MOTORCYCLE ACCIDENT CAUSE FACTORS AND

TABLE OF CONTENTS 086.96.106.116.126.136.14FACTORSMotorcycle Size and TypeManufacturer of the Accident-Involved Motorcycleyear of Msnufaeture, or Model YearPredominating Color of the MotorcycleCollision Contact on the MotorcycleMotorcycle ModificationsFuel System CrashworthinessPre-Crash and Crash SpeedsContributory Tire ConditionsCornering ClearancePm-Crash Line-of-SightCrash Bar EffectivenessVehicle DefectsOther Vehicle Involved in the Accident With theMotorcycleMOTORCYCLE RIDER, PASSENGER, AND OTHER VEHICLE DRIVERCHARACTERISTICS7.1Motorcycle Rider AgeMotorcycle Rider Sex, Marital Status, Children7.27.3Motorcycle Rider Height and Weight7.4Motorcycle Rider Occupation and EducationMotorcycle Rider License Qualification7.57.6Motorcycle Rider Traffic Violation and AccidentExperience7.7Motorcycle Rider Training Experience7.8Motorcycle Rider Dirt Bike Experience7-9Motorcycle Rider Street Bike Experience7,lOMotorcycle Rider Familiarity with Roadway7-11Motorcycle Rider Hand Preference7.12Motorcycle Rider Alcohol and Drug Involvement7.13Motorcycle Rider Physiological Impairment7.14Motorcycle Rider Characteristics, Tattoos7.15Motorcycle Rider Performance, Rider Attention toDriving Task7.16Motorcycle Rider Performance, Rider Stress onDay of Accident7.17Motorcycle Rider Collision Avoidance Performance7.18Motorcycle Rider Loss of Control7.19Motorcycle Passenger Sex7.20Motorcycle Passenger Height and Weight7.21Motorcycle Passenger Occupation7.22Motorcycle Passenger Experience7.23Motorcycle Passenger Alcohol and Drug Involvement7.24Other Vehicle Driver Age7.25Other Vehicle Driver Sex, Marital Status, Children7-26Other Vehicle Driver Education and Occupation7.27Other Vehicle Driver License Qualification7,28Other Vehicle Driver Experience7-29Other Vehicle Driver Alcohol and Drug 40150155155156156157157157161162162166

-TABLE OF CONTENTS (Continued)Page8.09.0--HUMAN FACTORS - INJURIESInjuries - General Characteristics8.1Rider and Passenger Positions on the Motorcycle8,2at Crash ImpactMotorcycle, Rider and Passenger Motion After8.3Collision ContactOn-Scene Medical Assistance and Injury Status,8.4Motorcycle Rider and Passenger8.5Somatic (Body) Region Injuries8.6Head and Neck Injuries (Including Face)8.7Injury Mechanisms, Contact Surfaces8.8Injury Association: Effects of Speed, Alcohol Involvement, and Motorcycle Size on Injury SeverityGroin Injuries8.9169169HUMAN FACTORS-PROTECTION SYSTEM EFFECTIVENESSProtection Systems - GeneralCharacteristics,Helmets9.19.2Eye Protectionsafety Helmet use Characteristics9.3Helmet Manufacturer and Construction9.4Safety Helmet Retention System Performance9.5Safety Helmet Weight9.6Safety Helmet Color9.7Safety Helmet Impact Analysis9.8Safety Helmet-Effectiveness: Head and Neck Injury9.9Type of Lesion9.10Safety Helmet Effectiveness: Head and Neck InjurySeveritySafety Helmet Effectiveness: Overall Severities9.11Sum (SS) and Head and Neck Severities Sum (SS2)Safety Helmet Effectiveness: Head and Neck Injury9.12RegionSafety Helmet Effectiveness: Neck Only Injury Severity9-13Effect of Helmet Coverage on Motorcycle Rider Most9.14Severe Head InjuryEffect of Helmet Coverage on Motorcycle Rider9.15Most Severe Face InjuryEffect of Helmet Coverage on Motorcycle Rider9.16Most Severe Neck InjuryEffect of Eye Protection on Motorcycle Rider9,17Most Severe Face InjuryEffect of Eye Protection on Motorcycle Rider9.18Most Severe Eye InjuryMotorcycle Rider Most Severe Injury, Somatic Regions9.199.20Effect of Upper Torso Garment on Most Severe UpperTorso InjuryEffect of Lower Torso Coverage on Most Severe9.21Lower Torso InjuryEffect of Foot Coverage on Most Severe Ankle-Foot9.22InjuryEffect of Hand Protection on Most Severe Hand 12316319

