Motorcycle accident investigation Dr. John Lloyd has served attorneys nationwide for 25+ years in biomechanics, human factors, helmet testing and motorcycle accident expert
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.
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.
Dr. John Lloyd has over 25 years of forensic consulting experience as a motorcycle accident expert including motorcycle handling and operation as well as maintenance, repair and motorcycle inspection.
Analyzing a crash scene may be somewhat complex, but can be critical to understanding the nature of the collision. Some of the questions I, as an experienced motorcyclist, consider when performing a crash scene inspection include: What was the general condition of the roadway at the time of the crash? Are there any hazards, such as potholes, gouges, debris, uneven lanes, tar snakes, cattle grids, etc., that could have affected the stability of a motorcycle? Did the topography of the roadway cause or contribute to the collision? Did fluid residue on the road surface affect braking efficiency? Were there any unexpected hazards, such as a hidden driveway? Did roadway design play a factor, such as traffic signals on a curve or below the crest of a hill? Many of these questions, and more, are best addressed through an in-person crash scene inspection.
tar snakesroadway gougespotholescattle grid
Coefficient of Friction, or drag factor, of the roadway at the scene of the crash is an important measurement, but one that is rarely completed by law enforcement traffic investigators. Fluids, such as engine and transmission oils from poorly maintained vehicles, often accumulate at or near intersections, especially those with traffic signals. This residue can reduce motorcycle braking efficiency by 50 percent, or more, especially when wet. The Drag Factor can be easily measured using a simple, but effective tool, known as a Braker Box.
Dr. Lloyd, has obtained his FAA part 109 unmanned aircraft systems pilot license. As part of his crash scene inspection he will fly a drone to capture aerial images and videos at the crash scene. Sometimes, if the crash scene is in the vicinity of an airport, special authorization may be required from the FAA.
By flying a grid mission, as illustrated below, an array of aerial images are captured. A ‘point cloud’ is created using specialized photogrammetry software, to produce a high resolution 3D model of the crash scene.
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 highly sensitive to changes in roadway conditions. Potholes can destabilize a motorcycle, causing the rider to lose control. The following is a case in which a rider claimed he was traveling at only 15 miles per hour, when he came upon a large pothole in the roadway and lost control. The motorcycle fell to the right, with the right foot peg penetrating the rider’s leg, leading to a near amputation of his right foot. Dr. Lloyd was retained to investigate the cause of the motorcycle pothole crash.
Test Instrumentation
An exemplar Honda CBR 929RR motorcycle was acquired and instrumented with accelerometers installed on the front axle, rear axle and handlebars:
Data acquisition was controlled using a National Instruments cDAQ 9178 and acquired at 10 kHz per channel on a Windows tablet running LabVIEW software:
Pothole Crash Testing
Using the instrumented motorcycle, Dr. Lloyd constructed an exemplar pothole in an open parking lot using ramps to investigate how the length and depth of the pothole affected stability of the motorcycle. In addition to sensors, testing was recorded using high speed and standard video, as well as GoPro cameras mounted on the motorcycle
Results
Based on analyses and physical evidence, that the speed of the motorcycle while crossing the roadway defect was likely 14 -18 miles per hour. At such speeds, the front and rear suspensions have a tendency to approach maximum compression. along with substantial deformation of the tires.
Conclusions
Dr. Lloyd determined that the motorcycle crash was caused due to the motorcycle accelerating as it crossed the pothole. When the rear wheel crossed the fore edge of the defect it lost contact with the roadway and the rear wheel speed increased without resistance. Upon contact with the aft edge of the roadway defect the rear wheel was at a higher rate of speed than the rest of the motorcycle, causing the motorcycle to unexpectedly wheelie.
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.
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.
