Scientific Journal Articles
on Bike Safety and Helmets
Summary: Here are references to a few of the many medical and scientific journal articles on the web about helmets and
bicycle safety. Most sources provide only the abstract summary for free. The articles below are in sections:
Injury and effectiveness -- mostly US
- The First Big One: The New England Journal of
Medicine article describing the Thompson and Rivara studies documenting the effectiveness of bicycle helmets. There
are references at the bottom to other medical journal articles. This article was the authoritative source most often
quoted on the potential for injury reduction by wearing a helmet. But its statistical findings of 85% effectiveness
were modified by the Second Big One, below and others that appeared subsequently.
- Meta analysis in 2022: This
New Zealand Medical Journal article by Ranul Makam confirms effectiveness rates: "Their meta-analysis of 40 studies
yielded an odds reduction of 51% for head, 69% for serious head, 33% for facial, and 65% for fatal head injuries."
Effectiveness of bicycle safety helmets in
preventing head injuries. A case-control study is a second study from the same team. The Journal of the
American Medical Association changes URL's from time to time. If the links do not work, this search for helmet articles on the
JAMA site should find most of them.
A Review of Cyclist Head Injury, Impact is a 2023 meta-analysis published in the Annals of Biomedical Engineering by Baker et al is a literature survey of studies who reported on helmet impact angles, speed of impact, point of impact, angle of impact and contact surface. "The considerable reduction in focal head pathologies is likely to be due to helmet standards mandating thresholds of linear acceleration. The less considerable reduction in diffuse brain injuries is likely to be due to the lack of monitoring head rotation in test methods. " That statement did not inspire us to buy the article.
Bicycle injuries and helmet use: a
systematic review and meta-analysis is a study published in 2016 in the International Journal of Epidemiology.
Forty studies were included in the meta-analysis with data from over 64,000 injured cyclists. For cyclists involved
in a crash or fall, helmet use was associated with odds reductions for head, serious head, face and fatal head
injury. No clear evidence of an association between helmet use and neck injury was found. Conclusions: Bicycle helmet
use was associated with reduced odds of head injury, serious head injury, facial injury and fatal head injury. The
reduction was greater for serious or fatal head injury. Neck injury was rare and not associated with helmet use.
Bicycle Helmets and Bicycle-Related Traumatic
Brain Injury in the Netherlands is a study published in 2020 by van den Brand et al that concludes: "In this
study we found that patients with TBI due to bicycle accidents did not wear helmets as often as a comparable control
group. This association could not be established for patients with TBI as a result of a collision between a bicycle
and a motorized vehicle. This study has some limitations, but the results strongly suggest that TBI in adult cyclists
could be reduced if cyclists in the Netherlands would wear a helmet more often. Future research should focus on
establishing the exact frequency of bicycle helmet use in the Netherlands and ways to promote helmet use without
Helmet use and bicycle-related trauma
injury outcomes Scott et al Journal of Brain Injury. Published online: 12 Sep 2019. Uses statistics from the
National Trauma Data Bank. "Results: Of the 76,032 bicyclists with head/neck injury, 22% worn helmets. The lowest was
among Blacks, Hispanics, and over 17 years old. Wearing a helmet significantly reduces injury severity, HLOS, ICULOS,
and mortality (i.e total and in-hospital). Males had a severe injury, longer HLOS, ICULOS, and higher mortality than
female. Blacks and Hispanics had longer HLOS and ICULOS and higher total mortality than Whites, but had a similar
chance for in-hospital mortality."
- A 2019 study Injuries
associated with electric-powered bikes and scooters: analysis of US consumer product data published in Injury
Prevention by DiMaggio et al. found that E-bike and powered scooter injury patterns differ from more traditional
pedal bicycles. Riders using E-bikes were more likely to suffer internal injuries and require hospital admission.
Powered scooter injuries were nearly three times more likely to result in a diagnosis of concussion. E-bike-related
injuries were also more than three times more likely to involve a collision with a pedestrian than either pedal
bicycles or powered scooters, but found no evidence that powered scooters were more likely than bicycles to be involved
in a collision with a pedestrian. While rates of pedal bicycle-related injuries have been decreasing, reported E-bike
injuries have been increasing.
- A 2017 study from Traffic Injury
Prevention is titled "Bicycle helmet effectiveness is not overstated." Conclusions: "Despite potential
weaknesses with case-control study designs, the best available evidence suggests that helmet use is an effective
measure of reducing cycling head injury."
