Crash Causation & Injury Outcome
Posted here are the major studies conducted to identify the causes of motorcycle crashes. These reports also identify factors not found to be significant contributors (mechanical failure, deliberate hostile action by others, etc.) Most also clearly identify countermeasures or hint at countermeasures, provide extensive demographic data, injury information, effectiveness of attempted evasive action and effectiveness of gear and helmets.
There are several “Summary of Findings” posted below which provide an extensive amount of information in a very brief form.
Also posted below are studies which focus on the type and severity of the injuries to riders and passengers that result when a crash occurs.
Crash Causation Research Studies
This is a SMARTER edited version of an 85 page review of the literature written by Kevin Williams on the subject of the motorcyclist/car crash scenario where the car driver violates the right-of-way of the motorcyclist. In the U. S. this crash scenario is often called a Looked But Failed to See (LBFTS) crash. In the U.K, Australia, and New Zealand this scenario is called the SMIDSY crash for Sorry Mate, I Didn’t See You. The research reviewed dispels the common assumption that car drivers simply don’t look or don’t look hard enough for motorcyclists and helps us understand why common countermeasures such as efforts to increase motorcyclist/motorcycle conspicuity and motorist awareness campaigns have not demonstrated effectiveness. The Science of Being Seen Key Points without references and explanation.
This document provides multiple links to the work of Kevin Williams (author of the Science of Being Seen) on subject of the motorcyclist/car crash scenario where the car driver violates the right-of-way of the motorcyclist . In the U. S. this crash scenario is often called a Looked But Failed to See (LBFTS) crash. In the U.K, Australia, and New Zealand this scenario is called the SMIDSY crash for Sorry Mate, I Didn’t See You. The research reviewed dispels the common assumption that car drivers simply don’t look or don’t look hard enough for motorcyclists and helps us understand why common countermeasures such as efforts to increase motorcyclist/motorcycle conspicuity and motorist awareness campaigns have not demonstrated effectiveness.
2020 – “Why are Powered Two-wheeler Riders Still Fatally Injured in Road Junction Crashes? A Causation Analysis”
An abstract of an analysis suggesting that drivers failing to give way to PTW riders at junctions is still a problem. This may relate to the ‘looked but did not see’ phenomenon. The factors that led directly to the crash (phenotype) was most commonly ‘too high speed’ or ‘too late action’ for the motorcyclist and ‘too early action’ for the other driver.
It becomes more evident that many serious traffic violations are a problem mainly amongst those who ride a motorcycle without a valid driver license. Within this group, other serious traffic offenses are also over-represented. Many of the riders without a license did not own the motorcycle used in the fatal accident. In addition, the motorcycles were often unregistered and uninsured, and are therefore not allowed to be used on the road. One fifth of the riders in this group did not wear a helmet when riding which has been a legal requirement in Sweden since 1975. Furthermore, in the "killed without a driver's license" group, a majority (60 percent) were intoxicated and/or under influence of drugs during 2005-2010.
The risk of suffering a motorcycle accident is still difficult to quantify given the different types of individual riding styles of motorcyclists. Every year, nearly 100 motorcycle accidents occur on Austrian roads , but the rare occurrence of accidents at the same spot makes it difficult to locate risky spots. To tackle these challenges, test riders were gathering data while driving on popular motorcycle routes with a motorcycle equipped with the latest sensor technology in order to collect individual driving dynamics data.
2019 – “Contrasting Crash- and Non-Crash-Involved Riders: Analysis of Data from the Motorcycle Crash Causation Study”
This study examines motorcycle crash risk factors by employing data recently made available from the Federal Highway Administration Motorcycle Crash Causation Study (MCCS). The results of the study suggest that motorcycle crash risks are related to rider age, physical status, and educational attainment. In addition to such factors outside of the rider’s control, several modifiable risk factors, which arguably affect the riders’ proclivity to take risks, were also found to be significantly associated with motorcycle crash risk, including motorcycle type, helmet coverage, motorcycle ownership, speed, trip destination, and traffic violation history.
This is an excellent current comprehensive review of the literature regarding the title topic. The review is written March 5, 2018 by Nathan Rose, Director and Principal of Kineticorp, LLC., (303)733-1888, (720)839-1995, www.nathanarose.com/blog, http://kineticorp.com). Note: SMARTER is providing this contact information as a thank you for the permission to post this article and no endorsement of the LLC or its staff should be implied.
