for each and everyone’s involvement. Special thanks are also due to Mrs Lorraine Loy, Head of Health and Safety at Heriot Watt University who has tirelessly circulated emails of participation around the university and persuaded her husband to participate in it as well. Special thanks go to Mr Les Allan who asked some of his ex-police friends to participate in the experiment. I would also like to thank the academics of School of Petroleum Engineering participated and asked their fellow colleagues to participate Numerous thanks are due to Dr Ailsa Strathie for her specialist assistance during my naturalistic studies. Many thanks are also given to future doctorates Melissa Bedinger, Helen Omole and Samuel Olugbenga for their insightful comments and helpful suggestions in my thesis. I am very indebted to the admin staff of school of built environment (SBE) for their immense help with piles of paper work. Many thanks are also due to all the other PhD students of SBE for their never ending words of encouragement, countless lunches and lots of laugh during my time here. Special thanks to Mrs Fiona Johnson, Ms Tillie Boulogne, Ms Shirley Thomas, Mrs Nicky Donald and Dr. Alistair Donald for their invaluable hospitality and advice. Thank you for always being there for me when I needed the most. Thank you so much for setting such good examples to students and providing international students a home away from home. All of you are indeed blessings to numerous students’ lives. iv TABLE OF CONTENTS TITLE ........................................................................................................................................... I ABSTRACT ................................................................................................................................ II DEDICATION........................................................................................................................... III ACKNOWLEDGEMENTS ..................................................................................................... IV LIST OF FIGURES .................................................................................................................. IX LIST OF TABLES .................................................................................................................. XII TABLE OF ACRONYMS ..................................................................................................... XIII CHAPTER 1 : INTRODUCTION ........................................................................................... 15 1.1 Introduction ........................................................................................................................... 15 1.2 Background to the Research ................................................................................................. 16 1.2.1 Situation Awareness ................................................................................................ 16 1.2.2 Cognitive Compatibility .......................................................................................... 18 1.2.3 Self-Explaining Roads ............................................................................................ 19 1.3 Contribution to Knowledge ................................................................................................... 20 1.5 Research Problem ................................................................................................................. 21 1.5.1 Accident Toll .......................................................................................................... 21 1.6 Research Aims and Objectives ............................................................................................. 22 1.7 Thesis Structure .................................................................................................................... 23 CHAPTER 2 : SITUATION AWARENESS: LITERATURE REVIEW ........................... 27 2.1 Introduction ..................................................................................................................... 27 2.2 What is Situation Awareness (SA)? ..................................................................................... 28 2.3 Three Schools of Thought on Situation Awareness ........................................................... 32 2.3.1. Psychological/ individual perspective ........................................................................... 34 2.3.2. Engineering or computing perspective ......................................................................... 38 2.3.3. Interactionist/Systems/Situation Perspective ................................................................ 40 2.4 Definitions of Situation Awareness ................................................................................ 44 2.5 Theoretical Underpinning ..................................................................................................... 49 2.5.1 Mental Models ............................................................................................................... 49 2.5.2. Schemas ........................................................................................................................ 53 2.5.3 Difference between mental models and schemas .......................................................... 55 2.5.4. Perceptual Cycle ........................................................................................................... 56 2.6 Conclusions ........................................................................................................................... 62 CHAPTER 3 : REVIEW OF MEASUREMENT OF SITUATION AWARENESS MEASUREMENT TECHNIQUES ........................................................................................