- A 2017 study from
International Journal of Epidemiology is titled "Bicycle injuries and helmet use: a systematic review and
meta-analysis" Conclusions: "Bicycle helmet use was associated with reduced odds of head injury, serious head injury,
facial injury and fatal head injury. The reduction was greater for serious or fatal head injury. Neck injury was rare
and not associated with helmet use. These results support the use of strategies to increase the uptake of bicycle
helmets as part of a comprehensive cycling safety plan."
- A 2016 study from the Journal of Injury Epidemiology
by Ruchi Kaushik and colleagues at the Mayo Clinic Children's Center. They studied data from a single county with no
helmet law. ".. Of patients with head injuries, 17.4 % were documented to have been wearing a helmet, 44.8 % were
documented as not wearing a helmet, and 37.8 % had no helmet use documentation. Patients with a head injury who were
documented as not wearing a helmet were significantly more likely to undergo imaging of the head (32.1 percent vs. 11.5
%) and to experience a brain injury (28.1 vs. 13.8 %)." Of the most seriously injured: "Of the 500 patients who
suffered head injuries, 11 required PICU admission or succumbed to their injuries. Of these 11 patients, 10 were not
wearing a helmet and 1 had no documentation regarding helmet use."
- Bicycle helmets work when it matters the most by Joseph Bellal MD et al:
Results: A total of 6,267 patients were included. About 25.1% of bicycle riders were helmeted. Overall, 52.4% of the
patients had severe TBI, and the mortality rate was 2.8%. Helmeted bicycle riders had 51% reduced odds of severe TBI
and 44% reduced odds of mortality. Helmet use also reduced the odds of facial fractures by 31%. "CONCLUSION: Bicycle
helmet use provides protection against severe TBI, reduces facial fractures, and saves lives even after sustaining an
- Effect of helmet use on maxillofacial injuries due to bicycle and scooter accidents: a systematic literature review and meta-analysis by Stassen et al.
This study concludes that bicycle helmets significantly reduce facial injuries and calls for mandatory helmet laws.
- A 2014 study from the American
Journal of Public Health by Janessa M. Graves, PhD, MPH et al was the first to look at the effects of public
bike share programs:
Results: "In PBSP cities, the proportion of head injuries among bicycle-related injuries increased from 42.3% before
PBSP implementation to 50.1% after... Conclusions: Results suggest that steps should be taken to make helmets
available with PBSPs. Helmet availability should be incorporated into PBSP planning and funding, not considered an
afterthought following implementation."
- And a 2013 study from Australia: The
effectiveness of helmets in bicycle collisions with motor vehicles: A case-control study. This study showed that
"Helmet use was associated with reduced risk of head injury in bicycle collisions with motor vehicles of up to 74%, and
the more severe the injury considered, the greater the reduction. This was also found to be true for particular head
injuries such as skull fractures, intracranial injury and open head wounds. Around one half of children and adolescents
less than 19 years were not wearing a helmet, an issue that needs to be addressed in light of the demonstrated
effectiveness of helmets. Non-helmeted cyclists were more likely to display risky riding behaviour, however, were less
likely to cycle in risky areas; the net result of which was that they were more likely to be involved in more severe
- A 2016 study in the International Journal of Epidemiology (1-15 doi: 10.1093/ije/dyw153) by Jake Olivier and
Prudence Creighton: Bicycle injuries and helmet use: a systematic review and meta-analysis. This study
included 40 studies were in the meta-analysis with data from over 64 000 injured cyclists. For cyclists involved in a
crash or fall, helmet use was associated with odds reductions for head, serious head , face and fatal head injury. No
clear evidence of an association between helmet use and neck injury was found. Conclusions: Bicycle helmet use was
associated with reduced odds of head injury, serious head injury, facial injury and fatal head injury. The reduction
was greater for serious or fatal head injury.
- A 2017 study from Traffic Injury Prevention by Jake Olivier &
Igor Radun (2017): "Bicycle helmet effectiveness is not overstated" discusses challenges in estimating bicycle helmet
effectiveness from case-control studies, provide evidence that odds ratios using hospital controls likely underestimate
helmet effectiveness, and proposes areas of further study.