TABLE OF CONTENTS (Continued)Page9.249.259.269.279.2810.011.0Helmet Use Related to Hearing Critical Traffic SoundsInjuries Attributed to Safety HelmetsRider Fatigue and Helmet UseSafety Helmet Performance Related to FMVSS 218Videotape and Movie Film ProjectEXPOSURE DATAEnvironmental Factors10.1Rider Trip Plan10.2Time Riding Motorcycle Before Interview10.3Median Traffic Flow10.4WeatherVehicle Data10.5Motorcycle Size and Type10-6Manufacturer of Motorcycles10.7 Year of Manufacture, or Model Year10.8Predominating Color of the Motorcycle10.9Motorcycle Modifications10.10 Headlamp UsageHuman Factors10.11 Motorcycle Rider Age10.12 Motorcycle Rider Sex, Marital Status, Children10.13 Motorcycle Rider Height and Weight10.14 Motorcycle Rider Occuuation and Education10.15 Motorcycle Rider Lice;se Qualification10.16 Motorcycle Rider Traffic Violation and AccidentExperience10.17 Motorcycle Rider Training Experience10.18 Motorcycle Rider Dirt Bike Experience10.19 Motorcycle Rider Street Bike Experience10.20 Motorcycle Rider Familiarity with the Roadway10.21 Motorcycle Rider Hand Preference10022 Motorcycle Rider Alcohol and Drug Involvement10.23 Motorcycle Rider Permanent Physiological Impairment10.24 Motorcycle Rider Tattoos10025 Motorcycle Rider Attention to Driving Task10.26 Motorcycle Rider Stress on Day of Interview10.27 Motorcycle Rider Stated Front Brake Use10.28 Motorcycle Passenger Involvement10.29 Motorcycle Rider and Passenger Protective Equipmentlo-30 Sample Population Data From Motor Vehicle andDriver License RegistryCOMPARISONS OF ACCIDENT AND EXPOSURE DATAConspicuity Factors11.1Motorcycle Size-Engine Displacement11,2Motorcycle Color11.3Motorcycle Modifications Which Affect Conspicuity11,4 Headlamp Use3233243 23243273293 82382382383384385vi-

TABLE OF CONTENTS (Continued)PageHigh Visibility Upper Torso GarmentHelmet ColorMotorcycle Rider Licensing and TrainingDriver License Qualification11.7Motorcycle Rides Training Experience11.8Motorcycle Rider Street Bike Experience11.911.10 Dirt Bike ExperienceMotorcycle Rider Characteristics11.11 Motorcycle Rider Age11.12 Motorcycle Rider Sex, Marital Status, Children11.13 Physical Characteristics11.14 Motorcycle Rider Education and Occupation11.15 Motorcycle Rider Attention, Stress and PhysiologicalImpairment11.16 Alcohol and Drug Involvement11.17 Tattoos, Hand Preference11.18 Motorcycle Rider Driving Record11.19 Route Familiarity, Trip Plan, and Motorcycle Use11.20 Motorcycle Rider Protective EquipmentVehicle Factors11.21 Motorcycle Manufacturer11.22 Motorcycle Size-Engine Displacement11.23 .Motorcycle Type11.24 Motorcycle ModificationsCharacteristics of the Other Vehicle Driver11.25 Age and Sex11.26 Other Vehicle Driver License Qualifiwtionand Driving Experience11.27 Alcohol and Drug Involvement11.28 Other Vehicle GS, P.ECOMMENDATIONS AND PROPOSED COUNTERMEASURES12.1Findings12.2Recommendations and Proposed Countermeasilres(Training, Licensing, Law Enforcement, ProtectiveEquipment, Conspicuity, Federal Motor Vehicle -----VOLUME II - APPENDIX AND SUPPLBMEKl'AL DATAA.TERMINOLOGYB.FIELD DATA COLLECTION FORMSC.SUPPLEMENTAL ACCIDENT DATAD.SUPPLEMENTAL EXPOSURE 14414

