Motorcyclist fatality rates and mandatory helmet-use laws

Using cross-sectional time series data for the 50 states and Washington, DC, covering the period 1975-2004, we estimate fixed effects regression models that examine the effects of universal and partial helmet laws on three different motorcyclist fatality rates, while controlling for other state policies and characteristics. Depending on the particular measure that is employed, states with universal helmet laws have motorcyclist fatality rates that are on average 22-33% lower in comparison to the experience with no helmet law. Additionally, partial coverage helmet laws are associated with reductions in motorcyclist fatality rates of 7-10%, on average.     

Helmet laws and motorcycle rider death rates

We investigated motorcycle rider death rates between states with full motorcycle helmet laws and those without. This was done using both unadjusted bivariate analyses and multivariate random-effects generalized least squares regression models of rider death rates. Multivariate models were adjusted for the competing influences of several explanatory variables, including the existence of a motorcycle helmet law. From 1994 to 1996, states with helmet laws experienced a median death rate of 6.20 riders per 10000 registered motorcycles and states without helmet laws experienced a median death rate of 5.07 riders per 10000 registered motorcycles (P = 0.008). After controlling for other factors that affect motorcycle rider fatalities (most notably population density and temperature), death rates in states with full helmet laws were shown to be lower on average than deaths rates in states without full helmet laws (P = 0.740). Our study weakens the claim that rider death rates are significantly lower in states without full motorcycle helmet laws.     

Generalized linear regression analysis of association of universal helmet laws with motorcyclist fatality rates

This study evaluates the association of universal helmet laws with U.S. motorcyclist fatality rates from 1993 through 2002 using climate measures as statistical controls for motorcycling activity via quasi-maximum likelihood generalized linear regression analyses. Results revealed that motorcyclist fatalities and injuries are strongly associated with normalized heating degree days and precipitation inches, and that universal helmet laws are associated with lower motorcyclist fatality rates when these climate measures, and their interaction, are statistically controlled. This study shows that climate measures have considerable promise as indirect measures (proxies) of motorcycling activity in generalized linear regression studies.     

Correlates of motorcycle helmet use among recent graduates of a motorcycle training course

Helmets significantly decrease morbidity and mortality from motorcycle crashes, but many areas of the world lack universal helmet laws. To educate motorcyclists in areas without helmet laws, more knowledge of motorcyclists’ helmet beliefs is needed.A web-based survey was therefore designed to assess motorcyclists’ attitudes, norms and behaviors towards helmets in a U.S. state with a limited helmet law. Of 445 survey respondents, 68.4% of respondents reported always wearing a helmet. The not-always-helmeted riders were more likely than the always-helmeted to be male; to bave less education; and to have a history of previous motorcycle crashes and injuries. Although both groups had taken rider training classes, fewer of the not-always-helmeted had learned how to ride in a class. The strongest correlates of being not-always-helmeted (vs. always-helmeted) were attitudes that helmets were not protective and impaired sight/hearing; and the normative belief that they would only wear helmets if forced by law. Because attitudes are often more easily changed than normative beliefs, education may increase helmet use. However, less than half of riders in this state with a mandatory education program learned how to ride from a rider education course, and 44% of non-helmeted said they would only wear a helmet if forced by law. Legislation may therefore be a more efficient and effective strategy than education to increase helmet use.     

Motorcyclist fatalities and the repeal of mandatory helmet wearing laws

Previous studies had estimated that repeal of mandatory helmet wearing laws resulted in increases in the number of fatalities ranging from nearly 40% to essentially zero. This study was performed to determine more definitively the influence on motorcyclist fatalities of these repeals. After repeal, motorcyclist fatalities increased more in the states which repealed their laws than in those which did not in 24 cases out of 26, with the 95% confidence interval for the average effect being 25 +/- 6%. It is therefore concluded that repeals of mandatory helmet wearing laws for motorcyclists were followed by substantial increases in motorcyclist fatalities.     

Bicycle helmet legislation: can we reach a consensus?