This research examined whether state specific texting/handheld bans significantly influence motorcyclist fatalities. Although research is mixed on the effectiveness of texting/handheld bans for overall traffic fatalities, these findings indicate that motorcyclists are at elevated risk of being a victim of distracted driving and thus could greatly benefit from these policies. This study found a strong ban leads to an 8.8% reduction in the motorcyclist fatality rate and a moderate ban leads to a 5.5% reduction. The study also notes other significant predictors for motorcyclist fatalities including a universal helmet law (18.5% reduction).
This report released by The National Transportation Safety Board (NTSB) on October 2, 2018 analyzed select risk factors associated with the causes of motorcycle crashes and evaluated strategies for crash prevention. The NTSB makes recommendations to the National Highway Traffic Safety Administration, the Federal Highway Administration, the Motorcycle Industry Council, the American Motorcyclist Association, and the Motorcycle Safety Foundation.
2018 – “Current Trends in Motorcycle-related Crash and Injury Risk in Australia by Motorcycle Type and Attributes”
The purpose of this study was to characterize current and future motorcycle related road trauma to guide effective safety interventions and future research. A unique feature of the study was the ability to study factors affecting crash risk and injury outcomes for motorcyclists’ related to motorcycle type and other attributes including engine capacity and power to weight ratio. Crash rates and injury outcomes varied significantly by motorcycle type.
The objective of this research was to determine whether inattentional blindness (IB) can be used to understand the psychological mechanisms around looked-but-failed-to-see (LBFTS) crashes involving motorcycles. IB occurs when an observer looks directly at an object yet fails to see it, thus LBFTS crashes may be a real-world example of IB. The study tests a perceptual cycle model in which motorcycles are detected less frequently because they fall lower on the attentional hierarchy for driving.
This is a PowerPoint presentation providing information regarding the Virginia Tech Transportation Institute Naturalistic Studies, including the Motorcycle Safety Foundation 100 (MSF 100) and the National Highway Traffic Safety Administration 160 (NHTSA 160).
Primary and secondary contributors to the crash were judged based on all available information sources. Analysis of the most frequent contributing factors included separation of cases into single and multi-vehicle crashes. For multi-vehicle crashes the most common crash scenario involved another vehicle failing to give way to the rider, and the primary contributor was a perception failure or traffic scan error on the part of the other road user. A number of secondary factors were found to be significantly associated with human error type (other road user or rider error), including rider age, traffic density, inappropriate speed of the PTW, and a road design issue. For single vehicle crashes, the most common primary contributor was a mis-judgement or control error on the part of the rider, with inappropriate speed as the most frequent secondary contributor.
Overall, in-depth motorcycle collision studies conclude that motorcycle accidents have different characteristics to collisions involving other road user groups. In particular, accidents involving motorcyclists are more likely to include right of way collisions, loss of control on bends and more frequent overtaking and passing maneuvers by motorcyclists. This is a section of a larger report which highlights the main causes of crashes involving motorcyclists, and will help to inform the update of ‘RideSafe: Common Causes of Motorcyclist Crashes’, scheduled to be published on the RoSPA website in 2018.
2017 – “Interactions between Cars and Motorcycles: Testing Underlying Concepts through Integration of On-Road and Simulator Studies”
The first study revealed that motorcyclists’ SA comprises more elements than for car drivers, and strong themes emerged around motorcyclists checking for surrounding traffic and hazards. In study 2 an effect of prevalence on the time taken to detect targets was found, with drivers able to detect high-prevalence targets from significantly farther away than low-prevalence targets. The results show that drivers’ difficulty in perceiving motorcyclists is partially due to the fact that motorcycles are relatively rare on Australian roads and consequently drivers do not expect to see them. Given that artificially increasing the prevalence of motorcycles on the roads is not a practical solution, in future research it would be worthwhile exploring other methods of eradicating prevalence effects.
This is a presentation by Carol H. Tan, Ph.D., Office of Safety Research & Development, Federal Highway Administration at the 2017 SMSA Conference Sept 28, 2017. The Federal Highway Administration (FHWA) Motorcycle Crash Causation Study (MCCS) is the most comprehensive data collection effort to study the causes of motorcycle crashes in the United States in more than 30 years. Data are currently available but not published. It is SMARTER’s understanding that there were not enough participants for the final report to draw any conclusions or recommendations. Request data access here: www.hsisinfo.org
This is the authors’ Master Degree thesis. Low motorcycle conspicuity is believed by many to be causally involved in motorcycle collisions that involve another driver. Because the hypothesis that motorcycles lack conspicuity in traffic is so intuitively appealing and so pervasive, it has never been tested. This work provides an argument against the notion that right-of-way-violation collisions are due to poor motorcycle detection resulting from their low conspicuity and proposes an alternate hypothesis: These collisions seem related to failures in motion-perception which are partially caused by the motorcycle’s approach path in a left-of-lane position which, ironically, is partly intended to increase the motorcycle’s conspicuity. See also, 2014 - “Motorcyclist’s Lane position as a Factor in Right-of-Way Violation Collisions: A Driving Simulator Study”
This paper reports on a naturalistic study which was deployed by the Motorcycle Safety Foundation (MSF) to investigate safe riding and crashes in natural riding. Over 366,000 miles of riding were collected by 100 participants on their personal motorcycles. This paper identifies twelve (12) factors that increased risk and five (5) factors decreased risk for riders based on observed crashes and near-crashes.
