Category Archives: helmet expert

Helmet expert Dr. John Lloyd has served attorneys nationwide for 25+ years in biomechanics, human factors, helmet testing and motorcycle accident expert

Helmet Expert Vital in Motorcycle Accident Cases

Why Is a Helmet Expert Vital in Motorcycle Accident Cases?

Motorcycle accidents usually cause severe injuries, especially head injuries and brain injuries. Hence, helmet analysis is a key factor in a legal suit. The motorcycle helmet expert assesses how helmets perform in reducing head injuries and brain injuries as well as liability ascertainment in cases of accidents. 

Dr. John Lloyd is among the top experts in the field, known extensively as an expert in motorcycle accident biomechanics and human factors. Dr. Lloyd has testified all over the United States during the last 30 years and performs scientific analyses of helmets concerning safety and accident reconstructions.

Motorcycle Helmet Expert in Accident Cases

Importance of Motorcycle Helmet Expert in Accident Cases

A motorcycle helmet expert evaluates the performance of the helmet during the crash: whether or not it meets regulatory safety standards and state of the science. Assessing helmet design, integrity of the material, and impact absorption, one of the experts, Dr. John Lloyd, evaluates the the helmet effectiveness for its intended function of protecting the rider from injuries.

Evaluation of the Damage Sustained by the Helmet and the Forces of Impact

Many of the functions of the helmet expert witness include examining the helmet after a collision for damage. For example:

  • Cracks, dents, and abrasions, which inform how the helmet interacted during the crash
  • Impact locations as a measure of severity of head trauma.
  • Compression of helmet liner analyses for insights into force absorption.

Determining Compliance with Regulatory Safety Standards

Helmets should also be manufactured to meet the safety regulations for DOT (Department of Transportation), ECE, and Snell standards. A motorcycle helmet expert will review the facts and determine whether the specific helmet met such safety requirements and standards. 

Investigating Helmet Fit and Proper Usage

If a helmet does not fit well, it loses some of its protective functionality and can further enhance the risk of a serious head or brain injury. The motorcycle helmet expert examines: 

  • Was the rider wearing the right size helmet?
  • Was the helmet secured and fastened?
  • Did improper fit contribute to the severity of rider injuries?

Dr. Lloyd’s expertise assists legal teams in determining whether the helmet was misused or defective. 

Testifying On the Stand

In litigation, the motorcycle crash expert presents scientific results to support claims regarding injury causation and helmet performance. Dr. Lloyd has testified in Federal, Superior, District, and Circuit courts more than 60 times. His testimony can enlighten judges and juries on the issues at stake regarding the use and abuse of helmets.  can enlighten judges and juries on the issues at stake regarding the use and abuse of helmets. 

Was the rider wearing the right size of helmet

Can a motorcycle helmet expert determine if a defective helmet caused injuries?

Yes. A motorcycle helmet expert can identify defects in design and manufacture, improper materials, and design flaws that contributed to injuries. 

  1. How does helmet analysis help in accident reconstruction?

Helmet analysis yields crucial data concerning impact force, injury pattern, and crash dynamics, assisting experts such as Dr. John Lloyd in reconstructing the motorcycle accident from a scientific viewpoint. s yields crucial data concerning impact force, injury pattern, and crash dynamics assisting experts such as Dr. John Lloyd in reconstructing the accident from a scientific viewpoint. 

Final Thoughts! 

The motorcycle helmet expert is a significant element in any accident investigation, conducting helmet analysis regarding damage, impact, and fit. Through scientific analysis and expert testimony, Dr. John Lloyd helps to improve motorcycle safety and the settlement of accidents.

Expert in Motorcycle Accidents, Biomechanics & Human Factors

 John Lloyd, PhD, CPE, ACTAR has served as an expert witness for more than 30 years, providing nationwide expert testimony in motorcycle accident reconstructionmotorcycle riding and operationhuman factorsbiomechanics, and helmet protection

Dr. Lloyd’s expertise in motorcycle accident reconstruction, biomechanics, and human factors has been accepted by courts in numerous jurisdictions to provide analyses involving:

Unrivaled Expertise

Dr. Lloyd is a distinguished authority in motorcycle accident reconstruction and human factors analysis, with decades of experience. His understanding of the unique dynamics involved in motorcycle crashes sets him apart as a true specialist in the field.

John earned a Ph.D. in Ergonomics / Human Factors with a specialization in biomechanics from Loughborough University in England in 2002 and is Board Certified through the Board of Certification in Professional Ergonomics. He has has also attained Accreditation as a Traffic Accident Reconstructionist (ACTAR # 4658), with speciality certifications in motorcycle and motor vehicle accident reconstruction, as well as human factors.

Dr. Lloyd spent his career as a senior researcher at the VA Hospital in Tampa, FL, serving as Director of the Biomechanics Research Laboratory and Director of the Traumatic Brain Injury Research Laboratory. In addition he held a courtesy faculty appointment as Assistant Professor in the University of South Florida College of Engineering from 2002-2022, and is currently the Research Director of BRAINS, Inc.

To date, Dr. Lloyd’s work has been published in six book chapters and 33 peer-reviewed journals, as well as  presented at more than 100 national and international conferences (see curriculum vitae).

Comprehensive Approach

Dr. Lloyd goes beyond the obvious and delves deep into the technical intricacies of each case. As a multi-disciplinary expert he combines, accident reconstruction, biomechanics and human factors to provide a holistic view of the accident, ensuring no detail goes unanalyzed.

Accurate Motorcycle Crash Reconstructions

Using state-of-the-science reconstruction tools and real world data, Dr. Lloyd meticulously creates 3D accident reconstructions with unparalleled accuracy. This empowers him to provide precise insights into the sequence of events leading up to the incident.

Human Factors Insight

Understanding the role of human behavior is crucial in accident analysis. Dr. Lloyd’s human factors expertise allows him to investigate the cognitive factors affecting both motorcycle riders and automobile drivers, offering invaluable insights into decision-making processes.

Courtroom Excellence

Dr. Lloyd’s reputation as a credible and authoritative expert makes him an invaluable asset in the courtroom. He excels at conveying complex technical information to the jury in an accessible manner, helping you present a compelling case, backed by robust scientific analysis.

To date, Dr. Lloyd has provided expert witness Deposition and Trial Testimony in more than 160 civil and criminal cases. His expertise in motorcycle crashes, motorcycle riding and operation, helmet protection, biomechanics and human factors has been recognized by courts across the United States and Internationally. The analysis methods that Dr. Lloyd utilizes are published in peer-reviewed scientific journals.

Unquestionable Expert Integrity

Ethics and integrity are the cornerstones of our practice. You can trust that our analyses are unbiased, objective and founded on the highest standards of professionalism.

Contact

Please call Dr. Lloyd at 813-624-8986 or email John@DrBiomechanics.com to discuss how he can be of help to you with your case.

Alabama     Alaska     Arizona     Arkansas     California     Colorado     Connecticut     Delaware     Florida     Georgia     Hawaii     Idaho     Illinois     Indiana     Iowa     Kansas     Kentucky     Louisiana     Maine     Maryland     Massachusetts     Michigan     Minnesota     Mississippi     Missouri     Montana     Nebraska     Nevada     New Hampshire     New Jersey     New Mexico     New York     North Carolina     North Dakota     Ohio     Oklahoma     Oregon     Pennsylvania     Puerto Rico     Rhode Island     South Carolina     South Dakota     Tennessee     Texas     Utah     Vermont     Virginia     Washington     West Virginia     Wisconsin     Wyoming

Research article “Brain Injury in Sports” published in Journal of Neurosurgery

Dr. Lloyd is pleased to announce that his research article  on Sports Brain Injury, co-authored with Dr. Frank Conidi has been published in the Journal of Neurosurgery:

Lloyd - Sports Brain Injury

OBJECT
Helmets are used for sports, military, and transportation to protect against impact forces and associated injuries. The common belief among end users is that the helmet protects the whole head, including the sports brain injury. However, current consensus among biomechanists and sports neurologists indicates that helmets do not provide significant protection against concussion and sport brain injury. In this paper the authors present existing scientific evidence on the mechanisms underlying traumatic head and sports brain injury, along with a biomechanical evaluation of 21 current and retired football helmets.