Debate continues over bicycle helmet laws. Proponents argue that case-control studies of voluntary wearing show helmets reduce head injuries. Opponents argue, even when legislation substantially increased percent helmet wearing, there was no obvious response in percentages of cyclist hospital admissions with head injury-trends for cyclists were virtually identical to those of other road users. Moreover, enforced laws discourage cycling, increasing the costs to society of obesity and lack of exercise and reducing overall safety of cycling through reduced safety in numbers. Countries with low helmet wearing have more cyclists and lower fatality rates per kilometre. Cost-benefit analyses are a useful tool to determine if interventions are worthwhile. The two published cost-benefit analyses of helmet law data found that the cost of buying helmets to satisfy legislation probably exceeded any savings in reduced head injuries. Analyses of other road safety measures, e.g. reducing speeding and drink-driving or treating accident blackspots, often show that benefits are significantly greater than costs. Assuming all parties agree that helmet laws should not be implemented unless benefits exceed costs, agreement is needed on how to derive monetary values for the consequences of helmet laws, including changes in injury rates, cycle-use and enjoyment of cycling. Suggestions are made concerning the data and methodology needed to help clarify the issue, e.g. relating pre- and post-law surveys of cycle use to numbers with head and other injuries and ensuring that trends are not confused with effects of increased helmet wearing.     

Barriers to, and factors associated, with observed motorcycle helmet use in Vietnam

This study investigated barriers to, and factors associated with, observed motorcycle helmet use among motorcyclists in Hai Duong Province, Vietnam. The findings highlighted an array of factors associated with observed helmet use namely, support for universal helmet legislation and a positive attitude towards what might be perceived as negative attributes of helmet use such as inconvenience and discomfort in hot weather. As well, older age (greater than 25 years in age), riding on a compulsory road, being a driver, trips of greater than 10 km, higher levels of education (having a university degree and higher) were found to be key determinants of helmet use. Despite over 95% of motorcyclists disagreeing with the statement that wearing a helmet does not reduce the severity of head injury in a crash, most motorcyclists believed that helmets did not need to be worn for a short trip. Overall, only 23% of motorcyclists were observed wearing a helmet. The authors conclude that efforts to increase helmet use need to focus on the necessity for universal helmet legislation in association with identifying solutions to reduce the negative attitudes towards helmet use.     

Fatal motorcycle accidents and helmet laws in Peninsular Malaysia

The objectives of this research are to determine the effect of helmet laws on fatalities associated with motor cycle accidents in Peninsular Malaysia. The prevalence of accidents and deaths occurring in the 10 groups of states of the Peninsula between 1973 and 1979 is analyzed. Differences in rates, especially the deaths/accidents, from before to after the introduction of the helmet law are emphasized. The rates accidents/1000 registrations and deaths/10,000 registrations decreased in almost all of the states after the law was introduced. There was not a uniform reduction in the rate of deaths/100 accidents after introduction of the law in individual states. However, a weighted linear regression shows that the effect of the introduction of the helmet law on deaths/accidents was significant. An odds ratio of 0.70 is the estimated risk of deaths associated with motorcycle accident after introduction of the helmet law compared with no helmet law. The 30 per cent estimated reduction in fatalities in Malaysia is similar in magnitude to that reported in the U.S.A. It is estimated that in 1979 the number of fatalities in Peninsular Malaysia was about 140 lower than could be expected without the helmet law.     

Motorcycle helmet use in relation to legal requirements

Helmet use by motorcyclists was observed in late 1978 in cities in six U.S. states with varying legal requirements regarding their use. In two cities (Baltimore, Maryland and Miami, Florida) in which all motorcyclists are legally required to wear helmets, virtually all wore helmets. In three cities (New Orleans, Louisiana, Phoenix, Arizona and Houston, Texas) where helmet use laws requiring use by all motorcyclists were changed in 1976 or 1977 so that use is required only by those less than 18 years old, wearing rates were 39, 46 and 63%, respectively. In Los Angeles, California, which has never had a law requiring helmet use, 46% wore helmets.