2014 – “Motorcyclist’s Lane position as a Factor in Right-of-Way Violation Collisions: A Driving Simulator Study”
A driver turning left and failing to notice an oncoming motorcyclist until too late is the most common cause of motorcycle collisions. Consequently, much previous research has focused on motorcycle properties, such as size, shape, and color to explain its inconspicuousness. However, collision statistics remain largely unchanged, suggesting that the issue may not be related solely to the motorcycle’s static properties. In this study, the authors examined a different characteristic of the motorcycle, namely its trajectory of approach. Results show that drivers are more likely to turn in front of an oncoming motorcycle when the motorcyclist is traveling in the left-of-lane position than when it travels in the right-of-lane position. See also 2016 - The Role of Lane Position in Right-of-Way Violation Collisions Involving Motorcycles which is the Master of Arts thesis of the lead author.
2013 – “Driver Inattention and Driver Distraction in Serious Casualty Crashes: Data from the Australian National Crash In-depth Study”
Driver inattention and driver distraction represent a major problem in road safety. Although both are believed to contribute to increased crash risk, there is currently limited reliable information on their role in crashes. The current study used in-depth data from the Australian National Crash In-depth Study to investigate the role of driver distraction and inattention in serious casualty crashes. The most common subtypes of inattention were restricted attention, primarily due to intoxication and/or fatigue, and diverted attention or distraction. The most common types of distraction involved voluntary, non-driving related distractions originating within the vehicle, such as passenger interactions.
This study examined motorcyclist speeds at intersections and concluded that in urban areas motorcycles are traveling significantly faster than other traffic. These findings are discussed against a concern to reduce motorcycle crashes at intersections where the car driver is deemed ‘at fault’.
Previous research on motorcycle crashes has shown the frequency and severity of accidents in which a non-priority road user failed to give way to an approaching motorcyclist without seeing him/her, even though the road user had looked in the approaching motorcycle's direction and the motorcycle was visible. These accidents are usually called “looked-but-failed-to-see” (LBFS) accidents. This article deals with the effects that the motorcyclist's speed has in these accidents.
Two major causes of such a crash scenario are the lack of motorcycle conspicuity and motorist's speed/distance judgment error, respectively. Although various conspicuity aids have proven effective, some researchers reported that motorcyclist's/motorcycle's brightness per se may be less important as a determinant of conspicuity than brightness contrast between the motorcyclists and the surroundings. Research examining the effects of conspicuity measures on motorists' speed/distance judgments when confronting motorcycles has been rather inconclusive.
Ohio crash data for 2003-2007 were used to investigate the odds of a motorcyclist being fatally injured in a crash and the risk factors involved. The results show that risk factors for fatality/severe injury significantly increase when the following circumstances apply: the motorcyclist is a female, being the motorcycle rider, use of excessive speeding, use of alcohol and/or drugs, riding without helmet, being involved in a single-vehicle crash or at a nonintersection location, crashing on horizontal curves or on graded segments, and on major roadways.
Studies of accident statistics suggest that motorcyclists are particularly vulnerable to collisions with other vehicles which pull out of side roads on to a main carriageway, failing to give way to the approaching motorcycle. Why might this happen? The typical response of the car driver is that they looked in the appropriate direction but simply failed to see the motorcycle. To assess the visual skills of drivers in such scenarios we compared the behavior of novice and experienced drivers to a group of dual drivers (with both car and motorcycle experience).
A NHTSA comprehensive, in-depth Motorcycle Crash Causation Study (MCCS) designed to provide a better understanding of motorcycle crashes in order to develop more appropriate countermeasures. When completed, a large and unique data set will be developed that is derived from both actual motorcycle crashes and riders with similar risk characteristics and will focus on the unique circumstances that produce motorcycle crashes.
Summary of Findings regarding the role of the motorcyclist from Fatal Two-Vehicle Motorcycle Crashes.
A NHTSA report that analyzed fatal two-vehicle motorcycle crashes for trends and crash characteristics using FARS data of crashes in 2005, including findings as to the role motorcycle operators played in crash causation.