METHODS
The National Operating Committee on Standards for Athletic Equipment (NOCSAE) standard test apparatus was modified and validated for impact testing of protective headwear to include the measurement of both linear and angular kinematics. From a drop height of 2.0 m onto a flat steel anvil, each football helmet was impacted 5 times in the occipital area.

RESULTS
Skull fracture risk was determined for each of the current varsity football helmets by calculating the percentage reduction in linear acceleration relative to a 140-g skull fracture threshold. Risk of subdural hematoma was determined by calculating the percentage reduction in angular acceleration relative to the bridging vein failure threshold, computed as a function of impact duration. Ranking the helmets according to their performance under these criteria, the authors determined that the Schutt Vengeance performed the best overall.

CONCLUSIONS
The study findings demonstrated that not all football helmets provide equal or adequate protection against either focal head injuries or traumatic brain injuries. In fact, some of the most popular helmets on the field ranked among the worst. While protection is improving, none of the current or retired varsity football helmets can provide absolute protection against brain injuries, including concussions and subdural hematomas. To maximize protection against head and brain injuries for football players of all ages, the authors propose thresholds for all sports helmets based on a peak linear acceleration no greater than 90 g and a peak angular acceleration not exceeding 1700 rad/sec2.

http://thejns.org/doi/abs/10.3171/2014.11.JNS141742

Helmets Do Not Prevent Brain Injury?

In a word. No.

A better question might be “Can Helmets Prevent Brain Injury?” Same answer – No.

It is not currently possible to develop a helmet that can protect all persons under all foreseen and unforeseen circumstances. But, given current medical understanding of head and brain injuries as well as 21st Century advanced materials, it is certainly possible to protect most people from life-threattening brain injuries under foreseen circumstances.

Helmets are actually intended to protect against blunt trauma injuries to the head. They are not specifically designed to prevent brain injuries.

The mechanisms which cause head and brain injuries are quite different. Forces associated with linear accelerations are responsible for visible injuries, such as lacerations, contusions and skull fracture. Whereas, brain injuries, including concussions, axonal injury and subdural hematoma are caused by forces associated with angular / rotational accelerations. When the head impacts a surface, the skull may come to an abrupt stop, but inertia acting on the brain will cause it to continue to move This inertia strains the nerves and blood vessels of the brain, causing injuries. The type of injury is dependent on the magnitude of this strain and the time duration over which it acts on the brain.

Helmets may indeed reduce the rotational forces acting on the brain. But since helmets are not currently certified according to their ability to protect against brain injury the level of protection is not standardized. Hence, it is possible to sustain catastrophic brain injuries, even while wearing a helmet.

I have performed extensive biomechanical testing of helmets for various applications, including military, motorcycle, football, skiing / snowboarding and cycling. My testing involves measurement of both linear and angular accelerations, thereby characterizing helmets in terms of their ability to protect against head and brain injuries. Results vary substantially between manufacturers that offer helmets for particular applications and between applications. Based on my testing to date, I can report that certain football helmets seem to outperform helmets in other categories in terms of their ability to protect against head and brain injuries.

Much research has been conducted to understand and quantify biomechanical thresholds for various head and brain injuries, including skull fractures, concussions, axonal injury (damage to nerve fibers in the brain) and subdural hematomas (bleeding in the brain). Why then don’t all helmet manufacturers strive to provide necessary protection?

There are certain intrinsic or personal factors that might increase one’s risk of head and brain injury, but for the rest of us, why do helmets provide inadequate protection against life-threatening head and brain injuries during reasonable or foreseen use?

One example of this is the life-threatening brain injury which former Formula One superstar, Michael Schumaker sustained when he fell while skiing and impacted a rock. It has been reported that Mr. Schumaker was only skiing at about 13mph when he fell and the likelihood of impacting a fixed object while skiing, such as a tree or rock is certainly not unforeseen. So why did his helmet fail to provide necessary protection?

helmet - Dr. John Lloyd

Advanced materials certainly exist to provide required protection for normal persons, including Mr. Schumaker and many other unfortunate victims, under normal or foreseen circumstances. As end-users, we must demand that regulatory organizations require helmet manufacturers meet standards that protect persons who are not otherwise at heightened risk from head and brain injuries due to foreseen circumstances.

NI Week features John Lloyd football helmet expert

Football helmet expert, Dr. John Lloyd,  had the privilege to present his research on football helmets as part of the Keynote address at the National Instrument conference in Austin, TX this week. The audience of 5,000+ attendees learned about Dr. Lloyd’s research into biomechanics of the brain.

It has been said that helmets cannot prevent concussions. I disagree.

As a biomechanist I have dedicated my career to studying the biomechanics of brain injuries. There are two key mechanical forces that give rise to head and brain injuries (1) linear forces, which are responsible for visible injuries, including bruising and skull fractures, and (2) rotational forces, which cause invisible injuries, such as concussion and brain injury.

Since helmets are currently designed to pass testing standards that focus on linear forces only, it is no surprise that helmets have limited benefit in preventing concussions. Through advances in medicine we have learned that concussions can potentially have life-long neurological consequences, including memory impairement and personality changes / behavioral effects.

Over the past years I have developed and validated a testing method to evaluate helmets in terms of their ability to protect against both linear and rotational forces. Using this apparatus I characterized football helmets, results of which have been submitted to Science for publication.

Based on lessons learned from my biomechanical evaluation of various sports helmets, I have devised a matrix of shear-thickening non-Newtonian materials. A prototype helmet was constructed using this matrix liner, results of which show that rotational forces that cause concussion and other brain injuries are reduced by up to 50% compared to a leading football helmet, while also reducing linear forces.sport concussion and sport accident reconstruction expert Dr. John Lloyd

It is my goal and my passion to work with leading helmet companies to make this technology available to players and sports participants of all aged to enhance their protection against brain trauma. I am looking to collaborate with one manufacturer in each sport to offer an exclusive license patent-pending technology.

Testing Proves Motorcycle Helmets Provide Inadequate Protection Against TBI

Motorcycle accident victims account for more than 340,000 fatalities annually, with the United States ranking 8th highest worldwide in the number of motorcycle accident deaths. 75% of all fatal motorcycle accidents involve brain injury, with rotational forces acting on the brain the primary cause of mortality. Current motorcycle helmets are effective at reducing head injuries associated with blunt impact. However, the mechanism of traumatic brain injury is biomechanically very different.

Samples of 9 motorcycle helmet models, representing full-face, three-quarter and shorty designs were evaluated. Helmets, fitted to an instrumented Hybrid III head and neck, were dropped at 13 mph in accordance with DOT motorcycle helmet testing standards.

motorcycle helmet testing

Results show that, on average, there is a 67% risk of concussion and a 10% probability of severe or fatal brain injury associated with a relatively minor 13mph helmeted head impact.

In conclusion, motorcycle helmets provide inadequate protection against concussion and severe traumatic brain injury associated with even relatively minor head impact

New Football Helmet Reduces Brain Injury

John Lloyd of BRAINS, Inc. announced today that football head injuries and concussions can be reduced up to 50 percent with their new helmet safety breakthrough. 

New Helmet Technology Reduces Brain Injuries - football helmet prototype by Dr. John Lloyd | expert

San Antonio, FL – Dr.John Lloyd PhD of BRAINS, Inc. announced their latest breakthrough in football helmet safety today. The unique new helmet technology promises to provide up to 50 percent more protection against football head injuries and concussions. The technology has wide application and can be used in every kind of helmet from baby helmets to military helmets, and for all athletes at risk of concussion and head injuries such as football players, cyclists, skiers, snowboarders, skateboarders, hockey players, baseball players, lacrosse players, boxers, soccer players, equestrian / horse-riding sports, such as polo and horse racing, as well as motorcycle and race car drivers.

Recent medical research documents found that concussions and cumulative head impacts can lead to lifelong neurological consequences such as chronic traumatic encephalopathy, a degenerative brain disease known as CTE and early Alzheimer’s.

