MOTORCYCLE ACCIDENT CAUSATION AND IDENTIFICATION OF COUNTERMEASURES IN THAILAND VOLUME I: BANGKOK STUDY BY VIRA KASANTIKUL, M.D. CHULALONGKORN UNIVERSITY BANGKOK, THAILAND 10330 SEPTEMBER 2001 FINAL REPORT ISBN: 974-13-1492-2 THIS REPORT OR ANY PART THEREOF, MAY NOT BE REPRODUCED IN ANY FORM WITHOUT THE WRITTEN PERMISSION OF THE AUTHOR. This document was prepared under the sponsorship of Honda R&D (Japan), Asian Honda Co. Ltd. (Thailand) and AP Honda Co. Ltd. (Thailand). The contents of this report reflect the views of the author, which is responsible for the facts and accuracy of the data presented herein. The findings and conclusion do not necessarily reflect the official views of Chulalongkorn University. Table of Contents Table of Contents................................................................................................. 1 Acknowledgements.............................................................................................. 5 1.0 Executive Summary................................................................................... 6 2.0 Introduction.............................................................................................. 10 2.1 Historical overview............................................................................... 10 2.2 Objectives of the research................................................................... 11 2.3 On-scene, in-depth investigations........................................................ 11 2.4 Helmet analysis.................................................................................... 12 2.5 Injury analysis...................................................................................... 13 2.6 Exposure data...................................................................................... 13 2.7 Accident and exposure data comparisons........................................... 14 2.8 Study area............................................................................................ 14 3.0 Development of the Research................................................................. 15 3.1 Technical development........................................................................ 15 3.2 Data forms ........................................................................................... 17 3.3 Project schedule.................................................................................. 18 3.4 Project personnel................................................................................. 20 4.0 Research Methodology............................................................................ 21 4.1 Cooperative agreements...................................................................... 21 4.2 Accident notification............................................................................. 21 4.3 Access to the accident scene............................................................... 22 4.4 On-scene investigation......................................................................... 22 4.5 Environmental evidence....................................................................... 22 4.6 Vehicle evidence.................................................................................. 23 4.7 Human factors...................................................................................... 23 4.8 Injury data............................................................................................ 23 4.9 Helmet acquisition................................................................................ 24 4.10 Accident investigation methodology..................................................... 24 4.11 Quality control...................................................................................... 25 4.12 Data processing and analysis.............................................................. 26 4.13 Research recommendations................................................................ 27 5.0 Accident Characteristics & Environmental Factors.................................. 28 5.1 Investigations....................................................................................... 28 5.2 General accident characteristics.......................................................... 28 5.3 Accident scene..................................................................................... 33 5.4 Other vehicle roadway......................................................................... 39 5.5 Traffic controls..................................................................................... 42 5.6 Traffic density....................................................................................... 43 5.7 Stationary and mobile view obstructions.............................................. 43 5.8 Pedestrian and animal involvement..................................................... 44 6.0 Motorcycle and Other Vehicle Mechanical Factors.................................. 46 6.1 Motorcycle characteristics.................................................................... 46 6.2 Motorcycle tyres and wheels................................................................ 49 6.3 Motorcycle brake system ..................................................................... 52 1 6.4 Motorcycle frame and suspension........................................................ 53 6.5 Motorcycle foot pegs and side stand.................................................... 58 6.6 Motorcycle headlamps......................................................................... 59 6.7 Motorcycle handlebar and throttle........................................................ 60 6.8 Motorcycle fuel system performance and fire hazards......................... 61 6.9 Motorcycle exhaust systems................................................................ 