A study to compare the findings of the European Motorcycle Accident In-Depth Study (MAIDS) with data from the UK On The Spot (OTS) study, which collected all road accident "on-the-spot" data from France, Spain, Germany, Italy, and The Netherlands.
2006 – “Investigation into ‘A’ Pillar Obscuration: A Study to Quantify the Problem Using Real World Data”
The scope of this study was to assess if there is a problem caused by car ‘A’ pillar obscuration in the real world and, if so, to start to quantify the size of that problem. This was achieved by using real world crash data to construct 3-D visualizations that would provide a graphical illustration of the obscuration caused by the car ‘A’ pillar. The report found there is not enough evidence at this stage to suggest changes to the current legislation. However, the EC legislation currently assesses cars based on a 50th percentile male and the visualizations have suggested consideration could be given to smaller and larger drivers. The study recommends that further work.
Twenty-six significant findings.
U.K. Department of Transport. A sample of 1,790 accident cases was considered, including 1,003 in detail, from Midland police forces, involving motorcyclists of all ages, and covering the years 1997 – 2002 inclusive.
Forty-eight significant findings.
2001 – “Motorcycle Accident Causation and Identification of Countermeasures in Thailand. Volume II: Upcountry”
A total of 359 on-scene, in-depth accident-involved motorcycles were investigated in five provincial sampling regions.
2001 – “Motorcycle Accident Causation and Identification of Countermeasures in Thailand. Volume I: Bangkok Study”
A total of 723 on-scene, in-depth accident-involved motorcycles were investigated in Bangkok.
Fifty-five significant findings.
The report is known by the last name its primary author, Professor Harry Hurt. The full title of the report is Motorcycle Accident Cause Factors and Identification of Countermeasures, Volume 1: Technical Report. The findings significantly advanced the state of knowledge of the causes of motorcycle accidents, in particular pointing out the widespread problem of car drivers failing to see an approaching motorcycle and precipitating a crash by violating the motorcyclist's right-of-way. The study also provided data clearly showing that helmets significantly reduce deaths and brain injuries without any increased risk of accident involvement or neck injury.
Crash Injury Outcome
If you crash, which body parts will you most likely injure? This group of studies is focused on the type and severity of the injuries to riders and passengers that result when a crash occurs. Additional research regarding head, brain, neck and spine injuries can be found in the Helmet Research section.
Crash Injury Outcome Research Studies
2021 – “Motorcycle Autonomous Emergency Braking (MAEB) Employed as Enhanced Braking: Estimating the Potential for Injury Reduction using Real-world Modeling” – ABSTRACT
This study is a follow-up to the field-tests on Motorcycle Autonomous Emergency Braking system (MAEB) which showed that higher levels of deceleration to improve its effectiveness were feasible. However, the potential of MAEB in mitigating rider injuries is not well understood, particularly in scenarios where the efficacy of standard MAEB is limited because the rider is manually braking. The purpose of this study was first, to assess the injury mitigation potential of MAEB and second, to test MAEB as an enhanced braking system applied in circumstances where the rider is braking before a crash. The findings estimate the degree to which MAEB could mitigate motorcycle crashes and reduce injury risks for motorcyclists.
The survey was disseminated throughout Europe, the USA, Asia, Australia and South America in order to get as much of a global response as possible. The study extends and expands a pilot study based on a survey of motorcyclists whose motorcycles were fitted with the technology of Advanced (anti-lock) Braking Systems (ABS), which was carried out in 2016/2017. The survey’s overall results highlight the relationship between speed, protective equipment, assistance systems and injuries, as well as how post-crash motions change the patterns of crash occurrence and injury outcome.
2020 – “Optimized Protective Clothing for Motorcyclists: Which Safety Benefit can Airbag-Clothes Deliver?”
The regions of the body most often affected in motorcycle accidents were identified initially following an analysis of the available accident data. Taking the results of the analyses together, it is clear that today’s commercially available thorax airbags can mitigate injuries at lower speeds of impact. The higher the speed of the impact and the smaller the radius of the object involved in the impact, the smaller is the protective effect that can be expected. As of a speed of impact of at most 50 km/h, no appreciable mitigation of injury severity can be expected. Even a significantly optimized airbag, which can still have a protective effect in this speed range, is no longer effective as of a speed of impact of at most 70 km/h.
2020 – “Motorcyclist pelvis interaction with the fuel tank in frontal crashes – a laboratory test method.”