The U.S. Centers for Disease Control and Prevention, estimates 1.6 – 3.8 million sport-related brain injuries annually in the United States. Of these 300,000 are attributed to youth football players, some of whom die from their injuries every year – a tragedy difficult for their mothers and families to recover from.

The severity of the issue touching both the nation’s youth and professional athletes has led to thousands of lawsuits and Congressional Hearings. Growing concern has spread to the White House where President Obama recently spoke at the Healthy Kids and Safe Sports Concussion Summit.

The BRAINS, Inc. research team, led by renowned brain injury expert, Dr. John Lloyd, has worked for years on their project to help make sports safer. A controversial subject, some opponents have stated that concussion prevention is impossible. Dedicated to saving lives and preserving brain health, Dr. Lloyd and team persevered with their work leading to this new innovation. “Our results show that forces associated with concussion and brain injury are reduced up to 50% compared to similar testing with a leading football helmet,” said Dr. John Lloyd, Research Director.

“The patent-pending matrix of non-Newtonian materials will not only benefit football, but can be utilized in all sports helmets as well as military, motorcycle and even baby helmets to improve protection and dramatically reduce the risk of brain injuries,” reported Dr. Lloyd.

The materials are inexpensive, and produce a helmet that is considerably lighter and more comfortable than a traditional helmet.   Two additional applications of this new safety technology include medical flooring especially in hospitals and nursing homes or child play areas , as well as vehicle interiors.

About BRAINS, Inc.

BRAINS, Inc. located in San Antonio, Florida, is a research and development company focused on the biomechanics of brain injuries. The company was founded in 2011 by John D. Lloyd Bio, Ph.D., CPE, CBIS, Board Certified Ergonomist and Certified Brain Injury Specialist. He has also provided expert witness services nationwide for over 20 years in the fields of biomechanics, ergonomics and human factors, specializing in the biomechanics of brain injury, including sport and motorcycle helmet cases, slips and falls, motor vehicle accidents and pediatric head trauma. BRAINS, Inc. is open to licensing with manufacturers to bring this much-needed technology to market for the protection of sports participants and athletes of all ages. For additional information visit : http://drbiomechanics.com/sports-helmet-football-helmets/new-helmet-technology/  or call 813-624-8986.

Motorcycle Helmet Standards

Motorcycle helmets were originally developed in the early 20th century and, like most helmets, are modeled after military helmets, the purpose of which is to protect against penetrating head injury. The modern motorcycle helmet, with a hard outer shell and rigid expanded polystyrene (EPS) liner was actually introduced over 60 years ago. The outer shell serves as a second skull, dispersing the impact force over a wider surface area, while the inner shell compresses in an attempt to reduce translational forces. A mechanism to mitigate tangential forces is absent. Since the liner fills the entire inner surface of the shell, tangential forces cannot be absorbed and are transmitted directly to the head and brain. Motorcycle helmet standards focus 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.

Motorcycle Helmet Standards

In motorcycle helmet testing, the risk of impact loading injuries, such as skull fractures, can be determined by measuring linear accelerations experienced by a surrogate head form in response to impact. Whereas risk of impulse or inertial loading injuries, such as concussion, axonal injury and subdural hematoma can be quantified by measuring impact-related angular accelerations at the center of mass of a test head form.

Unfortunately, the evolution of motorcycle helmet design is not driven by advances in scientific knowledge, but rather by the need to meet applicable testing standards. In the United States, standards include the federal motor vehicle safety standard (FMVSS) #218, commonly known as the DOT motorcycle helmet testing standards, and Snell M2015, while ECE 22.05 and BSI 6658 were adopted in European countries. Test procedures involve dropping a helmeted head form onto various steel anvils at impact velocities ranging from only 5.0 to 7.75 m/s (11-17 mph). Pass/fail is based on the ability of the helmet to provide protection against forces associated with linear acceleration in response to impact.

Current motorcycle helmet testing standards do not incorporate measures of angular acceleration and therefore fail to assess whether helmets offer protection against catastrophic brain injuries. The omission of this critical measure is reflected epidemiologically in the disproportion of closed head injuries in fatal motorcycle accidents.

Biomechanical Evaluation of Motorcycle Helmets: Protection Against Head & Brain Injuries

John D. Lloyd, PhD, CPE
Tel: 813-624-8986 | Email: DrJohnLloyd@Tampabay.RR.com

* peer-reviewed and published in the Journal of Forensic Biomechanics, October 2017
** DOWNLOAD PDF FILE

Abstract

Motorcycle accident victims worldwide account for more than 340,000 fatalities annually, with the Unites States ranking 8th highest in number of motorcycle accident deaths, largely due to non-mandatory motorcycle helmet requirements for adults in a number of States. Seventy-five percent of all fatal motorcycle accidents involve head and brain injury, with rotational forces acting on the brain the primary cause of mortality. Current motorcycle helmets are reasonably effective at reducing head injuries associated with blunt impact. However, the mechanism of traumatic brain injury is biomechanically very different from that associated with focal head injury. This study was conducted to evaluate the effectiveness of current motorcycle helmets at reducing the risk of traumatic brain injuries.

Ten motorcycle helmet designs, including full-face, three-quarter and half-helmets were evaluated at an average impact velocity of 8.3 ms-1 (18.5 mph) using a validated test apparatus outfitted with a crash test dummy head and neck. Sensors at the center of mass of the headform enabled high-speed data acquisition of linear and angular head kinematics associated with impact.

Results indicate that none of the standard helmet models tested provide adequate protection against concussion and severe traumatic brain injuries at moderate impact speeds. Only one of the standard motorcycle helmet models tested provided adequate protection against skull fracture.

A new motorcycle helmet prototype, incorporating a liner constructed from a composite matrix of rate-dependent materials was tested, with comparison to standard motorcycle helmet designs, with very promising results. Knowledge learned from this study will facilitate the development of a new generation of advanced motorcycle helmets that offer improved protection against both head and brain injuries.

Keywords: biomechanics; motorcycle accident; motorcycle helmet; skull fracture; concussion; subdural hematoma; brain injury; TBI

Introduction

In developing countries motorcycles are required for utilitarian purposes due to lower prices and greater fuel economy, whereas in the developed world they are considered a luxury and used mostly for recreation. In 2016 there were more than 134 million motorcycles worldwide [1], 8.4 million of which were registered in the United States, representing 3.2% of all US registered vehicles. California, Florida and Texas were the leading states in terms of the motorcycle popularity; collectively representing 22% of all US registered motorcycles [2]. In 2011, U.S. motorcyclists travelled a total of 18.5 billion miles, which, while only 0.6% of total vehicle miles travelled, accounted for 14.6% (4,612) of U.S. traffic fatalities that year. Worldwide there are more than 340,000 motorcyclist fatalities annually, which equates to more than 28% of all road accident deaths [3]. According to the U.S. National Highway Traffic Safety Administration (NHTSA) and other reports, 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 [4][5][6][7].

Two fundamental epidemiologic studies into the causation of motorcycle accidents have been conducted: the Hurt study in North America and the MAIDS study in Europe. According to the Hurt Report [8], 75 percent of collisions were found to involve a motorcycle and a passenger vehicle, while the remaining 25% were single vehicle accidents. The cause of motorcycle versus passenger vehicle collisions in 66% of accidents involves violation of the rider’s right of way due to the failure of motorists to detect and recognize motorcycles in traffic. Findings further indicate that severity of injury to the rider increases with alcohol consumption, motorcycle size and speed.

The most recent epidemiologic study to investigate motorcycle accident exposure data was conducted between 1999-2001 by a partnership of five European countries [9]. Findings show that passenger cars were again the most frequent collision partner (60%), where more than two-thirds of drivers reported that they did not see the motorcycle and more than half of all accidents involving motorcycles occurred at an intersection.