65 6.10 Motorcycle mechanical problems......................................................... 66 6.11 Other vehicle characteristics................................................................ 67 7.0 Motorcycle and Other Vehicle Collision Kinematics................................. 70 7.1 Motorcycle pre-crash motions.............................................................. 70 7.2 Motorcycle pre-crash and crash speeds.............................................. 73 7.3 Pre-crash line-of-sight from motorcycle to other vehicle...................... 76 7.4 Collision avoidance.............................................................................. 79 7.5 Post-crash motion of the motorcycle.................................................... 88 7.6 Other vehicle kinematics...................................................................... 90 7.7 Other vehicle speed............................................................................. 91 7.8 Pre-crash line-of-sight from the other vehicle to the motorcycle.......... 92 7.9 Other vehicle collision avoidance......................................................... 93 7.10 Other vehicle post-crash motion.......................................................... 95 8.0 Human Factors........................................................................................ 97 8.1 Rider, passenger and other vehicle driver general characteristics....... 97 8.2 Rider licensing and training................................................................ 101 8.3 Rider motorcycling experience........................................................... 102 8.4 Experience carrying passengers and cargo....................................... 105 8.5 Rider’s prior violation and accident experience.................................. 106 8.6 Rider trip............................................................................................ 107 8.7 Physiological impairment................................................................... 109 8.8 Alcohol............................................................................................... 110 8.9 Rider attention to driving task............................................................. 113 8.10 Countermeasures recommended by rider.......................................... 113 8.11 Motorcycle passengers...................................................................... 114 8.12 Passenger licensing and experience.................................................. 114 8.13 Passenger physiological impairments................................................ 118 8.14 Passenger alcohol.............................................................................. 118 8.15 Passenger recommended countermeasures..................................... 119 8.16 Other vehicle driver licensing and training......................................... 120 8.17 Driving experience............................................................................. 121 8.18 Other vehicle use pattern................................................................... 123 8.19 Driver’s prior traffic violation and accident experience....................... 123 8.20 Driver trip........................................................................................... 124 8.21 Alcohol............................................................................................... 126 8.22 Driver physiological impairments ....................................................... 126 8.23 Driver recommended countermeasure............................................... 128 9.0 Injuries................................................................................................... 130 9.1 Trauma status.................................................................................... 130 9.2 Injury severity and region................................................................... 131 2 9.3 Rider head injuries............................................................................. 132 9.4 Rider face injuries.............................................................................. 133 9.5 Rider soft tissue neck injuries............................................................ 134 9.6 Rider thorax injuries........................................................................... 135 9.7 Rider upper extremity injuries............................................................ 136 9.8 Rider abdominal injuries..................................................................... 136 9.9 Rider pelvic region injuries................................................................. 137 9.10 Rider spinal column injuries............................................................... 138 9.11 Rider lower extremity injuries............................................................. 138 9.12 Injury contact surfaces....................................................................... 139 10.0 Helmets and Clothing............................................................................ 143 10.1 Helmets.............................................................................................. 143 10.2 Factors affecting helmet use.............................................................. 146 10.3 Helmet characteristics........................................................................ 151 10.4 Retention system design and performance........................................ 155 10.5 Safety helmet Impact analysis........................................................... 159 10.6 Face shields....................................................................................... 161 10.7 Clothing.............................................................................................. 163 10.8 Clothing effect on injuries................................................................... 