Human Factors as Causes for Road Traffic Accidents in the Sultanate of Oman under Consideration of Road Construction Designs Inauguraldissertation zur Erlangung des Doktorgrades (Dr. phil.) der philosophischen Fakultät II (Psychologie, Pädagogik und Sportwissenschaft) der Universität Regensburg Vorgelegt von Kai Plankermann Burglengenfeld 2013 Erster Gutachter: Prof. Dr. phil. Dr. h.c. Alf Zimmer Engineering Psychology Unit, University of Regensburg Zweiter Gutachter: Prof. Dr. rer. nat. Mark W. Greenlee Institute of experimental Psychology, University of Regensburg 1 Acknowledgement I would like to express my deepest gratitude to my advisor Professor Alf Zimmer for accepting me as his PhD student and for providing me with his continuous support. I would also like to thank Dr. Abdullah Al-Maniri who supported me throughout the data collection in Oman. Also, I owe my gratitude to Aisha Al-Belushia who conducted the interviews at Ibra Hospital. Finally, I would like to thank the following persons for contributing to this thesis in one way or another and apologize to those I forgot to mention. The Engineers Altayeb Al-Harthi, Muhammad Al-Hosny (both Muscat Municipality) and Saleh Al- Shukaili (Directorate General for Road and Land Transportation) for providing the road data; the Drs. Muhamad Zaheerudeen (Khoula Hospital), Salem Al-Abri (Nizwa Hospital) and Ali Al-Dawi (Ibra Hospital) for facilitating the data collection at the hospitals; the Engineers Jochen Zimmermann (IJK Associates), Jens Aalund, Klaus Andersen (both COWI) and Jürgen Piel (STRABAG) for fruitful discussions about road safety in Oman; Muhamad Al-Aamri, Mahmud Al-Khatri, Yousuf Al-Rawahi and Mazin Al-Wahibi for helping me during the data collection; Chantal Blake and Amanda Amarotico for proofreading first drafts of this thesis; Dr. Montasser Abdelghani for translating the German questionnaire into Arabic; my Nissan X-Terra for being a reliable and most importantly safe companion while travelling the ten thousand kilometers through Oman to collect the data for this thesis; and, last but not least, I would like to thank my wife Marlene and my daughter Lina for their patience as well as my parents for their support. 2 “Academic work needs to follow rules of good practice, but we should not confuse rigor with tediousness or objectivity with lack of personality. Academics are still ‘human after all’ – to quote Daft Punk. And beyond the barren scientific facts that academics produce, they have a life, an upbringing, a cultural context they inhabit, with opinions and passions (Hassenzahl, 2010).” 3 Table of contents Executive summary ................................................................................................................................. 8 Part I: Introduction ................................................................................................................................ 10 1. The global burden of RTAs............................................................................................................ 10 2. RTAs in Oman ............................................................................................................................... 10 3. RTA research ................................................................................................................................. 11 3.1 The system approach ............................................................................................................... 12 3.2 Education, enforcement and engineering ................................................................................ 13 4. Objectives and structure .............................................................................................................. 14 Part II: Theory and literature review ..................................................................................................... 18 1. The human factor ......................................................................................................................... 18 1.1 The driving task ........................................................................................................................ 18 1.2 Driving and attention ................................................................................................................ 20 1.2.1 Mental overload ................................................................................................................... 20 1.2.2 Mental underload ................................................................................................................. 22 1.3 Driving and perception ............................................................................................................. 23 1.3.1 Speed perception ................................................................................................................. 23 1.3.2 Time to collision .................................................................................................................... 25 1.3.3 The Useful field of view (UFOV) ........................................................................................... 26 1.3.4 Where do drivers look and what do they see? .................................................................... 27 1.4 Information processing............................................................................................................. 31 1.4.1 Bottom-up and top-down processing .................................................................................. 31 1.4.2 Situation awareness and schemata ...................................................................................... 32 1.5 Driver behavior models ............................................................................................................ 36 1.5.1 Risk threshold models .......................................................................................................... 36 1.5.2 Compensation models .......................................................................................................... 37 1.5.3 Risk avoidance models ......................................................................................................... 38 2. Road design .................................................................................................................................. 39 2.1 The driving task and the road design ....................................................................................... 39 2.2 Road categorization .................................................................................................................. 41 2.3 The self-explaining road (SER) .................................................................................................. 42 2.4 The forgiving road..................................................................................................................... 46 4 2.5 Design elements ....................................................................................................................... 47 2.5.1 Design and posted speed ..................................................................................................... 47 2.5.2 Sight distance ....................................................................................................................... 51 2.5.3 Road signs ............................................................................................................................. 55 2.5.4 Road markings ...................................................................................................................... 59 2.6 Road location elements ............................................................................................................ 61 2.6.1 Transitions ............................................................................................................................ 61 2.6.2 Intersections ......................................................................................................................... 69 2.6.3 Horizontal curves .................................................................................................................. 73 2.6.4 Straight sections ................................................................................................................... 76 2.6.5 Roundabouts ........................................................................................................................ 80 Part III: Human factors .......................................................................................................................... 83 1. Methods ....................................................................................................................................... 83 1.1 Data collection .......................................................................................................................... 83 1.1.1 Ethical approval .................................................................................................................... 83 1.1.2 Participants and selection criteria ........................................................................................ 83 1.1.3 Location and period of data collection ................................................................................. 84 1.1.4 The questionnaire based interview ...................................................................................... 85 1.1.5 Data handling.......................................................................................................................