A computational simulation study of the
influence of helmet wearing on head injury risk in adult cyclists Simulations were run over a range of bike and
car speeds. Bicycle helmets were found to be effective in reducing the severity of head injuries sustained in
frequent crashes. They reduced the risk of a severe (greater than AIS3) injury in crashes with head impacts by an
average of 40%. In crashes likely to cause up to moderate (AIS2) injuries to an unprotected rider, a helmet
eliminated the risk of injury. Helmets were also found to prevent fatal head injuries in some instances. The study
demonstrated the effectiveness of helmets over the entire range of speeds. Helmets were also found to be protective
of neck injuries in many cases. Helmets offered an increase in protection even when an increase in speed due to risk
compensation was factored in. There are illustrations of the simulations on the linked website.
The Journal of Injury Prevention This 2003 study by
P. L. Jacobsen is titled "Safety in numbers: more walkers and bicyclists, safer walking and bicycling." The author
examined statistics for many countries and found that the more cyclists and pedestrians there are on the streets, the
safer they all are. And an article in Berkeley's Planetizen
newsletter discusses other studies showing that pedestrians are safer as well. Riding in a place like the
Netherlands or another location where there is lots of bike traffic will tell you that the thesis is correct, and
these studies attempted to document it. Those who oppose helmet laws contend that the laws reduce cycling, thereby
increasing the risk to each cyclist left on the streets. There is no evidence of that in the US.
Bicycle-associated head injuries and deaths in
the United States from 1984 through 1988. How many are preventable? Main results: "From 1984 through 1988,
bicycling accounted for 2985 head injury deaths (62% of all bicycling deaths) and 905 752 head injuries (32% of
persons with bicycling injuries treated at an emergency department). Forty-one percent of head injury deaths and 76%
of head injuries occurred among children less than 15 years of age. Universal use of helmets by all bicyclists could
have prevented as many as 2500 deaths and 757 000 head injuries, ie, one death every day and one head injury every 4
Circumstances and Severity of Bicycle Injuries - Summary
Report of Harborview Helmet Studies A study sponsored by the Snell Foundation and published by Snell, not a
journal. Has interesting data on the location of helmet impacts.
Use of Alcohol as a Risk Factor for Bicycling
Injury From the Journal of the American Medical Association.
Elevated Blood Alcohol and Risk of Injury Among
Bicyclists From the Journal of the American Medical Association.
Caloric Imbalance and Public Health Policy.
This 1999 article from the Journal of the American Medical Association discussed obesity and exercise, a prime
reason for promoting bicycle use, opening with a statement that obesity had become an epidemic.
Alcohol and Motor Vehicle-Related Deaths of Children
as Passengers, Pedestrians, and Bicyclists From the Journal of the American Medical Association.
Unpowered Scooter-Related Injuries--United States,
1998-2000. (You have to page forward in this .pdf file to find the article.) From the Journal of the American
Helmet legislation effectiveness in three NY counties - Dr Douglas R. Puder et. al. of the
Department of Pediatrics, Nyack Hospital, Nyack NY November, 1999, issue of the American Journal of Public
Risk Factors for Injuries from in-Line Skating
and the Effectiveness of Safety Gear by Schieber et al was a study done in 1996 that concluded: "Wrist injuries were the most common (32 percent); 25 percent of all injuries were wrist fractures. Seven percent of injured skaters wore all the types of safety gear; 46 percent wore none. Forty-five percent wore knee pads, 33 percent wrist guards, 28 percent elbow pads, and 20 percent helmets. " and "The effectiveness of helmets could not be assessed."
Bicycle helmet use by children. Evaluation of a
community-wide helmet campaign. From the Journal of the American Medical Association
Profile of Pediatric Bicycle Injuries from the
Southern Medical Journal. "Bicycle injuries accounted for 18% of all pediatric trauma alert patients. The mean
age of injured children was 10 years, and 79% were males. Bicycle-motor vehicle collisions caused 84% of injuries.
Only 3 children (1.4%) wore bicycle helmets. Resulting injuries included external wounds (86%), head injuries (47%),
fractures (29%), and internal organs (9%). Six children died. You have to register with Medscape to read the article,
but it's free.
- The Cost of Traumatic Brain Injury and Its Prevention in the United States by Ted R. Miller, Eduard Zaloshnja, and
Delia Hendrie is a chapter in the very expensive book Neurotrauma and Critical Care of the Brain by U. Drews and
Christopher M. Loftus. Midway through the chapter (p 453) it presents a return on investment analysis of the value of
bicycle helmets. The book was published in 2009.
