The impact response of motorcycle helmets at different impact severities

A Comparison of Motorcycle Helmet Wearing Intention and Behavior between Urban and Rural Areas

The motorcycle is one of the important modes of transport for Thai people in all provinces due to its convenience and ability to access all areas and cover short distances, which is especially convenient for rural people. However, according to the accident record, it was found that the motorcycle was the vehicle causing the highest amount of accidents, and helmet wearing could save lives and reduce the level of severe injuries. In this regard, the objective of this study was to study and develop a model of factors that affected helmet use behavior using structural equation modeling (SEM) based on the Health Belief Model (HBM). Further, this study compared urban and rural models, so as to suggest suitable guidelines for the promotion of helmet use in the study areas. The sample comprised 801 motorcycle users divided into 401 urban residents and 400 rural residents. From the parameter invariance testing in the two areas, a chi-square difference test found differences in the factor loading, intercepts, and structural paths between urban and rural societies.

Change in helmet use behavior enforced by CCTV cameras with automatic helmet use detection system on an urban arterial road

OBJECTIVE

Many developing countries experience a high death toll among motorcycle users (both drivers and passengers), primarily due to a relatively low rate of helmet use resulting from ineffective helmet law enforcement. The objectives of this study are to explore the change in helmet use behavior due to helmet use enforcement by closed-circuit television (CCTV) camera technology with an automatic helmet use detection system and to identify the factors associated with helmet use along an urban arterial road in the city of Khon Kaen, Thailand.

METHODS

Data collection was carried out on 49,128 samples by video cameras installed at 5 signalized intersections during 2 periods, namely, before and during the CCTV camera enforcement. The study applied logistic regression analysis to determine factors associated with helmet use and to compare the ratio of helmet use for each variable according to the odds ratio.

RESULTS

The study found that CCTV camera enforcement could increase helmet usage at all study intersections by 5.3%. The results imply that 4 factors, including riding status, number of passengers, day of week, and traffic conditions, significantly affected helmet use both before and during the CCTV camera enforcement. Remarkably, 2 more variables, age and police inspection, significantly affected helmet use during the CCTV camera enforcement period.

CONCLUSIONS

This study confirms that CCTV camera enforcement can be an important driving force for changing helmet use behavior, particularly for child passengers. Moreover, CCTV camera enforcement can support enforcement by extending coverage to a 24-h period and to intersections without police inspection.

A review of impact testing methods for headgear in sports: Considerations for improved prevention of head injury through research and standards

Standards for sports headgear were introduced as far back as the 1960s and many have remained substantially unchanged to present day. Since this time, headgear has virtually eliminated catastrophic head injuries such as skull fractures and changed the landscape of head injuries in sports. Mild traumatic brain injury (mTBI) is now a prevalent concern and the effectiveness of headgear in mitigating mTBI is inconclusive for most sports. Given that most current headgear standards are confined to attenuating linear head mechanics and recent brain injury studies have underscored the importance of angular mechanics in the genesis of mTBI, new or expanded standards are needed to foster headgear development and assess headgear performance that addresses all types of sport-related head and brain injuries. The aim of this review is to provide a basis for developing new sports headgear impact tests for standards by summarizing and critiquing: 1) impact testing procedures currently codified in published headgear standards for sports and 2) new or proposed headgear impact test procedures in published literature and/or relevant conferences. Research areas identified as needing further knowledge to support standards test development include defining sports-specific head impact conditions, establishing injury and age appropriate headgear assessment criteria, and the development of headgear specific head and neck surrogates for at-risk populations.

The determinants of motorcyclists helmet use: Urban arterial road in Khon Kaen City, Thailand

INTRODUCTION

Currently, Thailand incurs the highest death toll of motorcyclists in the world. The aim of this study was to explore the factors influencing helmet use of motorcyclists in Khon Kaen City, Thailand by using the Logistic regression analysis.

METHOD

The samples, consisting of 27,977 riders and 6,947 riding passengers, were collected by CCTV installed at several signalized intersections along urban arterial roads.

RESULTS

The observation results reveal that only 67% of motorcyclists wore the helmets. The analysis results reveal that the helmet use of motorcyclists was significantly associated with the riding status, number of passengers, apparent age, motorcycle class, time of day, the presence of police booths at intersections and, especially, red light running behavior. The riders tended to wear helmets at 2.7 times higher rates than passengers. Adult motorcyclists tended to wear the helmets at 2.8 times higher rates than children. The motorcyclists riding the motorcycles over 125 cc tended to wear the helmets 1.9 times higher than those riding motorcycles under 125 cc. The motorcyclists riding in the morning and the afternoon tended to wear the helmets 5.0 and 3.8 times higher than in the evening. The motorcyclists riding through intersections with police booths tended to wear the helmets 2.2 times higher than those riding through intersection without police booths. However, the red light running riders intend to wear the helmets 0.6 times less than the legal riders.

CONCLUSIONS

The outcome of this study could determine the factors influencing motorcyclist's helmet use.

