Motorcycles are considerably more complex to operate than cars, and riders are significantly more vulnerable to potentially devastating injuries. Motorcycle crashes may be caused by a number of factors, including rider error or inexperience, excessive speed, other driver distraction, carelessness or inattention, roadway or mechanical defects, and weather related hazards. For these reasons, a motorcycle crash expert is critically important in a motorcycle crash case.
Dr. Lloyd’s interest in motorcycling began at the age of 13, when he built his first motorcycle and learned to ride. Since that time he has amassed many years of technical expertise. In addition to holding a PhD in Ergonomics (Human Factors), with a specialization in Biomechanics, John holds several certifications in motorcycle accident reconstruction.
Based on his 38+ years of riding and advanced training as a motorcyclist, he is one of a few experts who have been admitted in court to testify regarding motorcycle handling and operation.
Using his FAA part 109 pilot’s license, Dr. Lloyd can fly drones to generate 3D forensic maps of crash scenes for reconstruction purposes. Based on his PhD in human factors / ergonomics, John is qualified to address human factors issues including line of sight analysis, perception response time (PRT), distracted driving and impairment. Given his extensive experience as a senior researcher in biomechanics, with a specialization in head and brain injury biomechanics, including research and development of helmets, Dr. Lloyd is also uniquely qualified to opine on injury biomechanics and motorcycle helmet protection issues.
Links to several of Dr. Lloyd’s articles pertaining to motorcycle accident reconstruction and biomechanical evaluation of motorcycle helmets are presented below:
A solo motorcycle crash is one of the leading causes of motorcycle accidents. These accidents are unique in that, typically, no other vehicles are involved. Oftentimes the root cause is rider error due to the fact that motorcycles are considerable more complex to operate than passenger vehicles. Discover how to avoid solo motorcycle crashes with valuable insights from a motorcycle expert.
Riders involved in a solo motorcycle crash typically fit one of two categories:
Riding too fast
Inadequate experience
The first category speaks for itself. Riding too fast for conditions reduces time and distance available to respond safely to potential hazards, such as other roadway users.
Lack of experience includes lack of appropriate training or failure to maintain training. Many riders purchase an expensive motorcycle – far too powerful and heavy for their riding abilities – and ride less than 3000 miles per year – generally in a straight line. When they are faced with a hazard, they panic and make poor choices, all too often resulting in injury or death.
Motorcycle Braking
Unlike cars, the front and rear brake systems on a motorcycle are typically independent — the front brake is operated by a lever on the right side of the handlebar, while the rear brake is operated by a foot pedal, also on the right side. As car drivers we learn that hard braking is performed by the right foot. However, doing so on a motorcycle will inevitably lead to trouble. In fact, about 70 percent of the braking power on a motorcycle comes from the front brake lever.
As front brake force increases weight transfers to the front tire, increasing the tire force acting on the road surface, which permits application of even greater front brake force.
However, sudden over-braking on the front, on a motorcycle not equipped with ABS, can produce a front-tire skid, which can cause loss of control in under one second. So, for an inexperienced rider it can be challenging to find the ‘sweet-spot’ between hard braking and over-braking on the front tire.
Whereas, utilization of the rear brake without the front brake produces only 30% braking efficiency and can cause the rear end of the motorcycle to skid and ‘fishtail’, due to the fact that there is generally less weight and a larger contact area (less pressure) on the rear tire.
Experienced motorcyclists learn to use both the front and rear brakes in unison and, together both brakes can out-perform the stopping power of most other roadway vehicles.
Motorcycle Steering
Motorcycles also differ from other vehicles in the way that they steer. In a car if you want to go right you turn the steering wheel to the right and visa versa. Whereas, on a motorcycle if you want to go right you turn the handlebar to the left. On the surface this appears to be counter-intuitive. However, due to the geometry of motorcycles, when you turn the handlebar in one direction, the bike will lean in the opposite direction. It is this lean that causes the motorcycle to turn. This phenomenon is called counter-steering.
To turn a tighter curve you simply increase the lean angle. Modern sport motorcycles are capable of lean angles up to 60 degrees, allowing motorcycle racers to turn corners at high speeds. However, most curves on public roads don’t require more than 15 degree lean angle, which is generally the comfort limit of many novice riders.
