Crashes involving motorcycles are unique due to the manner in which they respond to different roadway hazards. Motorcycle inspection and testing may be a necessary component of a motorcycle crash analysis. Dr. John Lloyd has extensive expertise in motorcycle inspection and testing.

Exemplar motorcycles are typically rented and outfitted with instrumentation to measure acceleration, braking efficiency, lean angle, as well as GPS tracking and multiple GoPro cameras. Dr. Lloyd will ride through the crash scene on the instrumented motorcycle to document the rider’s view along with the motorcycle handling characteristics. A drone may also be used to capture an aerial view. This information has proven to be invaluable in the analysis of motorcycle crash cases.

motorcycle test - GoPro — GoPro camera view

motorcycle test - ESR data — GoPro camera view

One particular motorcycle crash case involved loss of control due to a pothole in the road. The motorcycle fell on the rider, resulting in near amputation of his right foot. A thorough description of Dr. Lloyd’s comprehensive motorcycle inspection and testing in that case can be found here.

Unfortunately, many motorists do not recognize motorcycles on the road, resulting in the number one cause of motorcycle crashes.

The image alongside depicts a near-collision in which a driver made a sudden and unexpected left turn across the path of a motorcycle that was being tested by Dr. Lloyd. Appropriate braking operation by the rider and braking performance by the motorcycle is required to avoid collision.

Motorcycle accident analysis often requires a teardown and careful inspection of the bike to investigate for possible contributing factors. Dr. Lloyd has decades of experience with motorcycle mechanics. A thorough evaluation includes inspection of tires, brakes, suspension setup, electrical components as well as any aftermarket parts. Inspections are best performed at Dr. Lloyd’s laboratory, but can also be conducted in the field.

The following image is from an inspection of the front brake system on a Suzuki GSXR, which was the subject of a manufacturer recall

In a nighttime collision involving a scooter, it was claimed by the driver of a left turning vehicle that the scooter headlights were not operational. A thorough inspection of the electrical system was required by a motorcycle inspection expert:

Dr. Lloyd has also participated in motorcycle build-off competitions and won a trophy for his custom Kawasaki Vulcan motorcycle.

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.

Motorcycle Accident Expert

Motorcycle collision analysis is a highly specialized discipline in which Dr. Lloyd is eminently qualified as a motorcycle accident expert. In addition to holding a PhD in Ergonomics (Human Factors), with a specialization in Biomechanics, John has more that 20 years and 200,000 miles of experience riding motorcycles. Dr. Lloyd has completed numerous advanced programs, including Motorcycle Safety Foundation (MSF), Experienced Rider Course and Total Rider Tech Advanced training.

Motorcycle Helmets and Brain Injury

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.

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).

Holbourn was the first to cite angular / rotational acceleration as an important mechanism in brain injury. Gennarelli, Thibault, and colleagues, in a series of studies using live primates and physical models investigated the role of rotational acceleration in brain injury. They concluded that angular acceleration contributes more than linear acceleration to brain injuries, including concussion, axonal injury, and subdural hematoma.

Motorcycle Helmet Testing

Traditional testing of motorcycle helmets focuses on reducing the effect of linear impact forces by dropping them from a given height onto an anvil and measuring the resultant peak linear acceleration. According to the Federal Motor Vehicle Safety Standard (FMVSS) 218, commonly known as the DOT helmet standard, the test involves dropping a motorcycle helmet onto a flat steel and hemispherical anvil at an impact velocity of 6.0 m/s (13.4mph). In general, if peak linear acceleration is less than 400g, the helmet is considered acceptable. Current motorcycle helmet testing standards do not incorporate measures of angular acceleration and therefore do not address whether any helmets can provide adequate protection against catastrophic brain injuries, such as concussion, axonal injury and subdural hematoma.

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.

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.
Motorcycle 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

Human Factors of Motorcycle Accidents

Human factors in vehicle collisions include all factors related to drivers and other road users that may contribute to a collision. Examples include driver behavior, visual and auditory acuity, decision-making ability, and reaction speed. A 1985 report based on British and American crash data found driver error, intoxication and other human factors contribute wholly or partly to about 93% of crashes.

Motorcycle Inspection

Motorcycle accident analysis often requires involves a teardown and careful inspection of the machine to investigate for possible contributing factors. Our engineers have a combined 70 years experience with motorcycle mechanics.

A thorough evaluation includes inspection of tires, brakes, suspension setup, electrical components as well as any aftermarket parts.

Dr. John Lloyd | Motorcycle Crash, Biomechanics, Human Factors Expert

813-624-8986 | John@DrBiomechanics.com

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Motorcycle Inspection and Testing

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Motorcycle Helmets and Brain Injury

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Human Factors of Motorcycle Accidents

Motorcycle Inspection