Influence of Socioeconomic Status on the Effectiveness of Bicycle Helmet
Legislation for Children: A Prospective Observational Study Patricia C. Parkin, MD, Amina Khambalia, MSc, Leanne
Kmet, MSc, Colin Macarthur, MBChB, PhD. PEDIATRICS Vol. 112 No. 3 September 2003, pp. e192-e196 ELECTRONIC ARTICLE
Abstract says "This study showed that bicycle helmet use by children increased significantly after helmet
legislation. In this urban area with socioeconomic diversity and in the context of prelegislation promotion and
educational activities, the legislative effect was most powerful among children who resided in low-income areas."
Bicycle Helmet Use Among Maryland Children: Effect of Legislation and
Education. Timothy R. Coté, Jeffrey J. Sacks, Marcie-jo Kresnow, Deborah A. Lambert-Huber, Ellen R. Schmidt,
Andrew L. Dannenberg, and Cynthia M. Lipsitz Pediatrics, Jun 1992; 89: 1216 - 1220. Prelaw and postlaw helmet use was
observed in Howard County (with a pre-law police campaign) and two control counties: Montgomery (with a community
education program) and Baltimore County (no helmet activities). Prelaw helmet use rates for children were 4% for
Howard, 8% for Montgomery, and 19% for Baltimore. Postlaw rates were 47%, 19%, and 4%, respectively.
Children's bicycle helmet use and injuries in
Hillsborough County, Florida before and after helmet legislation K D Liller et al. Explored the changes in
children's bicycle helmet use and motor vehicle bicycle related injuries in Hillsborough County, Florida before and
after passage of the state bicycle helmet law. The results show a significant increase in bicycle helmet use among
children, ages 5-13, in the post-law years compared with the pre-law years. Also, there has been a significant
decline in the rates of bicycle related motor vehicle injuries among children in the post-law years compared with the
pre-law years. Although there have been complementary educational and outreach activities in the county to support
helmet use, it appears that the greatest increase in use occurred after the passage of the helmet law.
This study of ebike head injuries
included 20 riders and pedestrians, all under 18. Seventeen of them had head injuries. None had been wearing a
helmet. One died.
- An Outstanding Science Fair Project: J. Raleigh Burt produced a 2005 science project called Dangerous Decision: The
Consideration for Helmet Use At Any Speed." He convincingly demonstrates that a simple tipover fall from a
bicycle onto pavement at zero forward speed can cause a head injury, and further concludes that helmets meeting current
standards are likely to prevent it. The project won awards at two Colorado state-level science fairs. You can read
about it on this science blog.
Children Should Wear Helmets While Ice-Skating: A Comparison of
Skating-Related Injuries. An article comparing head injuries in skateboarding, roller skating, inline skating and
ice skating that appeared in the July, 2004 edition of Pediatrics. The authors found similar head injury
patterns and recommended that ice skaters wear helmets.
- Preventing bicycle-related injuries: next steps Frederick Rivara and Richard W Sattin. Injury Prevention
2011;17:215 doi:10.1136/injuryprev-2011-040046. Bicycling can be a valuable part of the program to deal with obesity.
Head injury is a discouragement to riding. "Head injury is by far the greatest risk posed to bicyclists, comprising
one-third of emergency department visits, two-thirds of hospital admissions, and three-quarters of deaths. "Since 1999,
in the USA, the number and rate of bicycle-related deaths has decreased for those aged 16 years or less from 213 (0.31
per 100,000) to 118 (0.17 per 100,000) in 2007.2 The number and rate of cycle-related deaths for those aged 17 or more,
however, has increased during that same period from 586 (0.28 per 100,000) to 700 (0.30 per 100,000). Among those aged
16 or less, the number of non-fatal bicycle-related injuries in the USA decreased from about 316,000 in 2001 to 261,000
in 2009, whereas for those older than 16, the number of injuries increased from about 202,000 in 2001 to 258,000 in
2009." The authors discuss strategies to promote cycling, off-road trails, factors that might alter the risk of injury
to road cyclists, mountain biking injuries and low rates of helmet use nationwide. They conclude that "New research,
different approaches, and better implementation of findings" are needed.
- Bicycle-Related Injuries Among Children and Adolescents in the United States.