165 11.0 Contributing Factors in Accident Causation........................................... 168 11.1 Environmental factors........................................................................ 168 11.2 Vehicle factors................................................................................... 173 11.3 Rider alcohol...................................................................................... 174 11.4 Human factors.................................................................................... 183 11.5 Other vehicle contribution to accident causation................................ 190 11.6 Accident contributing factors.............................................................. 193 12.0 Exposure Data....................................................................................... 196 12.1 Environmental factors........................................................................ 196 12.2 Vehicle data....................................................................................... 198 12.3 Human factors at on-scene exposure data sites................................ 199 12.4 Petrol station exposure data.............................................................. 202 12.5 Vehicle factors in petrol station interviews......................................... 203 12.6 General characteristics of riders in petrol station interviews.............. 203 12.7 Licensing and training of riders in petrol station interviews................ 206 12.8 Rider experience................................................................................ 206 12.9 Rider’s previous traffic violations and accidents................................. 209 12.10 Rider trip......................................................................................... 209 12.11 Physiological impairments and stress............................................. 211 12.12 Rider alcohol use............................................................................ 212 12.13 Helmet use..................................................................................... 212 12.14 Factors affecting helmet use .......................................................... 215 12.15 Protective clothing.......................................................................... 219 12.16 Motorcycle passengers................................................................... 221 13.0 Comparison of Accident and Exposure Data......................................... 222 13.1 Accident characteristics..................................................................... 222 13.2 Motorcycle characteristics.................................................................. 223 3 13.3 Alcohol involvement........................................................................... 225 13.4 Rider license qualification.................................................................. 226 13.5 Rider general characteristics.............................................................. 226 13.6 Rider training...................................................................................... 229 13.7 Rider experience................................................................................ 230 13.8 Previous traffic violations and accidents............................................ 232 13.9 Rider trip............................................................................................ 234 13.10 Physiological impairments.............................................................. 236 13.11 Helmet use..................................................................................... 237 13.12 Summary of accident – exposure comparisons.............................. 238 14.0 Comparison of Accidents in Bangkok and Upcountry........................... 240 14.1 Accident characteristics..................................................................... 240 14.2 Motorcycle characteristics.................................................................. 245 14.3 Rider characteristics........................................................................... 246 15.0 Findings................................................................................................. 250 16.0 Proposed Countermeasures.................................................................. 255 16.1 Training.............................................................................................. 255 16.2 Licensing............................................................................................ 255 16.3 Law enforcement and record keeping................................................ 256 16.4 Environment factors........................................................................... 257 16.5 Vehicle factors................................................................................... 258 16.6 Protective equipment......................................................................... 259 17.0 References............................................................................................ 261 Appendix A....................................................................................................... 262 Appendix B (Statistical analysis)...................................................................... 269 Appendix C (Motorcycle components).............................................................. 