Pelvic injury is common among hospitalised motorcyclists. The primary mechanism is contact with the fuel tank. Injury outcome likely relates to the design of the fuel tank and may also be influenced by the posture of the rider. Currently there is no accepted physical test method for studying this. This study aimed to develop a physical test method for replicating pelvis-fuel tank impacts in frontal motorcycle crashes and to investigate changes in initial pelvic posture.
2018 – “The Danger Zone: Injuries and Conditions Associated with Immediately Fatal Motorcycle Crashes in the State of Michigan.”
Immediately fatal motorcycle crashes have not been well characterized. This study catalogues injuries sustained in fatal motorcycle crashes and assesses the impact of crash conditions on injury patterns. The two most prevalent injuries were traumatic brain injury (TBI) (85%) and rib fractures (79%). The majority of fatalities occurred in daylight hours (54.3%) and in a 55 mph speed limit zone (63.8%). This study provides a catalogue of the injuries sustained in immediately fatal motorcycle crashes and the associated conditions. Advocacy efforts that highlight the risks associated with motorcycle riding and that promote safe riding practices are warranted.
Researchers found that each registered motorcycle in Ontario costs the public health care system 6 times the amount of each registered automobile and conclude medical costs may provide an additional incentive to improve motorcycle safety.
2016 – “Correlation Between Crash Avoidance Maneuvers and Injury Severity Sustained by Motorcyclists in Single-vehicle Crashes”
Abstract. In order to improve motorcycle safety, this article examines the correlation between crash avoidance maneuvers and injury severity sustained by motorcyclists, under multiple precrash conditions. To improve motorcycle safety, training/educational programs should be considered to improve safety awareness and adjust driving habits of motorcyclists.
Not a research article but a well-written overview of the major research on the topic. Published in RideApart.
2013 – “Injury Severity and Causation Factors of Motorcyclists in Traffic Accidents in comparing Drivers of Motorcycle and All Kinds of Motorized Two-Wheelers”
This study describes the injury frequency and injuries in detail for motorcycle drivers on German roads involved in crashes including the influence of helmets on injury severity. The study is based on documented accidents by the German In-Depth Accident Study (GIDAS). GIDAS data gathering initiated in 1999.
2012 – “Injury Pattern, Injury Severity, and Mortality in 33,495 Hospital-admitted Victims of Motorized Two-wheeled Vehicle Crashes in The Netherlands”
Data from the Institute for Road Safety Research and the Hospital Trauma Databases were analyzed. Injury Severity Score and Abbreviated Injury Scale to calculate the relative risks of severe trauma and mortality.
While lower-extremity injuries most commonly occur in all motorcycle crashes, head injuries are most frequent in fatal crashes. Helmets and helmet use laws have been shown to be effective in reducing head injuries and deaths from motorcycle crashes. Alcohol is the major contributing factor to fatal crashes. Enforcement of legal limits on the blood alcohol concentration is effective in reducing motorcycle deaths, while some alcohol-related interventions such as a minimal legal drinking age, increased alcohol excise taxes, and responsible beverage service specifically for motorcycle riders have not been examined. Other modifiable protective or risk factors comprise inexperience and driver training, conspicuity and daytime headlight laws, motorcycle licensure and ownership, riding speed, and risk-taking behaviors.
2009 – “Crash Characteristics and Patterns of Injury Among Hospitalized Motorised Two-wheeled Vehicle Users in Urban India”
This is a report on the crash characteristics and injury patterns among a cohort of MTV riders and pillions presenting to hospital post-crash.
This study aims to define the characteristics of lower-extremity injuries among motorcyclists involved in traffic crashes. The results of this study provide information on the cost of different types of lower-extremity injuries and long-term disabilities that might result from these types of injuries.
2008 – “An Analysis of Hospitalized Motorcyclists in the State of Maryland Based on Helmet Use and Outcome”
Data on injured motorcyclists is captured from the trauma registry, hospital discharge records, autopsy reports, and through a linkage with police crash reports. Injured parties are assessed six-months and one-year post crash. By analyzing riders who were injured, this project has shown that the likelihood of sustaining a brain injury increases when wearing a non-compliant helmet.
2006 – “Injury Patterns and Severity Among Hospitalized Motorcyclists: A Comparison of Younger and Older Riders”
The purpose of this analysis was to determine differences, if any, in injury patterns to older vs. younger motorcyclists and to explore rider, vehicle, and environmental factors associated with these differences.
Abstract. Of the 1239 patients requiring hospital admission, 74 died. The probability of reduced survival was estimated by a logistic regression model using independent variables such as head injury, thoracic trauma, abdominal injury, spinal injury and pelvic fracture and a compound variable of pelvic fracture combined with a long bone fracture.