1.0 SLWRY1.1 Objectives--Motorcycle accidents are a very special and severe problem. Thefatalities due to motorcycle accidents are approaching five thousand per year,and have the prospect of further increase unless effectfve countermeasures areinstituted. At present time motorcycle accidents account for approximatelyten percent of the total traffic accident fatalities, but the motorcycle isonly one to two- percent of the vehicle population on the street in traffic.The objectives of this research were to conduct a detailed investigationand analysis of a large number of motorcycle accidents with a highly specialized multidisciplinary research team. In this way, complete engineering andmedical information could be collected and all of the accident events could bereconstructed to determine accident and injury causes. This scientific, multidisciplinary approach could provide much more exact and complete informationthan was available from police traffic accident reports.Three specific areas were set as objectives in this research:1. The causes of motorcycle accidents and injuries need to be determined accurately so that all contributions of'the motorcycle rider, cardriver, roadway features and motorcycle desi&n are defined.2. The effectiveness of safety helmets, and other protective equi?me"t,must be determined because the motorcycle rider has no crash protection unlessit is being worn on the body.-3. Countermeasures must be determined which will prevent motorcycleaccidents and reduce injuries. Most accidents are preventable, and motorcycle accidents are unique and different but preventable if the causes andcures are knoun. The purpose of this research was to determine exactly thosecauses and cures.1.2 Hethodology-.--This research was conducted in Los Angeles, California from July, 1975until September, 1980, at the Traffic Safety Center of the University ofSouthern California. A specialized research team was formed with engineers,psychologists, medical doctors and data processing specialists. All membersof this research team were required to have motorcycle riding experience sothat they could appreciate and understand all hazards peculiar to the motorcycle and its accident problems. This research team underwent six months ofspecial training to achieve a high capability in reconstructing motorcycleaccidents, examining accident helmets, evaluating injuries, interviewing witnesses, etc. I" addition, cooperation was obtained from the law enforcementagencies, fire department rescue ambulance services, hospitals and the medical examiner-coroner, so that the research team could have access to accidentscenes, interview victims and witnesses, and collect injury information.1

During 1976 and 1977, the motorcycle accident research team conductedon-scene, in-depth investigations of more than 900 motorcycle accidents by goingto the accident scene at all times of the day and all days of the week. Eachaccident was completely reconstructed and approximately a thousand dataelements were determined for each accident. Also, 3600 police traffic accident reports were collected in the same area at the same time for comparisonwith the 900 on-scene, in-depth accident investigations.During 1978 and 1979, these accident cases were analyzed and exposuredata were collected at 505 of the 900 accident sites. The research teamsreturned to the accidentsites at the same time of day, same day of the weekand same weather conditions, end interviewed 2310 motorcycle riders and examinedtheir motorcycles. Information was collected about training, experience, education, helmet use, alcohol and drug use, etc. for all of these motorcycleriders who were at the same place at the same time of day but not- involved inan accident.The accident data from the 900 on-scene, in-depth cases were analyzed todetermine accident and Injury causes. Then the exposure data was comparedwith the accident data to determine what factors were outstanding. For example,only 30% of the motorcycles in the accident data had the.headlamp on in daylight, but hO% of the motorcycles In the exposure data had the headlamp on indaylight. This comparison identifies the use of the motorcycle headlamp on indaylight as a powerful and effective way of reducing accident involvement, bymaking the motorcycle more conspicuous in traffic.Motorcycle accidents that occur in Los Angeles are essentially the same asmotorcycle accidents occurring in other locations in the United States. Themost frequent use of a motorcycle is in favorable weather because there Is noprotection for the motorcycle rider in bad weather and the motorcycle lacksstability on slippery roadways. Also, most motorcycle accidents occur in favorable weather simply because of the more frequent use, and human error predomhates in those accidents. The motorcycle accidents studied in Los Angeles areessentially the same as motorcycle accidents occurring in other locations inthe United States; ihe Los Angeles area simply had MORE motorcycle accidentsavailable to investigate and study.1.3 Research FindingsThe most common motorcycle accident involves another vehicle causing thecollision by violating the right-of-way of the motorcycle at an intersection,usually by turning left in front of the oncoming motorcycle because the cardriver did not see the motorcycle. The motorcycle rider involved in the accident is usually inconspicuous in traffic, inexperienced, untrained, unlicensed,unprotected and does a poor job of avoiding the collision.The data of this accident research provide the following principalfindings:1. Accident and Injury Causes. The automobile driver falls to detectthe inconspicuous motorcycle in traffic. This is due to the lack of motorcycle conspicuity and lack of caution and awareness of the automobile driver.-