The number one cause of motorcycle crashes involving other vehicles is a left-turning driver across the rider’s path. In every case, the intruding motorist explains that they “did not see the approaching motorcycle”. The motorcycle was not conspicuous.
Expectancy
How can a motorist fail to see something as large as a modern motorcycle? The answer – expectancy. According to the National Highway Transportation Safety Authority (NHTSA), motorcycles account for only 0.6% of total vehicle miles traveled in the United States. Thus, motorists have more than a 99% expectancy that the next vehicle they see will NOT be a motorcycle. Through experiential learning drivers have learned to look for other automobiles, not motorcycles.
It is not that a motorist does not see the motorcycle. However, it does not meet their expectation and therefore they may fail to identify the approaching motorcycle.
What can motorcyclists do to reduce their risk of collision when a driver causes a path obstruction at an intersection? According to human factors research, roadway users respond to hazards based on available information. They fail to respond when the available information is insufficient. Based on my experience as a motorcycle rider and human factor expert, conspicuity is key to increasing the information available to motorists. As motorcyclists we need to take responsibility to make our presence known to other roadway users.
Many opportunities to improve conspicuity are available, which generally fall into two categories – audible and visual. Many riders are familiar with the concept “Loud pipes save lives”, as often declared on stickers affixed to their helmets. However, since noise intensity decreases as a function of the distance-squared, loud pipes are only effective in close proximity. Moreover, the greater volume is actually behind the motorcycle, not in front.
Human Factors research teaches that to improve driver detection and therefore avoidance of motorcycles on the road, we can enhance our visual conspicuity by following a few simple guidelines. These are captured by the acronym CAPLETS, which includes Contrast, Anticipation, Pattern, Lighting, Eccentricity, Time of Exposure, and Size.
Conspicuous Contrast
Contrast addresses the ability of a motorcycle and rider to stand out from their environment. For example, a black motorcycle on an asphalt surface is more difficult to distinguish than a yellow or red bike, especially under nighttime conditions. The same is true for the rider. Dark clothing makes it more difficult for a motorcyclist to be detected on the roadway. Brighter colors, especially high-vis yellow or orange, are more likely to create a greater contrast and therefore be more recognizable.
Anticipation Conspicuity
Anticipation refers to the expectation of a given event. When motorcyclists ride together in a group, motorists are more likely to expect and therefore look for additional motorcycles. For this reason, a group riding together is often safer than a solo motorcyclist traveling alone.
Conspicuous Patterns
Patterns aid recognition by relying on one’s past experiences. Obviously, most motorists are familiar with the shape or pattern of a motorcycle and can easily distinguish one during daytime conditions. However, at night the pattern exhibited by a single headlight, may not aid a driver in identifying an approaching motorcycle. Motorcycles equipped with additional lighting that outlines its shape are more likely to be recognized on the roadway and hence less likely that their path will be intruded by a motorist.
Conspicuous Lighting
The purpose of Lighting is somewhat self-explanatory. More lighting means more information for other roadway users. Lighting is beneficial not just at night, but also during the day. The photograph, below, of one of my motorcycles illustrates how effective additional lighting is in providing information necessary to motorists to recognize my presence on a motorcycle. Headlight modulators can also increase conspicuity by switching between low and high beam automatically at a rate of approximately 4 times per second. The modulators are equipped with a light sensor, which turns off this feature at night. I have personally installed headlight modulators on several of my bikes and can attest as to their effectiveness.
Eccentricity
Eccentricity relates to the viewing angle. When a motorcycle is approaching an intersection, the viewing angle of the rider to an automobile on the right, waiting to make a left turn across the roadway is close to zero. Whereas, for the driver at the road junction, their viewing angle, unless properly turning their head to look for oncoming vehicles, is close to 90 degrees. There is not much that a rider can do to improve the motorists viewing angle. However, I have found that, when approaching an intersection at which a driver is waiting to make a turn across my path, by moving my motorcycle side to side within my lane helps to catch their attention.
Time of Exposure
Time of Exposure. It is critically important at intersections to ensure that no visual obstructions exist between the rider and motorist that could limit time available to detect your presence. If fixed obstructions, such as trees or signage, are present I will position my motorcycle in a manner that provides a clear line of sight. Whereas, if a vehicle in front of or to the right of my motorcycle may pose a potential visual obstruction at an approaching intersection, I will move forward, or drop back, allowing a clear 3-second window between myself and other vehicles, thereby affording a waiting motorist every opportunity to detect and identify me on the road. Speed can also negatively affect time of exposure. At greater speeds other drivers have less available time to detect a motorcyclists presence. For this reason, I advise that it is best to travel at or within 5 mph of the posted speed limit.