Based on these survey results, and on the known efficacy of helmets in reducing injuries to motorcyclists, the repeal of helmet laws that occurred in 26 states in 1976–1978 can be expected to result in major increases in motorcyclist deaths in succeeding years.     

Modeling motorcycle helmet use in Iowa: Evidence from six roadside observational surveys

This paper investigates the influence of type of roadway, weather conditions and other factors on motorcycle helmet use rates in Iowa. Using data from six statewide roadside observational surveys of motorcycle helmet use, a bivariate probit model is estimated. The applied methodological approach allows for potentially interrelated choices of motorcycle helmet use by drivers and passengers to be examined. The estimation results can enhance our understanding of other factors than state helmet laws which correlate with motorcycle rider helmet use, and the effect that the presence of a passenger has on motorcycle driver helmet use rates.     

Potential risk of using General Estimates System: Bicycle safety

Beneficial effects of bicycle helmet use have been reported mostly based on medical or survey data collected from hospitals. This study was to examine the validity of the United States General Estimates System (GES) database familiar to many transportation professionals for a beneficial effect of helmet use in reducing the severity of injury to bicyclists and found potential risk of erroneous conclusions that can be drawn by a narrowly focused study when the GES database is used. Although the focus of the study was on bicycle helmet use, its findings regarding potential risk might be true for any type of traffic safety study using the GES data. A partial proportional odds model reflecting intrinsic ordering of injury severity was mainly used. About 16,000 bicycle-involved traffic crash records occurring in 2003 through 2008 in the United States were extracted from the GES database.Using the 2003–2008 GES data, a beneficial effect of helmet use was found in 2007, yet a detrimental effect in 2004 and no effect in 2003, 2005, 2006, and 2008, which are contrary to the past findings from medical or hospital survey data. It was speculated that these mixed results might be attributable to a possible lack of representation of the GES data for bicycle-involved traffic crashes, which may be supported by the findings, such as the average helmet use rates at the time of the crashes varying from 12% in 2004 to 38% in 2008. This suggests that the GES data may not be a reliable source for studying narrowly focused issues such as the effect of helmet use. A considerable fluctuation over years in basic statistical values (e.g., average) of variables of interest (e.g., helmet use) may be an indication of a possible lack of representation of the GES data. In such a case, caution should be exercised in interpreting and generalizing analysis results.     

New composite liners for energy absorption purposes

This work studies the capacity of cork to act as material for the absorption of impact energy. Focus is given on the viability of hybrid paddings consisting of micro-agglomerate cork (MAC) and expanded polystyrene (EPS) through simulations of multi-impacts. EPS is a widely used material for energy absorption applications. However, once deformed, it shows no springback, which means that its capacity for energy absorption is greatly reduced after the first impact. On the other hand, cork is a viscoelastic material that has a good level of energy absorption capacity with almost total springback. An example in which EPS is commonly used is motorcycle helmet liners. In the first part of this work, a compression test is used to assess the effectiveness of the material laws chosen to model the cellular materials under study. Results show that the constitutive laws employed for EPS and micro-agglomerate cork adequately model the actual behaviour in springback absence. In the second part of this work, it was developed a simplified model of a road helmet energy absorption liner. This representative padding was subjected to double impacts as specified in an international helmet standard. The work also studies the use of MAC and EPS arrangements on the energy absorption linear through various configurations. Results were obtained with regard to the head centre of gravity acceleration, final padding thickness and the final weight of a helmet. Conclusions are drawn about the best configuration for the application under study.     