The COST report, which is an extension of the MAIDS study, documents that three-quarters (75%) of all motorcyclist deaths are a result of injury to the head and brain [10]. Linear forces were the major factor in 31% of fatal head injuries, while rotational forces were found to be the primary cause in over 60% of cases. While the helmet is considered the most effective means of rider protection [11], recent studies indicate that motorcycle helmets are only 37-42% successful in preventing fatal injury [12],[13]. By reducing peak linear forces acting on the head it was commonly believed that the risk of diffuse brain injuries, including concussion, subdural hematoma and diffuse axonal injury would also be prevented [8]. However, the biomechanical mechanisms of head and brain injuries are unique. New research shows that these mechanisms are poorly correlated [14].

Motorcycle Helmet Standards

Like most helmets, motorcycle helmets are modeled after ancient military helmets, the purpose of which is to provide protection against penetrating head injury, such as skull fracture. Whereas, all impacts have both linear and oblique components, which produce translational and tangential forces, respectively. The modern motorcycle helmet was introduced over 60 years ago [15]. Its outer shell serves as a second skull, diffusing impact forces over a larger surface area, while the inner liner compresses to minimize translational forces. However, a mechanism to mitigate tangential forces is absent. Since the liner fills the entire inner surface of the shell and is immobile, rotational inertia induced tangential forces are transmitted directly to the brain.

The likelihood of a helmeted motorcyclist sustaining impact loading injuries, such as skull fractures, can be determined by quantifying the magnitude of peak linear acceleration experienced by a test headform in response to impact. Whereas the risk of a rider suffering inertial or impulse loading injuries, such as concussion, axonal injury and intracranial hematoma can be computed based on impact-related angular kinematics at the headform center of mass [16],[17].

Unfortunately motorcycle helmet protection is not driven, for the most part, by advances in scientific knowledge, but by the need to meet applicable testing standards [18],[19]. In the United States, the governing specification is the federal motor vehicle safety standard (FMVSS) #218 [20]; the Snell Memorial Foundation also offers a voluntary standard M2015, which is a little more stringent [21]. Whereas BSI 6658 [22] and ECE 22.05 [23] have been adopted in European countries and AS/NZS 1698 accepted in Australasian countries [24]. Test protocols involve the guided fall of a helmeted headform onto steel anvils of various designs at impact velocities ranging from only 5.2 to 7.5 m/s (11-17 mph). The pass/fail criterion is based only on the helmet’s effectiveness in reducing peak linear acceleration, and thereby translational forces, in response to impact.

Impact-related angular head kinematics are not quantified under current motorcycle helmet standards, which therefore fail to assess whether helmets offer any protection against traumatic brain injuries. The omission of this critical measure of helmet performance is reflected epidemiologically in the disproportion of closed head and brain injuries in fatal motorcycle accidents [9,10].

Biomechanics of Head and Brain Injury

The two mechanisms associated with traumatic head and brain injury are impact loading and impulse loading, both of which are present in all impact events. Impact loading involves a blow directed through the center of mass of the head, resulting in translation of the head and brain. When thresholds of injury are exceeded, skull fractures [25], lacerations and contusions (bruising) to the head and underlying brain tissue may result [26]. Whereas, impulse or inertial loading is produced when an oblique impact, common to motorcycle crashes, creates tangential forces, causing head rotation. Since the brain is not rigidly attached to the inside of the skull, rotational inertia of the brain produces a mechanical strain on cerebral blood vessels, nerve fibers and brain tissue. When thresholds of injury are exceeded, nerve fibers in the brain may be damaged, producing concussion [27] and diffuse axonal injury (DAI) [28]. Blood vessels may also rupture, causing subdural hemorrhages (SDH) [29], the high mortality rate of which has motivated numerous studies of bridging vein failure properties [30],[31],[32],[33],[34],[35]. Subdural hematoma and traumatic axonal injury are frequently identified as the cause of serious injury or fatality in motorcycle accidents.

Holbourn [[36]] was the first to identify angular / rotational acceleration as the principal mechanism in brain injury. Gennarelli, Ommaya and Thibault further investigated the importance of rotational (angular) acceleration in brain injury causation, based on studies involving live primates and physical models, [28,29,[37],[38],[39], concluding that angular acceleration is far more critical than linear acceleration to the causality of traumatic brain injuries. They further isolated and investigated the unique effects of translational (linear) and inertial (angular) loading on the heads of primates [28], confirming that pure translation produces focal injuries, such as contusions and skull fractures, while rotationally induced inertial loading causes diffuse effects, including concussion and subdural hematoma. Closed head and brain injury, found in more than 60% of motorcycle accident fatalities, is due to inadequate helmet protection against impact-related angular head kinematics [10].

Skull fracture:

Ono [25] published thresholds for human skull fracture based on cadaver experiments. Twenty-five human cadaver skulls were exposed to frontal, occipital and lateral impacts. Each skull was covered with the rubber skin of a Hybrid II mannequin and filled with gelatin to accurately represent head mass. A series of 42 frontal, 36 occipital and 58 temporal blows were delivered to the suspended heads, during which linear accelerations were measured. A skull fracture threshold of 250 g for 3-millisecond impulse duration was established for frontal and occipital impacts, decreasing to 140 g for 7-millisecond impulse duration. Whereas the skull fracture threshold for lateral impacts is reported as 120 g over 3-millisecond duration, decreasing to 90 g over 7 milliseconds. Results indicate that skull fracture threshold is inversely related to impulse duration.

Concussion:

Several studies have attempted to establish biomechanical thresholds for concussion. Pellman et al. analyzed a series of video-recorded concussive impacts during NFL football games, reporting that concussive injury is possible at 45 g / 3500 rad/s2, while 5500 rad/s2 represents a 50% risk of concussive trauma [40]. Rowson and Duma, also using head injuries in America football as their model, conducted extensive laboratory and field-based biomechanical evaluations [41],[42],[43],[44]. Based on data from 62,974 sub-concussive impacts and 37 diagnosed concussions recorded using the Simbex, Inc. (Lebanon, NH) Head Impact Telemetry System (HITS), the investigators propose a concussion threshold of 104 ± 30 g and 4726 ± 1931 rad/s2.

Subdural Hematoma:

According to Gennarelli, the most common form of acute subdural hematoma (ASDH) is caused by shearing of veins that bridge the subdural space [29]. The severity of injury associated with bridging vein rupture has led to numerous studies of their mechanical properties (Lowenhielm [30-31,32], Lee and Haut [33], Meaney [34], and Depreitere [35]).

Lowenhielm tested 22 human parasagittal bridging vein samples from 11 decedents between the ages of 13 and 87 years without history of brain injury [30,31]. He hypothesized that blunt trauma to the head causes the brain to be displaced with respect to the dura, thereby stretching bridging veins and surrounding connective tissue. Based on his laboratory experiments, Lowenhielm found that maximal shear stresses occur about 7 milliseconds after impact, coinciding with bridging vein disruption. He concluded that bridging vein rupture may occur if peak angular acceleration exceeds 4500 rad/s2.

Depreitere subjected ten unembalmed human cadavers to 18 occipital impacts producing head rotation of varying magnitude and impulse duration in the sagittal plane [35]. Bridging vein ruptures, detected by autopsy, were produced in six impact tests. Findings suggest a mean tolerance level of approximately 6,000 rad/s2 for 10-millisecond impulse duration, which seems to decrease for longer impulse durations, however the confidence interval is rather broad due to the limited data set. Data from the research by Depreitere and Lowenhielm is presented in Figure 1.

Figure 1: Bridging vein failure as a function of impulse duration and peak angular acceleration (with line of best fit and 75% confidence intervals).Bridging vein failure relates to impulse duration and peak angular acceleration, with analysis showing the connection through a line of best fit and 75% confidence intervals. Helmets decrease peak translational force by extending the impulse duration. In the case of motorcycle helmets, typical impulse duration is approximately 12 milliseconds. With reference to Figure 1, above, this suggests that bridging vein rupture may result with peak angular accelerations in the order of 5,000 rad/s2, but may be as low as 3,000 rad/s2 after adjusting for standard error of the mean in this limited dataset.