PRACTICAL IMPLICATIONS

It will be useful for a development of 100% helmet use program designed to lessen the fatality of motorcyclists along the urban arterial roads.

The Association between Facial Fracture Patterns and Traumatic Head Injury in Injured Motorcycle Riders According to Helmet Use Status

Objective

This study was undertaken to identify the association between facial fracture patterns and traumatic head injury in injured motorcycle riders.

Methods

Retrospective study design. We reviewed the medical records of patients who underwent facial bone computed tomography (CT) and brain CT simultaneously among the injured motorcycle riders between May 2009 and July 2011. Data collected included age, sex, Glasgow Coma Scale (GCS), Revised Trauma Score (RTS), facial fracture patterns, head protective device (helmet) use, alcohol intake, time of accident and seat position. Facial fracture patterns were grouped as upper, mid, and lower face. Traumatic head injury (THI) included skull fracture, brain haemorrhage and diffuse axonal injury.

Results

Of the 154 patients included, 138 (89.6%) were male, 57 (37%) had facial fracture, 69 (44.8%) wore helmets and 30 (19.5%) had THI. Their mean age was 29.0+15.0 years. After multivariate logistic regression analysis, THI was associated with GCS, seat position of riders and accident time. THI was correlated with the combination of upper and midfacial fractures in helmeted group and isolated upper facial fracture or the combination of upper and midfacial fractures in unhelmeted group. The rest of facial fracture patterns were not correlated with THI regardless of helmet.

Conclusions

The combination of upper and midfacial fractures are the risk factor of THI regardless of helmet. The patients with the combination of upper and midfacial fractures should be further evaluated for head injury regardless of helmet.

The effect of motorcycle helmet fit on estimating head impact kinematics from residual liner crush

Proper helmet fit is important for optimizing head protection during an impact, yet many motorcyclists wear helmets that do not properly fit their heads. The goals of this study are i) to quantify how a mismatch in headform size and motorcycle helmet size affects headform peak acceleration and head injury criteria (HIC), and ii) to determine if peak acceleration, HIC, and impact speed can be estimated from the foam liner's maximum residual crush depth or residual crush volume. Shorty-style helmets (4 sizes of a single model) were tested on instrumented headforms (4 sizes) during linear impacts between 2.0 and 10.5m/s to the forehead region. Helmets were CT scanned to quantify residual crush depth and volume. Separate linear regression models were used to quantify how the response variables (peak acceleration (g), HIC, and impact speed (m/s)) were related to the predictor variables (maximum crush depth (mm), crush volume (cm³), and the difference in circumference between the helmet and headform (cm)). Overall, we found that increasingly oversized helmets reduced peak headform acceleration and HIC for a given impact speed for maximum residual crush depths less than 7.9mm and residual crush volume less than 40cm³. Below these levels of residual crush, we found that peak headform acceleration, HIC, and impact speed can be estimated from a helmet's residual crush. Above these crush thresholds, large variations in headform kinematics are present, possibly related to densification of the foam liner during the impact.

Preventive effects of motorcycle helmets on intracranial injury and mortality from severe road traffic injuries

INTRODUCTION

Road traffic injuries caused by motorcycle crashes are one of the major public health burdens leading to high mortality, functional disability, and high medical costs. The helmet is crucial protective equipment for motorcyclists. This study aimed to measure the protective effect of motorcycle helmets on clinical outcomes and to compare the effects of high- and low-speed motorcycle crashes.

METHODS

A cross-sectional observational study was conducted using a nationwide registry of severe trauma patients treated by emergency medical services (EMS) providers in Korea. The study population consisted of severe trauma patients injured in motorcycle crashes between January and December 2013. The primary and secondary outcomes were intracranial injury and in-hospital mortality. We calculated adjusted odds ratios (AORs) of helmet use and motorcycle speeds for study outcomes after adjusting for potential confounders.

RESULTS

Among 495 eligible patients, 105 (21.2%) patients were wearing helmets at the time of the crash, and 256 (51.7%) patients had intracranial injuries. The helmeted group was less likely to have an intracranial injury compared with the un-helmeted group (41.0% vs. 54.6%, AOR: 0.53 (0.33-0.84)). However, there was no significant difference in in-hospital mortality between the two groups (16.2% vs. 16.9%, AOR: 0.91 (0.49-1.69)). In the interaction analysis, there was a significant preventive effect of motorcycle helmet use on intracranial injury when the speed of the motorcycle was <30km/h (AOR: 0.50 (0.27-0.91)).

CONCLUSION

Wearing helmets for severe trauma patients in motorcycle crashes reduced intracranial injuries. The preventive effect on intracranial injury was significant in low-speed motorcycle crashes.