Changes in head injury with the New Zealand bicycle helmet law

It was claimed that the bicycle helmet law in New Zealand reduced head injuries to adult cyclists by 28% (Povey, L.J., Frith, W.J., Graham, P.G., 1999. Cycle helmet effectiveness in New Zealand. Accident Analysis and Prevention 31, 763-770). However, the pre-law increase in adults wearing helmets (from 30% in 1990 to 43% in 1993) was accompanied by a fall of 45 head injuries per 100 limb injuries (i.e. -3.47 for every 1% increase in helmet wearing) compared with a fall of 11 when wearing increased from 43 to 93% with the law (-0.23 for every 1% increase in wearing). Unless voluntary wearing is 15 times more effective in reducing head injuries, it seems likely that the apparent effects (as described by Povey et al., 1999) were an artefact caused by failure to fit time trends in their model. Such inconsistency of effects over periods of substantial change compared with periods of little change in helmet wearing may be a useful indicator of the presence of trends. Because the large increases in wearing with helmet laws have not resulted in any obvious change over and above existing trends, helmet laws and major helmet promotion campaigns are likely to prove less beneficial and less cost effective than proven road-safety measures, such as enforcement of speed limits and drink-driving laws, education of motorists and cyclists and treatment of accident black spots and known hazards for cyclists.     

The prevalence of non-standard helmet use and head injuries among motorcycle riders

OBJECTIVES: This study examined the prevalence of non-standard helmet use among motorcycle riders following introduction of a mandatory helmet use law and the prevalence of head injuries among a sample of non-standard helmet users involved in motorcycle crashes. METHODS: Motorcycle rider observations were conducted at 29 statewide locations in the 2 years following the introduction of the mandatory helmet use law in January, 1992. Medical records of motorcyclists who were injured in 1992 for whom a crash report was available and for whom medical care was administered in one of 28 hospitals were reviewed. Chi-squares and analysis of variance were used to describe differences between groups. RESULTS: Prevalence of non-standard helmet use averaged 10.2%, with a range across observation sites from 0 to 48.0%. Non-standard helmet use varied by type of roadway, day of week, and time of day. Injuries to the head were more frequent and of greater severity among those wearing non-standard helmets than both those wearing no helmet and those wearing standard helmets. CONCLUSIONS: Non-standard helmets appear to offer little head protection during a crash. Future study is needed to understand the dynamics leading to head injury when different types of helmets are worn.     

Evaluation of head response to ballistic helmet impacts using the finite element method

Injuries to the head caused by ballistic impacts are not well understood. Ballistic helmets provide good protection, but still, injuries to both the skull and brain occur. Today there is a lack of relevant test procedure to evaluate the efficiency of a ballistic helmet. The purpose of this project was (1) to study how different helmet shell stiffness affects the load levels in the human head during an impact, and (2) to study how different impact angles affects the load levels in the human head. A detailed finite element (FE) model of the human head, in combination with an FE model of a ballistic helmet (the US Personal Armour System Ground Troops’ (PASGT) geometry) was used. The head model has previously been validated against several impact tests on cadavers. The helmet model was validated against data from shooting tests. Focus was aimed on getting a realistic response of the coupling between the helmet and the head and not on modeling the helmet in detail. The studied data from the FE simulations were stress in the cranial bone, strain in the brain tissue, pressure in the brain, change in rotational velocity and translational and rotational acceleration. A parametric study was performed to see the influence of a variation in helmet shell stiffness on the outputs from the model. The effect of different impact angles was also studied. Dynamic helmet shell deflections larger than the initial distance between the shell and the skull should be avoided in order to protect the head from the most injurious threat levels. It is more likely that a fracture of the skull bone occurs if the inside of the helmet shell strikes the skull. Oblique ballistic impacts may in some cases cause higher strains in the brain tissue than pure radial ones.     

Factors associated with the relationship between motorcycle deaths and economic growth

This paper examines the Kuznets curve relationship for motorcycle deaths. The Kuznets curve describes the inverted U-shape relationship between economic development and, in this case, motorcycle deaths. In early stages of development we expect deaths to increase with increasing motorization. Eventually deaths decrease as technical, policy and political institutions respond to demands for increased safety. We examine this effect as well as some of the factors which might explain the Kuznets relationship: in particular motorcycle helmet laws, medical care and technology improvements, and variables representing the quality of political institutions. We apply a fixed effects negative binomial regression analysis on a panel of 25 countries covering the period 1970-1999. Our results broadly suggest that implementation of road safety regulation, improvement in the quality of political institutions, and medical care and technology developments have contributed to reduced motorcycle deaths.     