Mehan TJ, Gardner R, Smith GA, McKenzie LB. Clin Pediatr 2008; ePub(ePub): ePub. DOI: 10.1177/0009922808324952
Describes the epidemiology of US bicycle-related injuries among children and adolescents 18 years and younger. Analyzes
NEISS data for patients seen in emergency rooms 1990 to 2005 who were injured while operating a bicycle. During the
study period an estimated 6,228,700 individuals 18 years and younger were treated for bicycle-related injuries.
Children with head injuries were more than 3 (relative risk, 3.63) times as likely to require hospitalization and were
almost 6 (relative risk, 5.77) times more likely to have their injuries result in death. The authors concluded that the
large number of bicycle-related injuries indicates that prevention of these injuries should remain an important area of
bicycle safety research and practice.
- Bicycle Helmet Assessment During Well Visits Reveals Severe Shortcomings in Condition and Fit. Gregory W.
Parkinson, MD, FAAP and Kelly E. Hike, BA, Falmouth Pediatric Associates, Falmouth, MA. PEDIATRICS Vol. 112 No. 2
August 2003, pp. 320-323. Results. Eighty-four percent (395/473) of eligible families participated. A total of 479
participants were assessed. Eighty-eight percent of participants (419/478) owned a helmet. Reported helmet use "always"
or "almost always" was 73% for bicycling (317/434), 69% for in-line skating (193/279), 58% for scootering (179/310),
and 50% for skateboarding (79/158). Compared with younger children, teenagers were less likely to wear helmets for all
activities. Complete pass rate for every aspect of condition and fit was 4% (20/478, 95% confidence interval: 3-6). The
pass rate when the parent alone fit the helmet was 0% (0/52). Three individual aspects of fit were most problematic: 1)
helmet 'resting position' too high on the forehead (pass rate 249/479; 52%), 2) improper strap position (pass rate
157/476; 33%), and 3) excessive movement of the helmet from front to back of the head (pass rate 247/479; 52%). Mean
time for questionnaire completion was 4 (standard deviation: +/-1) minutes, and 7 (standard deviation: +/-3) minutes
for helmet assessment. Conclusions. Ninety-six percent of children and adolescents wore helmets in inadequate
condition and/or with inadequate fit. This occurred despite a high acceptance of helmet use by this population.
Lights Out: Can contact sports lower your
intelligence? This article appeared in Discover Magazine back in 2004, before the current attention to
concussion had begun. Although not a peer-reviewed journal article, it is available to the public for free, and is
still a very interesting source of info on concussion levels and mechanisms.
Analyzing Pediatric Bicycle
Injuries using Geo-Demographic Data published in the Journal of Pediatric Surgery found that: "Low-income
neighborhoods and those near major roadways held the highest risk for pediatric bicycle accidents. Use of helmets was
extremely low in the patient population, with high rates of traumatic brain injury."
- Bicycle safety helmet legislation and bicycle-related non-fatal injuries in California. by Brian Ho-Yin Lee, Joseph
L. Schofer and Frank S. Koppelman. Accident Analysis & Prevention, Volume 37, Issue 1 , January 2005, Pages 93-102.
Compared developments in injury rates in California after adoption of helmet legislation covering kids. Adult rates did
not change, while traumatic brain injuries among child riders went down 18%. We have a lot of questions about the data
and the assumptions of this study. Available online for $30.
sponsored by the NFL Players Association developed a lot of good info on concussion. Here is another
Neurosurgery article from that data concluding that "dementia-related syndromes may be initiated by
repetitive cerebral concussions in professional football players." Although most bicycle riders do not suffer
repetitive concussions, some do.
Collaboration study found that helmet legislation "appears to be effective in increasing helmet use and
decreasing head injury rates in the populations for which it is implemented. However, there are very few high quality
evaluative studies that measure these outcomes, and none that reported data on possible declines in bicycle use."
- Intended and Unintended Effects of Youth Bicycle Helmet Laws a paper once available on the University of California
- Irvine Department of Education site that concludes that passing a state-wide bicycle helmet law reduces cycling by
those who are covered by the law by 4 to 5 per cent.
Demographic, socioeconomic, and attitudinal associations with children's cycle-helmet use in the absence of
legislation and article that concludes using self-reported data from school kids that attitudes are probably the
most important determinant of helmet wearing. We have not seen the whole article and can't imagine how the result
could have been different. But we never put any stock in child studies using self-reported data anyway, since the
kids tell you whatever they think they should be telling you.
and facial injury risk in relation to helmet fit: a case-control study calculates risk factors for helmets that
fit poorly, and how much that they increase the risk of head and facial injury.