Conspicuous Size
Size matters, when it comes to conspicuity. Remember that motorists are looking for other automobiles. Larger motorcycles tend to be identified more quickly than smaller bikes, or bicycles. An opportunity may exist to make your motorcycle appear larger than reality through the use of additional lighting, such as led lights mounted on left and right side mirrors, and/or by the front wheel axle.
Please call Dr. Lloyd at 813-624-8986 or email DrJohnLloyd@Tampabay.RR.com to discuss how he can be of help to you with your case.
To consider whether a motorcycle helmet might reduce the risk of brain trauma in a motorcycle accident it is first important to understand the two primary mechanisms associated with traumatic brain injury – impact loading and impulse loading, according to motorcycle helmet expert, Dr. John Lloyd.
Impact loading involves a direct blow transmitted primarily through the center of mass of the head, resulting in extracranial focal injuries, such as contusions, lacerations and external hematomas, as well as skull fractures. Shock waves from blunt force trauma may also cause underlying focal brain injuries, such as cerebral contusions, subarachnoid hematomas and intracerebral hemorrhages.
Whereas, impulse or inertial loading caused by sudden movement of the brain relative to the skull, produces cerebral concussion. Inertial loading at the surface of the brain can cause subdural hemorrhage due to bridging vein rupture, whereas if affecting the neural structures deeper within the brain can produce diffuse axonal injury (DAI).
Epidemiology Studies
Two major epidemiologic studies into the causation of motorcycle accidents have been conducted in North America and Europe: the Hurt Report and the MAIDS report. The Hurt Report showed that failure of motorists to detect and recognize motorcycles in traffic is the predominating cause of motorcycle accidents. Seventy-five percent of accidents were found to involve a motorcycle and a passenger vehicle, while the remaining 25% of accidents were single motorcycle accidents. Two-thirds of motorcycle-car crashes occurred when the car driver failed to see the approaching motorcycle and violated the rider’s right-of-way. Findings indicate that severity of injury increases with speed, alcohol motorcycle size and speed.
The MAIDS study (Motorcycle Accidents In Depth Study) is the most recent epidemiologic study of accidents involving motorcycles, scooters and mopeds, which was conducted in 1999 to investigate motorcycle accident exposure data across five European countries. Key findings show that passenger cars were the most frequent collision partner (60%), where 69% of the drivers report that they did not see the motorcycle and the predominance of motorcycle accidents (54.3%) occurred at an intersection.
In 1995, the European Commission Directorate General for Energy and Transport initiated a Cooperative Scientific and Technical Research (COST) program to investigate Motorcycle Safety Helmets. Several agencies from Finland, the United Kingdom, France and Germany participated in this study, which compiled and analyzed data from 4,700 motorcycle fatalities in Europe, each year. The COST report documents that 75% of all fatal motorcycle accidents involve head injury. Linear forces were present in only 31% of fatal head injuries, while rotational forces were found to be the primary cause in over 60% of cases. Within the scope of this study experiments were performed using drop tests with accelerometers to measure linear and rotational accelerations of the brain and skull mass associated with different types of impacts. These tests confirmed rotational acceleration to be a primary cause of brain injury in helmeted motorcycle accidents.
While the motorcycle helmet is currently the most effective means of protection for riders, data suggests that motorcycle helmets are only 37-42% effective in preventing fatal injury. By reducing the effects of blunt trauma to the head it is generally believed that risk of brain injury, including concussion, axonal injury and hematoma would also be reduced. However, the mechanisms of head and brain injury are very different. New research shows that these mechanisms are poorly coupled, contrary to previous beliefs.
Summary
Motorcycle helmet expert report that rotational forces acting on the brain are the underlying cause of traumatic brain injuries.
Motorcycle helmets, including those certified under DOT and SNELL standards are designed to mitigate forces associated with linear acceleration.
According to motorcycle helmet expert, helmets are not currently certified under either DOT or SNELL standard against their ability to protect against the angular / rotational forces.