272 4 Acknowledgements We wish to express our thankfulness to the following persons who contribute actively to the achievement of this research project. ?? Honda R&D, Asian Honda Co, Ltd. (Thailand) and A-P Honda Co, Ltd. (Thailand) supported this work. ?? Professor Dr. Thienchay Kiranandana, former President Chulalongkorn University for his support that was critical to this research project. ?? Chief of Royal Thai Police, Bangkok Police Commissioner, and all districts police for their cooperation and assistance, which were vital to this on-scene investigation project. ?? Chief of Institute of Forensic Medicine, Police Department, and chiefs of Department of Forensic Medicine, Ramathibodi Hospital, Siriraj Hospital, Vachira Hospital and King Mongkut Hospital for the support and assistance which contributed significantly to this research project. ?? Dr. Somchai Kanchanasut, Director of Narenthorn Communication and EMS Center, Dr. Chaiwan Charoenchoketavee, Chief of Emergency Department, Vachira Hospital, and their emergency medical service crews who provided much help to the research team. Their contributions were vital to the collection of on-scene accidents in the Bangkok study area. ?? All directors, physicians and the emergency nurses of all involved hospitals who provided great assistance to the research team. Their kind support proved to be critical to the collection and analysis of the injury data and this help was given with clear support for scientific accident research. ?? Professor Dr. Suchada Kiranandana who gave valuable guidance in the statistic analysis and her assistance was greatly appreciated. ?? All NGO's who provided their assistance at the accident scenes. ?? Dr. Terry A. Smith for his critical reviews and editing of the final reports. ?? Mr. James V. Ouellet gave freely of his own time training in accident investigation and reconstruction and in hundreds of case reviews. His assistance was instrumental in the revision and editing of the final reports. ?? Special thanks to all motorcycle riders, passengers and other vehicle drivers who participated in this research and cooperated with the research team. ?? Dr. Vira Kasantikul kindly thanks his dear wife, Professor Duangjai, and their sons Wadis and Tanit for their patience and unflagging support of the effort required for this study. 5 1.0 Executive Summary A total of 723 on-scene, in-depth accident-involved motorcycles were investigated in Bangkok between December 30, 1998 and December 29, 1999. Approximately 97% of all cases were investigated at the accident location while vehicles, drivers and police were still present. The remainders were investigated within a few hours of the accident. Each investigation was conducted by a team of investigators trained in motorcycle accident investigation and analysis. After the initial investigation, the information collected was analyzed to provide a complete reconstruction of events before, during and after the collision. One week after the accident, investigators returned to the accident scene, where they observed, counted and recorded information about motorcycles and other traffic passing accident scenes. Several months later, they returned to the accident area to conduct interviews with riders who stopped at petrol stations near the accident scene. Such "exposure data" provided a comparison of accident-involved riders to the larger population of riders who were exposed to similar accident risks (by using the same roadways under similar conditions), but who were not involved in an accident. Comparisons between accident and exposure populations helped define the differences between accident-involved riders and others. Rider error was the most frequent primary cause in both single and multiple vehicle accidents. Two problems stand out among the rider errors. The first and most readily defined, is alcohol. Alcohol-involved accident preceded 40% of all accidents reported here. The second problem is less easily defined, but it amounts to poor driving. Half of the accidents involved improper traffic strategy such as following another vehicle too closely, unsafe speed or unsafe position. These errors were not restricted to motorcyclists. Other vehicle drivers sometimes caused accidents by making unsafe turns across the path of a motorcycle they saw approaching but which they assumed would yield to them. Accidents also occurred when other vehicle drivers ignored traffic control signs or obvious view obstruction problems. Mechanical problems with the motorcycle were infrequent and were usually due to poor maintenance. Vehicle problems were generally confined to absent or inoperable components (e.g. headlamp, front brake, rear brake, rear position lamp, stop lamp, rearview mirrors, etc.). No accidents occurred because of parts breaking or failing, side stands left in the down position, stuck throttles or dynamic instability. Problems of roadway design and maintenance contributed to many of these accidents – at least one in eight. Such problems were rarely the sole cause of a motorcycle crash, but were alarmingly frequent, particularly in night accidents. The great majority of design and maintenance problems seen in this study affected all road users, not just motorcycles. About one-eighth of the motorcycle accidents were single vehicle collisions. One-third of all accidents occurred during daylight and 62% at night, 6 usually on unlighted roadways. The most frequent accident configuration was a motorcycle rear-ending another vehicle. Rain was an infrequent cause factor because most riders did not ride in the rain, but in the cases when rain was present it usually contributed to causing the accident. Male motorcycle riders were over 95% of the accident population, and most riders fell into the 21 - 35 age category. The average education level was nine years. About one-third of the riders rode a motorcycle as part of their work (messengers, motorcycle taxi rider etc.) and another one-fourth were service or sales workers. Only 8% were full time students. Alcohol-involved accidents differed markedly from non-alcohol accidents. The differences are quite distinct, and alcohol use was so frequent. Alcohol- involved accidents were three times as likely to be single vehicle crashes, three times as likely to involve