While previous studies have investigated motorcycle impacts into vehicles and fixed barriers, the underlying motivation of such studies was to determine crush characteristics of the vehicles for accident reconstruction purposes [45]. Other studies have evaluated peak linear accelerations of the head, chest and pelvis of motorcyclists in collisions [46]. However, rotational forces associated with impact-related peak angular accelerations have not been determined even though it is well known that rotational mechanisms are the primary cause of closed head injuries [28,29,36-37,38,39] in helmeted motorcyclist accidents [10]. Measurement of impact-related head angular / rotational acceleration is critical to the development and evaluation of motorcycle helmets to provide effective protection against traumatic brain injuries associated with a range of typical motorcycle crash-related head impact speeds. To that end, this paper offers an objective determination of the performance of a variety of motorcycle helmets in terms of their ability to protect against both head and traumatic brain injuries associated with impact velocities reflective of typical head impact velocities in motorcycle accidents.

Methods

The standard test apparatus for impact testing of protective headwear was modified to enable measurement of both linear and angular headform kinematics [16]. This validated apparatus is comprised of parallel vertical braided stainless steel wires that guide the fall of a 50th percentile Hybrid III head and neck assembly (HumaneticsATD, Plymouth, MI) mounted to an aluminum flyarm. The anvil onto which the headform impacts consists of a 50 mm thick steel base plate, with a 100 mm thick concrete overlay, consistent with the coefficient of friction for typical roadway surfaces. Figure 2 illustrates this setup.

Figure 2: Modified Head drop system with Hybrid III head / neck

Modified Head Drop System with Hybrid III head/neck is a crash testing apparatus designed to simulate head impacts, using the Hybrid III dummy to measure injury potential by evaluating head and neck motion during collisions.

According to Mellor et al. [47] apparatus for the evaluation of protective headgear in which the headform is rigidly affixed to the carriage (flyarm) reduces the dissipation of energy by excessive rotation of the helmeted headform and sliding of the helmet on the anvil, thereby inflating peak linear acceleration measures. Examples in which the headform is rigidly affixed to the flyarm include the FMVSS218 test apparatus [20]. Whereas in Snell M2015 [21], BS 6658 [22] and AS/NZS 1698 [24] specifications the headform is attached to the flyarm by means of a hinge joint, which allows headform rotation in the sagittal plane as well as vertical translation, but prevents motion in the coronal and axial planes. The ECE 22:05 test method [23] utilizes a ball joint between the flyarm and headform, thereby permitting unrestricted head rotation in all three planes. Similar to the ECE test method, utilization of the Hybrid III neck permits headform rotation in sagittal, coronal and axial planes, but limits the rate of motion in a manner more consistent with the human musculoskeletal system [48]. Moreover, orientation of the Hybrid III neck was maintained relative to the flyarm, irrespective of headform orientation, thereby standardizing response of the neck form.

Instrumentation: A triaxial block, installed at the center of mass of the Hybrid III headform (HumaneticsATD, Plymouth, MI) housed a triaxial accelerometer from PCB Piezotronics (Depew, NY) and three DTS-ARS Pro angular rate sensors (Diversified Technical Systems, Seal Beach, CA). Data from the sensors were acquired using compact DAQ hardware from National Instruments (Austin, TX).

While all sensors had been calibrated by the respective manufacturers, verification tests were performed to validate linear and angular sensor calibration data. Calibration of the tri-axial linear accelerometer was validated using a portable handheld shaker and found to be within specification for all three axes of measurement. For the angular rate sensor a simple validation method was devised in which the sensor was affixed to a digital goniometer, which was moved through a set angle (Figure 3). Using LabView, the integral of angular rate was computed, reflecting concurrence with the digital goniometer for all three planes of motion.

Figure 3: Validation of Angular Rate Sensor Calibration

Validation of angular rate sensor calibration ensures the accuracy of sensors measuring rotational motion, confirming they are properly calibrated before being used in tests to assess impact and injury risks.

Ten motorcycle helmet models were selected for evaluation, based on popularity among motorcyclists, including representative models of full-coverage, three-quarter and half-helmet (shorty) styles, as shown in Figure 4, below. All models displayed the DOT certification sticker, indicating that their protective performance met the FMVSS218 motorcycle helmet testing standard [20]. Helmet sizes were chosen based on best fit for the Hybrid III headform, which has a 58cm head circumference, representative of a 50th percentile US adult male.

Figure 4: Motorcycle Helmet Models EvaluatedMotorcycle helmet models evaluated refers to the testing and comparison of various helmet designs to assess their safety, impact resistance, and effectiveness in protecting against head injuries during crashes.

In addition, a new prototype motorcycle helmet (Figure 5) was tested for comparison against the ten standard DOT motorcycle helmets. The prototype helmet was a three-quarter standard shell with liner constructed from a composite of rate-dependent materials arranged in a patent-pending matrix [49].

Figure 5: Motorcycle Helmet Prototype

Motorcycle helmet prototype refers to an experimental helmet design created for testing, aimed at evaluating its performance, safety features, and impact resistance before mass production.Five samples of each motorcycle helmet model were purchased in new condition. Each helmet was impacted one time in the frontal and/or occipital region at an impact velocity of approximately 8.3 meters per second (18.5 mph), which was verified computationally. Repeatability of the tests was confirmed at the start and end of data collection by dropping the Hybrid III headform from a height of 2.0 m onto a Modular Elastomer Programmer (MEP) pad of 25 mm thickness and durometer 60A. Standard Error of the Mean of 0.061 was computed based on peak angular accelerations for pre and post MEP pad drop tests.

Analysis: Analog sensor data were acquired at 20 kHz per channel, in accordance with SAE J211 [50], using LabView (National Instruments, Austin, TX). The raw data was then filtered in MATLAB (The MathWorks, Natick, MA) using a phaseless eighth-order Butterworth filter with cutoff frequencies of 1650 Hz and 300Hz for the linear accelerometers and angular rate sensors, respectively. Angular acceleration measures were computed from the angular velocity data using 5-point least-squares quartic equations. Impulse duration was determined based on the linear acceleration signal, where impulse start point is the time at which the magnitude of linear acceleration exceeds 3 g and impulse end point is the time at which the major component of linear acceleration crosses the y-axis (Figure 6). The gradient from impulse start point to peak was computed, as was the area under the acceleration magnitude curve from start to end points. Variables for the angular acceleration signal were similarly computed.

Figure 6: Impulse duration based on linear acceleration dataImpulse duration based on linear acceleration data refers to the length of time during which a force acts on an object, calculated from measurements of linear acceleration during an impact

An analysis method validated by Takhounts [51] establishes physical (strain and stress based) injury criteria for various types of brain injury based on scaled animal injury data and uses Anthropomorphic Test Device (ATD) test data to establish a kinematically based brain injury criterion (BrIC) for use with ATD impact testing. This method was utilized to express risk of brain injury according to the recently revised AIS scale [52] in terms of peak angular head kinematics, where:

The probability of brain injury for AIS 1-5 was thus computed as a function of BrIC:

The probability of brain injury for AIS 1-5 was computed as a function of BrIC (Brain Injury Criteria), correlating the severity of brain injuries (AIS 1-5) with the BrIC values to assess risk and outcomes.

Additionally, mechanical head and brain injury parameters of maximum pressure (in kPa), maximum principal strain (MPS) and cumulative strain damage measure (CDSM) were computed for each helmet impact test:

Lloyd-Biomechanics Motorcycle Helmets-Equations

Results

The following table presents a summary of results for each of helmet models evaluated:

Table 1: Summary of Results

Lloyd-Motorcycle Helmet Biomechanics -Table 1

* The best performing helmet for each variable is highlighted in green
* The worst performing helmet for each variable is highlighted in red

Motorcycle Helmet Protection against Skull Fracture:

Figure 7, below, presents peak linear acceleration values, averaged across 5 samples of each of the 10 motorcycle helmet models tested, along with results for the prototype, against pass/fail thresholds for current motorcycle helmet testing standards (DOT, Snell, BS and ECE) as well as frontal-occipital and lateral skull fracture thresholds, per Ono [25].

Figure 7: Risk of Skull Fracture Associated with Motorcycle Helmet ImpactsThe risk of skull fracture associated with motorcycle helmet impacts examines how helmet design and impact forces influence the likelihood of skull fractures during accidents, emphasizing the importance of effective helmet protection in reducing injury severity.