The impact response of traditional and BMX-style bicycle helmets at different impact severities

Bicycle helmets reduce the frequency and severity of severe to fatal head and brain injuries in bicycle crashes. Our goal here was to measure the impact attenuation performance of common bicycle helmets over a range of impact speeds. We performed 127 drop tests using 13 different bicycle helmet models (6 traditional style helmets and 7 BMX-style helmets) at impact speeds ranging from 1 to 10m/s onto a flat anvil. Helmets were struck on their left front and/or right front areas, a common impact location that was at or just below the test line of most bicycle helmet standards. All but one of the 10 certified helmet models remained below the 300g level at an impact speed of 6m/s, whereas none of the 3 uncertified helmets met this criterion. We found that the helmets with expanded polystyrene liners performed similarly and universally well. The single certified helmet with a polyurethane liner performed below the level expected by the Consumer Product Safety Commission (CPSC) standard at our impact location and the helmet structure failed during one of two supplemental tests of this helmet above the test line. Overall, we found that increased liner thickness generally reduced peak headform acceleration, particularly at higher impact speeds.

Bicycle helmets are highly effective at preventing head injury during head impact: head-form accelerations and injury criteria for helmeted and unhelmeted impacts

Cycling is a popular form of recreation and method of commuting with clear health benefits. However, cycling is not without risk. In Canada, cycling injuries are more common than in any other summer sport; and according to the US National Highway and Traffic Safety Administration, 52,000 cyclists were injured in the US in 2010. Head injuries account for approximately two-thirds of hospital admissions and three-quarters of fatal injuries among injured cyclists. In many jurisdictions and across all age levels, helmets have been adopted to mitigate risk of serious head injuries among cyclists and the majority of epidemiological literature suggests that helmets effectively reduce risk of injury. Critics have raised questions over the actual efficacy of helmets by pointing to weaknesses in existing helmet epidemiology including selection bias and lack of appropriate control for the type of impact sustained by the cyclist and the severity of the head impact. These criticisms demonstrate the difficulty in conducting epidemiology studies that will be regarded as definitive and the need for complementary biomechanical studies where confounding factors can be adequately controlled. In the bicycle helmet context, there is a paucity of biomechanical data comparing helmeted to unhelmeted head impacts and, to our knowledge, there is no data of this type available with contemporary helmets. In this research, our objective was to perform biomechanical testing of paired helmeted and unhelmeted head impacts using a validated anthropomorphic test headform and a range of drop heights between 0.5m and 3.0m, while measuring headform acceleration and Head Injury Criterion (HIC). In the 2m (6.3m/s) drops, the middle of our drop height range, the helmet reduced peak accelerations from 824g (unhelmeted) to 181g (helmeted) and HIC was reduced from 9667 (unhelmeted) to 1250 (helmeted). At realistic impact speeds of 5.4m/s (1.5m drop) and 6.3m/s (2.0m drop), bicycle helmets changed the probability of severe brain injury from extremely likely (99.9% risk at both 5.4 and 6.3m/s) to unlikely (9.3% and 30.6% risk at 1.5m and 2.0m drops respectively). These biomechanical results for acceleration and HIC, and the corresponding results for reduced risk of severe brain injury show that contemporary bicycle helmets are highly effective at reducing head injury metrics and the risk for severe brain injury in head impacts characteristic of bicycle crashes.

Motorcycle helmets--a state of the art review

This paper tries to make an overview of the work carried out by scientific community in the area of road helmets safety. In an area that is constantly being pushed forward by market competition, self-awareness of danger and tighter standards, several research groups around the world have contributed to safety gear improvement. In this work concepts related to head impact protection and energy absorption are explained. It also makes reference to the theories related to the development of helmets, as well as to the different existing types nowadays. The materials that are typically used in impact situations and new design concepts are also approached. In addition, it is presented a literature review of current--and most commonly used--helmet test standards, along with new tests and helmet concepts to assess the effects of rotational motion. In a non-restrictive, and never up-to-date report, a state-of-art review on road helmets safety is done, with a special insight into brain injury, helmet design and standards.

Examination of factors determining fault in two-vehicle motorcycle crashes

Motorcycle crashes frequently involve a combination of high-risk behaviors by the motorcyclist or the other crash-involved driver. Such behaviors may include riding or driving without appropriate licensure or while under the influence of alcohol, as well as deciding not to use a safety device such as a helmet or safety belt. Given that these factors frequently occur in combination with one another, it is difficult to untangle the specific effects of individual factors leading up to the crash outcome. This study assesses how various rider-, driver-, and other crash-specific factors contribute to at-fault status in two-vehicle motorcycle crashes, as well as how these same factors affect the propensity for other high-risk behaviors. Furthermore, the interrelationships among fault status and these other behaviors are also examined using a multivariate probit model. This model is developed using police-reported crash data for the years 2006-2010 from the State of Ohio. The results show that younger motorcyclists are more likely to be at-fault in the event of a collision, as are riders who are under the influence of alcohol, riding without insurance, or not wearing a helmet. Similarly, motorcyclists were less likely to be at-fault when the other driver was of younger age or was driving under the influence of alcohol, without insurance, or not wearing their safety belt. Crash-involved parties who engaged in one high-risk behavior were more likely to engage in other such behaviors, as well, and this finding was consistent for both motorcyclists and drivers. The results of this study suggest that educational and enforcement strategies aimed at addressing any one of these behaviors are likely to have tangential impacts on the other behaviors, as well.