loss of control, seven times as likely to involve running off the road, and twice as likely to involve violation of traffic control signals or signs when compared to non-alcohol accidents. Alcohol accidents also occurred at higher speeds (about 15 - 20 km/hr on average). Alcohol-involved riders were less likely to wear a helmet and more likely to be hospitalized or to die as a result of the crash. They were twice as likely to be the principal contributing factor in their accidents, and twice as likely to be the only cause of their accidents. Finally, even their time distributions were different: most alcohol-involved accidents occurred between 10 p.m. and 3 a.m., while most non-alcohol accidents happened between 8 a.m. and 7 p.m. Approximately 17% of the accident-involved riders were unlicensed. Most were self-taught or learned from friends and family and only one rider had any formal training in motorcycle riding techniques and collision avoidance strategies. This lack of training, licensing and knowledge frequently appeared as rider errors in many accidents. Among the unsafe practices that contributed to accidents was riding at night with the headlamp off. This made the motorcycle extremely difficult for other drivers to see. Night accidents in which the other vehicle violated the motorcycle right-of-way were five times as common when the headlamp was off. Modifying the motorcycle electrical system so that the headlamp operates whenever engine is running would be an effective means of preventing this problem and reducing accidents in which the other driver fails to see the approaching motorcycle. In addition, parcel racks on the front of the motorcycle should be re-designed in order to assure that carried parcels carried cannot block the headlamp from being seen by other motorists. About one-third of the accident-involved riders who took evasive action made a proper choice, and 39% were able to carry it out effectively. This points to the need for the development and introduction of a combined braking system to maximize the braking potential for the motorcycle to avoid collisions effectively. More than 70% of the motorcycle's braking force can come from the front wheel, but too many riders used the rear brake only. Rider training might reduce the problem of poor brake utilization before an accident, but a combined braking system may be even more effective. 7 About two-thirds of the accident-involved riders were wearing a helmet at the time of the accident. Helmet use was much lower among passengers: only about 30%. Helmet use declined sharply at night, from 78% during the day to 60% at night. Few riders said they always wear a helmet, and many admitted that they wear one only when they think they might encounter police. Head injuries were about four times as frequent among unhelmeted riders as those who wore their helmet securely enough that it stayed on: 11% versus 2.7%. The upper and lower extremities were injured most frequently, although these injuries were not life threatening in the majority of cases. Injuries to the spine, long bones of lower extremity, and ankle could cause significant disability and impairment. The most deadly injuries were to the chest, head and neck. The results of this study suggest that rider training is really needed. Only one rider in 723 accidents and 2100 "exposure" interviews reported any formal motorcycle training. At present, the only formal training is offered by the Honda Safety Training Center, and most participants are police officers. There appears to be no mechanism for disseminating this valuable knowledge into the larger population. One possibility might be to allow motorcycle riders who have completed a motorcycle safety training program to offer a rider training program. Such a program could provide instruction on traffic laws, safe riding strategies, helmet selection and use, and collision avoidance skills. Such training might be an effective co-requisite for obtaining a motorcycle license or an alternative to a fine for riders who have received a traffic citation. Clearly the present system has no mechanism to provide motorcyclists with accurate and reliable knowledge, strategies and skills needed to protect themselves from harm. Law enforcement should focus primarily on alcohol and licensing. Alcohol- involved riders and unlicensed riders were over-represented in accidents and made up a large portion of the accident population. In addition, the excess involvement of other vehicle drivers who operated their vehicles in dangerous ways (such as violation of traffic control signals or motorcycle right-of-way) with deliberation or ignorance is a great accident contributing cause factor. Strict law enforcement and punitive action are required to impress those riders and drivers with the great hazards of unsafe vehicle operation. Roadway design and maintenance need many improvements. The first suggestion would be better warning signs and guidance through curves, particularly at night. The second suggestion is similar: better warning signs and guidance, and fewer view obstructions, at construction sites. While many such sites are not a problem during daylight hours, they become a big problem at night due to a lack of proper warning lights and reflectors. In Bangkok, some roads were notable for problems that contributed to accidents. Crossing accidents were very frequent along Phaholyothin Road, where there are no right-turn-only signals. Raised medians separating traffic lanes that flow in the same direction on Sri Ayutthaya and Vitthayu Roads, often with view obstructions, contributed to many crashes. Also, throughout Thailand, when pavement reflectors are replaced, they should be replaced with smaller, less aggressive reflectors that do not dent motorcycle rims and cause riders to fall. Improvements in roadway 8