Results show that while all of the motorcycle helmet models evaluated satisfy at least the DOT standard, only the Scorpion T510 full-face helmet offers sufficient protection against fronto-occipital and lateral impacts at the moderate impact velocities at which the helmets were tested.

Motorcycle Helmet Protection against Concussion:

Figure 8 presents peak angular acceleration results for 8.3 m/s impacts onto a concrete anvil, averaged across 5 samples of each helmet model. The red horizontal line on figure 8 indicates the 50% threshold for concussive trauma, as defined by Pellman et al [40].

Figure 8: Risk of Concussion Associated with Motorcycle Helmet ImpactsThe risk of concussion associated with motorcycle helmet impacts evaluates how helmet design and impact forces contribute to the likelihood of concussions during crashes, highlighting the need for helmets that effectively absorb shock and reduce brain injury risks.

Results show that while a DOT approved motorcycle helmet may reduce peak angular acceleration associated with a helmeted head impact, the level of protection is not sufficient to prevent concussive injury in a typical motorcycle accident. Only the prototype motorcycle helmet, incorporating a liner constructed from a composite of rate-dependent materials arranged in a patent-pending matrix [49], offered adequate protection against concussive events.

Motorcycle Helmet Protection against Subdural Hematoma:

Figure 9, below, presents peak angular acceleration as a function of impulse duration, averaged across 5 samples of each of the 10 motorcycle helmet models tested, along with results for the prototype helmet. The threshold for bridging vein failure and resultant subdural hematoma is represented by the black line of best fit. Upper and lower boundary limits of this threshold are indicated in red, which represents a 75% likelihood that a subdural hematoma may occur for peak angular accelerations above the lower red line.

Figure 9: Risk of Subdural Hematoma Associated with Motorcycle Helmet ImpactThe risk of subdural hematoma associated with motorcycle helmet impact examines how helmet design and impact forces affect the likelihood of brain bleeding or blood clots, emphasizing the importance of helmet safety in preventing severe head injuries.

Most of the helmets tested, with exception of the prototype, fall above the lower threshold line suggesting the likelihood of catastrophic brain injury associated with a moderate helmeted impact. In fact, all but one of the five half-helmet models tested produced results above the mean threshold for subdural hematoma, indicating a higher likelihood of severe (AIS 4) or critical (AIS 5) brain injury. Overall, it appears that full-face helmets generally outperform half helmets in reducing the risk of subdural hematoma. Interestingly, an unhelmeted individual can seemingly withstand substantially greater peak angular accelerations and consequently experiences a lower risk of catastrophic brain trauma than a helmeted individual.

Correlation Analyses:

Pearson’s correlations were computed between each of the variables. Trends were suggested if computed R2 values were greater than 0.70, while strong correlations are indicated if R2 exceeded 0.80. Across all measures, the three most important variables, in rank order, for determining risk of head and brain injury are peak angular acceleration, angular acceleration gradient, and area under the angular acceleration curve between impulse start to end. The following interesting results were observed:

  • A negative trend exists between helmet mass and both linear acceleration (-0.70) and angular acceleration (-0.72). That is, both peak linear acceleration and peak angular acceleration seem to decrease as helmet mass increases.
  • There is neither a trend nor strong correlation between linear velocity and any of the variables investigated. This finding suggests that risk of head and brain injury is not related to impact speed.
  • A strong negative correlation exists between peak linear acceleration and impulse duration (-0.92). That is, impulse duration increases as peak linear acceleration decreases.
  • A trend, but not strong correlation was found between peak linear acceleration and peak angular acceleration, indicating that reducing impact-related peak linear acceleration may not necessarily mitigate peak angular acceleration.
  • Peak angular acceleration is strongly correlated with rotational injury criterion (RIC36) (0.95), Brain rotational Injury Criterion (BrIC) (0.93), probability of brain injury AIS 2 through 5 (μ=0.91), angular acceleration gradient (0.98), and area under the angular acceleration curve (0.96). A strong negative correlation is identified between peak angular acceleration and cumulative strain damage measure (CSDM) (-0.94) and maximum principal strain (MPS) (-0.94). A positive trend is also noted between peak angular acceleration and maximum pressure (0.77), Gadd Severity Index (GSI) (0.74) and linear acceleration gradient (0.76).

Discussion

As presented, the mechanisms associated with causation of focal head injuries and diffuse brain injuries are very different. Helmets were originally intended and continue to be designed to reduce the risk of potentially fatal head injuries caused by skull fracture fragments penetrating the brain. While skull fractures have been almost entirely eliminated in activities such as American Football, the higher impact speeds associated with motorcycle collisions continue to result in life-threatening cranial fractures, even in areas covered by the helmet. Thus, minimizing peak linear accelerations remains an important function of any motorcycle helmet. Therefore, to minimize the risk of skull fractures associated with helmeted motorcycle collision, based on research by Ono [25], a threshold of 140 g for peak linear acceleration to the frontal and occipital areas of the head and 90 g for peak linear acceleration for lateral impacts is suggested as a suitable performance criteria.

However, as with most helmets, motorcycle helmets perform inadequately in terms of mitigating the forces responsible for causing traumatic brain injury. Though a trend may exist between peak linear acceleration and peak angular acceleration, a strong correlation is absent, consistent with prior work in this area [14]. Hence, reduced peak linear acceleration through improved helmet design may not reduce the risk of traumatic brain injury. Indeed, as results herein show, an unhelmeted individual may be at a lesser risk of subdural hematoma during a moderate speed impact than one who is wearing a DOT approved motorcycle helmet.

Motorcycle Helmet Biomechanics

To minimize the risk of traumatic brain injury, spanning from mild concussion (AIS2) through severe brain injury (AIS5), it is necessary to reduce impact-related peak angular velocities in the sagittal, coronal and axial planes. Furthermore, since risk of subdural hematoma is defined based on peak angular acceleration and impulse duration, reducing peak angular velocities while also managing impulse duration will also lend to risk reduction of such severe or critical traumatic brain injuries. Therefore, to minimize the risk of concussion and subdural hematoma in helmeted motorcycle collisions, it is suggested that performance criteria based on peak angular velocity and acceleration not exceed 15.0 rad/s and 3,000 rad/s2, respectively, as previously proposed for American Football helmets [17].

Figure 10, below, was prepared to illustrate the relative effectiveness of the ten motorcycle helmet models tested and prototype in terms of protection against skull fracture, concussion and subdural hematoma, based on the above suggested performance criteria. Results indicate that only the prototype provides adequate protection against both traumatic head and brain injuries.

Figure 10: Motorcycle Helmet Effectiveness in Protecting Against Skull Fracture, Concussion and Subdural HematomaMotorcycle helmet effectiveness in protecting against skull fracture, concussion, and subdural hematoma evaluates how well different helmet designs prevent severe head injuries, including fractures, brain injuries, and bleeding, during accidents.

Based on the overall performance in terms of protection against skull fracture, concussion and subdural hematoma, and assuming equal weighting of these criteria for visualization purposes, the helmet models are presented in rank order in Figure 11.

Figure 11: Motorcycle Helmet Effectiveness
(presented in rank order from left to right)Motorcycle helmet effectiveness refers to the ability of a helmet to protect the rider from head injuries, such as skull fractures, concussions, and other traumatic brain injuries, by absorbing impact forces during a collision.

A strong negative correlation has been shown between helmet mass and both peak linear and angular accelerations. This finding suggests that ‘novelty’ motorcycle helmets (i.e. those not meeting FMVSS218 or other motorcycle helmet standards), which are often of lighter weight than DOT-approved helmets, will likely perform poorly in terms of preventing both head and brain injuries.

The new motorcycle helmet prototype evaluated within the scope of this study demonstrated exceptional potential to minimize the risk of traumatic brain injury, from mild concussion through severe brain injury, for a helmeted motorcyclist involved in a collision of moderate head impact speed.