Epidemiologic evidence from the COST-327 report indicates that motorcycle helmets do not provide adequate protection against closed head and brain injuries
New Research
Motorcycle helmet expert Dr. John Lloyd recently published a new study: Biomechanics of Motorcycle Helmets: Protection Against Head and Brain Injury. Testing proves that motorcycle helmets provide inadequate protection against concussion and severe traumatic brain injury associated with even relatively minor head impact
In 2016 there were more than 8.4 million motorcycles registered in the United States, representing 3.2% of all US vehicles. California, Florida and Texas were the leading States in terms of the motorcycle popularity; collectively representing 22% of all US registered motorcycles. According to the U.S. National Highway Traffic Safety Administration (NHTSA), when compared per vehicle mile traveled with automobiles, due to their vulnerability, motorcyclists’ risk of a fatal crash is 30-35 times greater than that of a car occupant.
Number One Cause of Motorcycle Crashes
Seventy-five percent of accidents were found to involve a motorcycle and a passenger vehicle, while the remaining 25% of accidents were single motorcycle accidents.
The number one cause of motorcycle crashes is a motorist making a left turn across motorcycle path. With reference to the Hurt report in the United States and the MAIDS in-depth investigation of motorcycle accidents in Europe, approximately two-thirds of all motorcycle crashes involving other vehicles are caused due to violation of the motorcycle rider’s right of way by the failure of motorists to detect and recognize motorcycles on the road.
While the motorcycle rider has right of way, they are also more vulnerable to injury. Motorcyclists must therefore be extra-vigilant, especially when approaching intersections. Appropriate riding gear, including a DOT certified helmet, motorcycle jacket and riding boots offer the motorcyclist the best protection. Findings of the Hurt study indicate that severity of motorcyclist injury increases with speed, alcohol consumption, motorcycle size and speed.
Motorcyclist Conspicuity
Conspicuity is one of the key factors in motorcycle road crashes around the world. The inability and difficulty of other road users in detecting motorcycles either at day or at night has contributed to conspicuity related motorcycle crashes. Additional lights and brightly colored riding gear can help to improve motorcyclists conspicuity to other roadway users. The following image depicts this author wearing a hi-visibility motorcycle jacket and helmet to enhance conspicuity.
Please call Dr. Lloyd at 813-624-8986 or email DrJohnLloyd@Tampabay.RR.com to discuss how he can be of help to you with your case.
Motorcycles are a luxury in the developed world, where they are used mostly for recreation. Whereas in developing countries, motorcycles are required for utilitarian purposes due to lower prices and greater fuel economy. It is estimated that in 2016 there will be more than 134 million motorcycles worldwide, 60-80% of which are in the Asia Pacific and Southern and Eastern Asia regions. In 2011 there were more than 8.2 million registered motorcycles in the United States, representing 3% of all US registered vehicles, with California, Florida and Texas leading the number of motorcycles per state.
In the United States motorcyclists travelled 18.5 billion miles in 2011, which represents only 0.6% of total vehicle miles travelled, yet motorcyclists accounted for 14% (4,612) of traffic fatalities and 4% (81,000) of all occupant injuries 2. According to the U.S. National Highway Traffic Safety Administration (NHTSA), when compared with automobiles, per vehicle mile traveled, motorcyclists’ risk of a fatal crash is 35 times greater than that of a car occupant
In a motorcycle accident, the motorcycle and rider typically become independent, each following their own path to final rest. Consequently, the biomechanical analysis of a motorcycle accident is complex. A biomechanical model to assess rider kinematics associated with motorcycle accidents is presented, which may be important to forensic scientists involved in the analysis of such events. This model can also be applied to other activities, including cycling, equestrian sports, skiing, skating, running, etc.
It is first important to understand the mechanisms by which a rider may be ejected from their motorcycle and how drag factors affect the motorcycle and rider independently. Next we determine rider trajectory, taking into consideration rider anthropometry and posture, results from which are used to derive impact velocity as a function of linear and angular components. A case study is presented, demonstrating how the presented model can be applied to a collision involving a single motorcycle.
Impact loading involves a direct blow transmitted primarily through the center of mass of the head, resulting in extracranial focal injuries, such as contusions, lacerations and external hematomas, as well as skull fractures. Shock waves from blunt force trauma may also cause underlying focal brain injuries, such as cerebral contusions, subarachnoid hematomas and intracerebral hemorrhages.