Protective equipment in youth ice hockey: are mouthguards and helmet age relevant to concussion risk? Kolstad et al.
This 2023 Canadian study of hockey players found that mouthguards were effective in reducing concussion risk: "Players who reported wearing a mouthguard had a 28% lower concussion rate (IRR=0.72, 95% CI 0.56 to 0.93) and 57% lower odds of concussion (OR=0.43, 95% CI 0.27 to 0.70) compared with non-wearers.
Motorcycle helmets do
not injure necks reports this 2011 page on a Johns Hopkins study. We don't have the journal citation for it.
Awareness of the bicycle helmet law in North Carolina reports on a study using a written survey that found that
the majority of those returning the survey said they were aware that North Carolina has a helmet law.
The impact of bicycle helmet legislation on cycling fatalities in Australia: Olivier J, Boufous S, Grzebieta R.
Int. J. Epidemiol. 2019; ePub(ePub): ePub. This 2019 study concludes:
"RESULTS: Immediately following bicycle helmet legislation, the rate of bicycle fatalities per 1?000?000 population
reduced by 46% relative to the pre-legislation trend [95% confidence interval (CI): 31, 58]. For the period
1990-2016, we estimate 1332 fewer cycling fatalities (95% CI: 1201, 1463) or an average of 49.4 per year (95% CI:
44.5, 54.2). Reductions were also observed for pedestrian fatalities; however, bicycle fatalities declined by 36%
relative to pedestrian fatalities (95% CI: 12, 54).
"CONCLUSIONS: In the absence of robust evidence showing a decline in cycling exposure following helmet legislation or
other confounding factors, the reduction in Australian bicycle-related fatality appears to be primarily due to
increased helmet use and not other factors."
Two Australian studies have concluded that critiques of their helmet laws are
The effectiveness of helmets in bicycle
collisions with motor vehicles: A case-control study. This 2013 study showed that "Helmet use was associated with
reduced risk of head injury in bicycle collisions with motor vehicles of up to 74%, and the more severe the injury
considered, the greater the reduction. This was also found to be true for particular head injuries such as skull
fractures, intracranial injury and open head wounds. Around one half of children and adolescents less than 19 years
were not wearing a helmet, an issue that needs to be addressed in light of the demonstrated effectiveness of helmets.
Non-helmeted cyclists were more likely to display risky riding behaviour, however, were less likely to cycle in risky
areas; the net result of which was that they were more likely to be involved in more severe crashes."
term bicycle related head injury trends for New South Wales, Australia following mandatory helmet legislation.
This long term study of the effects of the mandatory helmet law in New South Wales found indicators that cycling has
increased and head injuries have dropped over time. "Highlights: Decline in bicycle related head injuries
attributable to mandatory helmet legislation (MHL) has been maintained over the following two decades. The adjusted
estimated post-MHL decline in bicycle related injuries is larger than the immediate impact previously reported (from
29% to 50%). Increase in cycling numbers post-MHL is associated with a similar increase in injuries with the
exception of head injuries. A recent decline in cycling injuries and a continued increase in cycling numbers is
associated with expenditures on cycling infrastructure. The decline in injuries attributable to cycling
infrastructure is more pronounced for head injuries. Posting comments on this blog the
critics continue to debate.
Bicycle Injury Hospitalisations and Deaths in Western Australia -
1981-1995. An Australian Government publication showing that "There was a decrease in the proportion of head
injuries from almost half in 1981-1983 to just over a third in 1993-1995..." Now only available from the National
Library of Australia.
CR 195: Bicycle helmets and Injury Prevention: A Formal Review (2000) "Bicycle helmet efficacy is quantified using a formal meta-analytic
approach based on peer-reviewed studies...The results are based on studies conducted in Australia, the USA, Canada
and the United Kingdom, published in the epidemiological and public health literature in the period 1987- 1998. The
summary odds ratio estimate for efficacy is 0.40 (95% confidence interval 0.29, 0.55) for head injury, 0.42 (0.26,
0.67) for brain injury, 0.53 (0.39, 0.73) for facial injury and 0.27 (0.10, 0.71) for fatal injury. This indicates a
statistically significant protective effect of helmets." BHSI note: Most of the "helmets" in pre-1987 days were not
capable of meeting today's standards. If the study were redone with more recent data we would expect a more
protective effect would emerge.