Conclusions

The purpose of a motorcycle helmet is to reduce blunt force trauma to the head, thereby decreasing the risk of lacerations, contusions and skull fractures,. Whereas brain injuries may be produced when the brain lags behind sudden head motion thereby causing brain tissue, nerves and blood vessels to stretch and tear. The type of brain injury sustained is dependent on the magnitude and the time (pulse) duration over which mechanical stresses and strains act on the brain.

Motorcycle helmet test standards focus on reducing forces associated with linear acceleration by dropping helmeted headforms onto an anvil from a stated height and measuring the resultant peak linear acceleration. In general, the helmet design is considered acceptable if the magnitude of peak linear acceleration is less than an established threshold. Thus, helmets can and do prevent fatalities associated with penetrating head trauma. However, it may be argued that protection against brain injury is of paramount importance. After all, cuts, bruises and even bone fractures will heal, but brain injuries, if not fatal, often have life long neurologically devastating effects.

Current helmet testing standards do not require performance measures in terms of angular head kinematics and therefore fail to address whether motorcycle helmets provide the necessary protection against traumatic brain injuries. Research presented herein shows that it is possible to sustain catastrophic brain injuries, even while wearing a motorcycle helmet certified according to present testing standards.

Future generations of motorcycle helmets ought to be evaluated at higher impact velocities that are more indicative of head impact velocities in typical motorcycle accidents and should incorporate measures of both linear and angular acceleration to quantify their protective properties against both traumatic head and brain injuries.

References

[1]     RnR Market Research (2014) Market Research Reports Press Release: Global motorcycles market demand to rise 7.2% annually to 2016. accessed 7/21/2017

[2]     Statistica – The Statistics Portal. Number of Registered Motorcycles in the US by State. accessed 1/2/2017.

[3]     WHO (2013) Road traffic injuries. Fact Sheet No. 358. The World Health Organization, Geneva.

[4]     National Highway Transportation Safety Administration, Center for Statistics and Analysis (2007) NHTSA: Motorcycles Traffic Safety Fact Sheet DOT-HS-810-990. National Highway Traffic Safety Administration, Washington, DC.

[5]     Lin M, & Kraus J (2008) Methodological issues in motorcycle injury epidemiology. Accident Analysis and Prevention. 40 (5): 1653–1660. PMID: 18760092

[6]     Koornstra M, Broughton J, Esberger R, Glansdorp C, Koppel W, et al. (2003) Transport safety performance in the EU: a statistical overview. In: European Transport Safety Council, Brussels, Belgium.

[7]     Peden M (2004) The World Report on Road Traffic Injury Prevention. World Health Organization, Geneva.

[8]     Hurt HH, Ouellet JV & Thom DR (1981) Motorcycle Accident Cause Factors and Identification of Countermeasures. Volume 1: Technical Report. Traffic Safety Center, University of Southern California, Los Angeles, CA.

[9]     ACEM (2009) MAIDS (Motorcycle Accidents In Depth Study): In-depth investigations of accidents involving powered two wheelers – Final Report 2.0. European Association of Motorcycle Manufacturers.

[10]   Chinn B, Canaple B, Derler S, Doyle D, Otte D, et al. (2001) Cost 327, Motorcycle Safety Helmets, Final report of the action. European Commission, Directorate General for Energy and Transport, Belgium.

[11]   Chang L, Chang G, Huang J, Huang S, Liu D et al. (2003) Finite Element Analysis of the effect of motorcycle helmet materials against impact velocity. Journal of the Chinese Institute of Engineers. 26: 835–843.

[12]   National Highway Transportation Safety Administration (2008) Traffic Safety Facts, Data: Motorcycles. DOT HS 811 159. National Highway Traffic Safety Administration, Washington, DC.

[13]   Liu B, Ivers R, Norton R, Boufous S, Blows S, Lo SK (2008) Helmets for preventing injury in motorcycle riders. Cochrane Database Syst Rev. Jan 23; (1): CD004333. PMID: 18254047

[14]   Roy R (2007) Evaluation of Head Linear and Rotational Acceleration Response to Various Linear-Induced Impact Scenarios. Masters Thesis, University of Tennessee.

[15]   Roth H. and Lombard C (1953) Crash helmet. US patent 2,625,683.

[16]   Caccese V, Lloyd J, Ferguson J (2014) An Impact Test Apparatus for Protective Head Wear Testing Using a Hybrid III Head-Neck Assembly. Experimental Techniques. PMID: 28216804

[17]   Lloyd J & Conidi F (2015) Brain Injury in Sports. Journal of Neurosurgery. 124(3):667-74 PMID: 26473777

[18]   Newman J (2005) The biomechanics of head trauma and the development of the modern helmet. How far have we really come? In: Proceedings of the IRCOBI Conference, Prague.

[19]   Fernandez FAO & Alves de Sousa RJ (2013) Motorcycle helmets—A state of the art review. Accident Analysis and Prevention. 56:1-21. PMID: 23583353

[20]   U.S. Department of Transportation (2013) Federal Motor Carrier Safety Administration Standard No. 218, Motorcycle helmets. Washington, DC.

[21]   Snell (2015) M2020 – Standard for Protective Headgear for use with Motorcycles and other motorized vehicles. Snell Memorial Foundation, North Highlands, CA.

[22]   BSI (1985) BS 6658 – Specification for protective helmets for vehicle users. British Standards Institute.

[23]   ECE (2002) 22.05 Protective Helmets and their Visors for Drivers and Passengers of Motorcycles and Mopeds.

[24]   Australian/New Zealand Standard (2006) AS/NZS1698, Protective Helmets for Vehicle Users. Australian/New Zealand Standard.

[25]   Ono K (1998) Human head impact tolerance. In Yoganandan (Ed). Frontiers in Head and Neck Trauma: Clinical and Biomechanical. IOS Press, Amsterdam.

[26]   Nahum, A. M., Gatts, J. D., Gadd, C. W., Danforth, J (1993) Impact Tolerance of the Skull and Face. In Biomechanics of Impact Injury and Injury Tolerances of the Head-Neck Complex. Ed. Stanley H. Backaitis. Warrendale: Society of Automotive Engineers. 631-645.

[27]   Ommaya AK, Gennarelli TA (1974) Cerebral concussion and traumatic unconsciousness. Correlation of experimental and clinical observations of blunt head injuries. Brain. 97(4): 633-54. PMID: 4215541

[28]   Gennarelli TA, Thibault LE, Adams JH, Graham DI, Thompson CJ, et al (1982) Diffuse axonal injury and traumatic coma in the primate. Ann Neurol. 12(6): 564-74. PMID: 7159060

[29]   Gennarelli T. and Thibault L (1982) Biomechanics of Acute Subdural Hematoma, J Trauma. 22(8), 680-686. PMID: 7108984

[30]   Lowenhielm P (1974) Dynamic properties of the parasagittal bridging veins. Z. Rechtsmed. 74 (1): 55-62. PMID: 4832079

[31]   Lowenhielm P (1975) Strain Tolerance of the Vv. Cerebri sup. (Bridging Veins) Calculated from Head-on Collision Tests with Cadavers. Z. Rechtsmed. 75 (2): 131-144. PMID: 4217056

[32]   Lowenhielm P (1978) Tolerance level for bridging vein disruption calculated with a mathematical model. J Bioengineering. 2 (6): 501-507. PMID: 753840

[33]   Lee MC and Haut RC (1989) Insensitivity of tensile failure properties of human bridging veins to strain rate: implications in biomechanics of subdural hematoma. J Biomechanics. 22 (6-7): 537–542. PMID: 2808439

[34]   Meaney DF (1991) Biomechanics of acute subdural hematoma in the subhuman primate and man. University of Pennsylvania. PhD dissertation.

[35]   Depreitere B, Van Lierde CSloten JVVan Audekercke RVan der Perre G, et al. (2006) Mechanics of Acute Subdural Hematoma Resulting from Bridging Vein Rupture. J Neurosurgery. 104:950–956. PMID: 16776340

[36]   Holbourn AHS (1943) Mechanics of Head Injuries. The Lancet. 242(6267): 438-441.

[37]   Gennarelli TA, Thibault LE, and Ommaya AK. (1972) Pathophysiologic Responses to Rotational and Translational Accelerations of the Head. SAE Technical Paper 720970.