-The lack of skill and traffic strategy increases the motorcycle rider'sinvolvement in collisions. injury severity increases with collision speed,but the motorcycle rider's lack of head protection accounts for the mostsevere but preventable injuries. Also, motorcycle rider lack of collisionavoidance skills increases injury severity.2. Protective Equipment. The only significant protective equipment isthe qualified safety helmet, and it is capable of a spectacular reduction ofhead injury frequency and severity. The Federal Motor Vehicle Safety Standard218 provides a highly qualified safety helmet for "se by motorcycle riders.This research shows NO reasons for a motorcycle rider to be without a safetyhelmet; qualified helmets do not limit vision or hearing in traffic or causeinjury.--.3. Co"ntermeas"res. The basic Motorcycle Rider Course of the MotorcycleSafety Foundation is effective in training motorcycle riders and those trainedriders are both less involved and less injured in motorcycle accidents. Thiscourse--or its equivalent--should be made a prerequisite, or at least acorequisite, of motorcycle "se and should be applied in driver Improvementfor those motorcycle riders vho have received traffic citations. Licensing ofmotorcycle riders must be improved with special motorcycle licenses andimproved testing such as has been developed by NHTSA-Traffic Safety Programs.Law enforcement should act to enforce license requirements, identify alcoholinvolved motorcycle riders, remove dirt bikes from traffic, and effectivelycite and file against culpable accident-involved automobile drivers as well asmotorcycle riders.Most motorcycles in accidents are inconspicuous, and the "se of the headlamp on in daylight and high visibility jackets definitely reduces accidentinvolvement. The "se of a qualified safety helmet reduces head injuries significantly and the accompanying eye protection attached to the helmet preserves vision and reduces accident involvement.All motorcycle riders need training, licensing. citation-related driverimprovement, headlamps on at all times, bright upper torso garments, and headand eye protection to reduce accident involvement and injury frequency andseverity.--3

.2.0 INTRODUCTION2.1 Historical OverviewThe "se of the motorcycle in traffic has increased greatly in recent time.During the last ten years, motorcycle registrations have more than doubled and,unfortunately, the number of motorcycle accidentsxnd injuries has increasedby approximately the same factor. The most recent statistics show that thenumber of fatalities attributed to motorcycle traffic accidents is approachingfive thousand per year. At present ,time, motorcycle accidents contributenearly 10% of the traffic accident fatalities while motorcycles are only oneor two percent of the vehicles In traffic. In this way, the motorcycle appearsto be the most dangerous form of motor vehicle transport.This problem has not escaped notice, and much research has defined theobvious hazard and revealed many of the critical factors in motorcycle accidents. Elementary considerations clearly established the prospects for injuryof the motorcycle rider involved in collision with another motor vehicle,simply because of the lack of a protective envelope available within the conventional automobile. Also, similar fundamental considerations establishedthe beneficial effects of the "se of the contemporary motorcycle safety helmetin preventing and reducing the deadly injuries to the vulnerable head. Inaddition, the lack of conspicuity of the motorcycle in traffic was identifiedes a special problem occurring frequently in accidents, and effectively treatedby the use of the headlamp during daylight and the wearing of high visiblityclothing.A critical contribution to the state of knowledge about motorcycle safetywas the Second International Congress on Automotive Safety, in which theconference theme was Motorcycle and Recreational Vehicle Safety. This conference was sponsored by the National Motor Vehicle Safety Advisory Council ofthe U.S. Department of Transportation and the Society of Automotive Engineers.The literature generated by this activity represented a greet increment ofprogress in motorcycle safety, and provided a true foundation for furtherresearch.In spite of the critical accident factors being identified by pest researchand collected scientific opinions, there was a developing demand for accidentdata to expose the special details of motorcycle accident problems, es well esto substantiate those collected scientific opinions and past research. Therewere important but unanswered questions about motorcycle rider culpability,accident injury mechanisms, safety helmet effectiveness and the possibility ofhelmet-induced injuries, collision avoidance performance of the motorcyclerider, aggressive acts toward motorcycle riders by the drivers of automobiles,and the factors affecting the conspicuity of motorcycles.It became apparent that the most serious questions about motorcycle accidents could not be answered by the research based upon police traffic accidentreports. First, the police traffic accident reports could not he used toextend and synthesize specialized information on accident and injury causation,and second, the reconstruction of motorcycle accidents required knowledge andskills far beyond the activity

section, usually by turning left in front of the oncoming motorcycle because the car driver did not see the motorcycle.The motorcycle rider involved in the accident is usually inconspicuous in traffic,inexperienced, untrained, unlicensed, unprotected and