The impact of compulsory cycle helmet legislation on cyclist head injuries in New South Wales,Australia: A rejoinder

This paper challenges the conclusion of a recent paper by Walter et al. (Accident Analysis and Prevention 2011, doi:10.1016/j.aap.2011.05.029) reporting that despite numerous data limitations repealing the helmet legislation in Australia could not be justified. This conclusion is not warranted because of the limited time period used in their analysis and the lack of data beyond a few years before the introduction of legislation, the failure to adequately account for the effect of the phasing in of the legislation, the effect of the marked reduction in child cyclists, and the non-comparability of the pedestrian and cycling injuries and related lack of consideration of the severity of head injuries. The extent to which helmet legislation deters people from cycling is discussed.     

The effect of temperature on the capability of industrial safety helmets to absorb impact energy

The fundamental document specifying the requirements and testing methods applicable to industrial safety helmets in European Union member states is the standard EN 397:2012. According to that standard, one of the most important parameters of a helmet is shock absorption, determined for an impact of a striker with a kinetic energy of 49 J. The shock-absorbing performance of a safety helmet involves absorbing the energy of a striking object associated with a deformation of the shell and cradle, as well as an increase in the force transferred to the user’s head. The paper presents a study conducted with the aim to estimate the actual amount of energy absorbable by various helmet types without exceeding the threshold value of the force acting on the user’s head. A method of testing helmet deformation and the force acting on the helmet during an impact exerted by a falling object is presented. The effect of the temperature used for conditioning various helmet types on their capability to absorb impact energy was determined. The causes of deterioration of that capability due to temperature changes are analyzed for various designs of helmets made of different materials, and possible solutions to that problem are offered.     

The Cochrane Collaboration and bicycle helmets

Effective interventions for care of health need to be based on scientific evidence. To this end, the Cochrane Collaboration insists that its reviews should be based on reliable data, normally obtained by randomised controlled trial. To constitute evidence, data should also support a hypothesis in accord with scientific laws and knowledge. From these considerations, an appraisal is made of the conclusion of the Cochrane review Helmets for preventing head and facial injuries in bicyclists, that it establishes scientific evidence that all types of standard helmet protect against injuries to the brain. It is concluded that the review takes no account of scientific knowledge of types and mechanisms of brain injury. It provides, at best, evidence that hard-shell helmets, now rarely used, protect the brain from injury consequent upon damage to the skull. The review therefore is not a reliable guide to the efficacy of helmets and to interventions concerning their use.     

The relationship of alcohol safety laws to drinking drivers in fatal crashes

This paper presents an analysis of the relationships between the passage of key alcohol safety laws and the number of drinking drivers in fatal crashes. The study evaluated three major alcohol safety laws--administrative license revocation laws, 0.10 illegal per se, and 0.08 illegal per se laws--on the proportion of drinking drivers in fatal crashes. Drivers aged 21 and older in fatal crashes at two BAC levels--0.01-0.09 and 0.10 or greater--were considered separately. Drivers under age 21 were not included because they are affected by the Minimum Legal Drinking Age (MLDA) law. This study used data on drinking drivers in fatal crashes from the Fatality Analysis Reporting System (FARS) covering 16 years (1982-1997) for all 50 states and the District of Columbia. Also included in the study were such variables as per capita alcohol consumption and annual vehicle miles traveled (VMT), which could affect the number of alcohol-related crashes. The results indicate that each of the three laws had a significant relationship to the downward trend in alcohol-related fatal crashes in the United States over that period. This paper points out that this long-term trend is not the product of a single law. Instead, it is the result of the growing impact of several laws over time plus the affect of some factors not included in the model tested (such as the increasing use of sobriety checkpoints and the media's attention to the drinking-and-driving problem).