[38]   Gennarelli TA, Adams JH, Graham DI (1981) Acceleration induced head injury in the monkey I: The model, its mechanistic and physiological correlates. Acta Neuropathol. Suppl. 7:23-25. PMID: 6939241

[39]   Thibault LE and Gennarelli TA (1985) Biomechanics of diffuse brain injuries. Stapp Car Crash Conference. Twenty-Ninth Proceedings, SAE Paper No. 856022, New York.

[40]   Pellman EJ, Viano DC, Tucker AM, Casson IR, Waeckerle JF (2003) Concussion in professional football: reconstruction of game impacts and injuries. Neurosurgery. 53(4): 799-812. PMID: 14519212

[41]   Rowson S, Brolinson G, Goforth M, Dietter D, Duma S (2009) Linear and angular head acceleration measurements in collegiate football. J Biomech Eng. 131(6). PMID: 19449970

[42]   Rowson S, Goforth MW, Dietter D, Brolinson PG, Duma SM (2009) Correlating cumulative sub-concussive head impacts in football with player performance. Biomed Sci Instrum. 45:113-8. PMID: 19369749

[43]   Rowson S, Duma SM, Beckwith JG, Chu JJ, Greenwald RM, et al (2012) Rotational head kinematics in football impacts: an injury risk function for concussion. Ann Biomed Eng. 40(1): 1-13. PMID: 22012081

[44]   Rowson S, Duma SM (2013) Brain injury prediction: assessing the combined probability of concussion using linear and rotational head acceleration. Ann Biomed Eng. 41(5): 873-82. PMID: 23299827

[45]   Adamson KS, Alexander P, Robinson EL, Johnson GM, Burkhead CI, et al. (2002) Seventeen motorcycle crash tests into vehicles and a barrier. SAE 2002-01-0551. Society of Automotive Engineers, Warrendale, PA.

[46]   Severy DM, Brink HM, Blaisdell DM (1970) Motorcycle collision experiments. SAE Technical Paper 700897. Society of Automotive Engineers, Warrendale PA.

[47]   Mellor AN, St Clair VJM, Chinn BP (2007) Motorcyclists’ helmets and visors – test methods and new technologies. TRL Limited, Wokingham, Berkshire, UK. Project # S0232/VF.

[48]   Mertz HJ, Patrick LM (1971) Strength and Response of the Human Neck. Stapp Car Crash Conference; SAE Technical Paper 710855. Society of Automotive Engineers, Warrendale PA.

[49]   Lloyd JD (2015) Impact Absorbing Composite Material. US Patents Office. US20150246502A1.

[50]   SAE (2007) J211/1. Instrumentation for Impact Test – Part 1 – Electronic Instrumentation. Society of Automotive Engineers International, Surface Vehicle Recommended Practice, Warrendale, PA.

[51]   Takhounts EG, Craig MJ, Moorhouse K, McFadden J (2013) Development of Brain Injury Criteria (BrIC). Stapp Car Crash Journal 57: 243-266. PMID: 24435734

[52]   Abbreviated Injury Scale (2008) Association for the Advancement of Automotive Medicine, Des Plaines, IL.

New Helmet Technology Reduces Brain Injuries

Dr. John Lloyd, Research Director of Brains, Inc. announced today that football head injuries and concussions can be reduced up to 50 percent with their new helmet technology.

New Helmet Technology Reduces Brain Injuries - football helmet prototype by Dr. John Lloyd | expert

Tampa, FLJohn Lloyd PhD, Research Director of Brains, Inc. announced their latest breakthrough in football helmet safety today. The unique new helmet technology promises to provide up to 50 percent more protection against football head injuries and concussions. The helmet technology has wide application and can be used in every kind of helmet from baby helmets to military helmets, and for all athletes at risk of concussion and head injuries such as football players, cyclists, skiers, snowboarders, skateboarders, hockey players, baseball players, lacrosse players, boxers, soccer players, equestrian / horse-riding sports, such as polo and horse racing, as well as motorcycle and race car drivers.

Recent medical research documents found that concussions and cumulative head impacts can lead to lifelong neurological consequences such as chronic traumatic encephalopathy, a degenerative brain disease known as CTE and early Alzheimer’s.

The U.S. Centers for Disease Control and Prevention, estimates 1.6 – 3.8 million sport-related brain injuries annually in the United States. Of these 300,000 are attributed to youth football players, some of whom die from their injuries every year – a tragedy difficult for their mothers and families to recover from. The severity of the issue touching both the nation’s youth and professional athletes has led to thousands of lawsuits and Congressional Hearings. Growing concern has spread to the White House where President Obama recently spoke at the Healthy Kids and Safe Sports Concussion Summit.

New Helmet Technology Reduces Brain Injuries result

The BRAINS research team, led by renowned brain injury expert, Dr. John Lloyd, has worked for years on their project to help make sports safer. A controversial subject, some opponents have stated that concussion prevention is impossible. Dedicated to saving lives and preserving brain health, Dr. Lloyd and team persevered with their work leading to this new innovation. “Our results show that forces associated with concussion and brain injury are reduced more than 50% compared to similar testing with a leading football helmet,” said Dr. John Lloyd, Research Director. Results of our prototype helmet technology compared to the Riddell Revolution Speed varsity helmet are presented below: “The patent-pending matrix of non-Newtonian materials will not only benefit football, but can be utilized in all sports helmets as well as military, motorcycle and even baby helmets to improve protection and dramatically reduce the risk of brain injuries,” reported Dr. Lloyd. The materials are inexpensive, and produce a helmet that is considerably lighter and more comfortable than a traditional helmet.   Two additional applications of this new safety technology include medical flooring especially in hospitals and nursing homes or child play areas , as well as vehicle interiors.

Testing Methods: A modification to the NOCSAE standard test apparatus has been developed and validated for impact testing of protective headwear to include measurement of both linear and angular kinematics . This apparatus consists of a twin wire fall test system equipped with a drop arm that incorporates a 50th percentile Hybrid III head and neck assembly from HumaneticsATD. The aluminum flyarm runs on Teflon sleeves through parallel braided stainless steel wires, which are attached to mounting points in the building structure and anchored into the concrete foundation. The anvil onto which the head drop systems impacts consists of a 350mm x 350mm steel based plate. Both the Riddell Revolution Speed varsity football helmet and prototype helmet were dropped from a height 2.0 meters onto a flat steel anvil, in accordance with ASTM standards, generating an impact velocity of 6.2 m/s (13.9 mph). The following slow motion videos show testing on an unhelmeted head and prototype using this apparatus


Instrumentation:
A triaxial accelerometer from PCB Piezotronics (Depew, NY) and three DTS-ARS Pro 18k angular rate sensors (Diversified Technical Systems, Seal Beach, CA) affixed to a triaxial block were installed at the center of mass of the Hybrid III head form (HumaneticsATD, Plymouth, MI). Data from the accelerometer and angular rate sensors were acquired using National Instruments (Austin, TX) compact DAQ hardware.

Analysis: In accordance with SAE J211, data from the analog sensors were acquired at 10,000 Hz, per channel, using LabView (National Instruments, Austin, TX), then filtered in Matlab (The Mathworks, Natick, MA) using a phaseless 4th order Butterworth filter with a cut off frequency of 1650Hz. Angular acceleration measures were derived from the angular velocity data based on a 5-point least squares quartic equation.

About Lloyd Industries, Inc.

Lloyd Industries, Inc., located in San Antonio, Florida, is a research and development company focused on the biomechanics of brain injuries. The company was founded in 2004 by John D. Lloyd Bio, Ph.D., CPE, CBIS, Board Certified Ergonomist and Certified Brain Injury Specialist. He has also provided expert witness services nationwide for over 20 years in the fields of biomechanics, ergonomics and human factors, specializing in the biomechanics of brain injury, including sport and motorcycle helmet cases, slips and falls, motor vehicle accidents and pediatric head trauma. Lloyd Industries is open to licensing with manufacturers to bring this much-needed technology to market for the protection of sports participants and athletes of all ages. For additional information call 813-624-8986.