Monograph 5 - Bicycle Helmet Research Centre for
Accident Research & Road Safety - Queensland (CARRS-Q), November 2010. This is a thorough study of bicycle helmet
effectiveness and issues, recommending that helmet laws in Queensland should not be changed. The conclusion in part
"Current bicycle helmet wearing rates are halving the number of head injuries experienced by Queensland cyclists.
This is consistent with published evidence that mandatory bicycle helmet wearing legislation has prevented injuries
and deaths from head injuries.
It is reasonably clear that it discouraged people from cycling twenty years ago when it was first introduced. Having
been in place for that length of time in Queensland and throughout most of Australia, there is little evidence that
it continues to discourage cycling. There is little evidence that there is a large body of people who would take up
cycling if the legislation was changed."
The Cochrane Collaboration and
Bicycle Helmets. This one is a rant from the May, 2005 issue of Accident Analysis & Prevention about the
Thompson, Rivara and Thompson study that leads off this list. The author, Australian W. J. Curnow, feels that the
data is stale and that helmets have changed. He says hard shell helmets are "rare" (they do have skate-style,
downhill racing and BMX helmets in Australia) and that the protection of soft shells has not been proven. He has lots
of other complaints too, none of which we consider valid. There was a rebuttal from two authors in Canada.
Formal retraction of a paper by Voukelatos and Rissel by the Journal of the Australasian College of Road
Safety. It cites persistent "data errors" as the cause. The paper had concluded that helmet laws did not result
in fewer head injuries.
parents' attitudes and beliefs about bicycle helmet legislation in provinces with and without legislation P. C.
Parkin, MD, et al.,Chronic Diseases and Injuries in Canada, Vol 34, No 1, February 2014. Concludes that "Parents are
highly supportive of bicycle helmet legislation in Canada. They believe that bicycle helmets are effective and that
legislation does not decrease the amount of time a child spends bicycling. There was also a high level of support for
legislation across all ages, and for police enforcement."
Impact of mandatory helmet legislation on bicycle-related head
injuries in children: a population-based study. Macpherson AK, To TM, Macarthur C, Chipman ML, Wright JG, Parkin
PC. Pediatrics 2002; 110(5):e60. Examines the effect of helmet laws on the rate of head injuries in four Canadian
provinces. The bicycle-related head injury rate declined significantly (45% reduction) in provinces where legislation
had been adopted compared with provinces and territories that did not adopt legislation (27% reduction). (Copyright
© 2002 American Academy of Pediatrics--full article is free on the web if you can find it.)
Bicycle Helmet Use in British Columbia: Effects of the Helmet Use Law reports on an evaluation conducted at the
University of North Carolina of the effectiveness of the BC law.
Trends in pediatric and adult bicycling deaths before and after
passage of a bicycle helmet law. An article about Ontario death rates after a helmet law was passed. Appeared in
PEDIATRICS Vol. 122 No. 3 September 2008, pp. 605-610 (doi:10.1542/peds.2007-1776) The article examines
bicycle-related mortality rates in Ontario, Canada, before and after helmet legislation. "For bicyclists 1 to 15
years of age, the average number of deaths per year decreased 52%, the mortality rate per 100000 person-years
decreased 55%, and the time series analysis demonstrated a significant reduction in deaths after legislation." But
for bicyclists 16 and over, there was no significant change. "These findings support promotion of helmet use,
enforcement of the existing law, and extension of the law to adult bicyclists."
effects of provincial bicycle helmet legislation on helmet use and bicycle ridership in Canada by Jessica Dennis,
Beth Potter, Tim Ramsay and Ryan Zarychanski. Journal of Injury Prevention, August 2010.
Data shows that bicycle usage remained constant after helmet laws were adopted in two provinces, and that helmet use
was increased more by all-ages laws than by laws applying only to children. Helmet use data came from surveys, not
Trends in Pediatric and Adult Bicycling Deaths Before and After
Passage of a Bicycle Helmet Law. David E. Wesson, Derek Stephens, Kelvin Lam, Daria Parsons, Laura Spence, and
Patricia C. Parkin. Pediatrics, Sep 2008; 122: 605 - 610. Examines bicycle-related mortality rates in Ontario,
Canada, from 1991 to 2002 among bicyclists 1 to 15 years of age and 16 years of age through adulthood and to
determine the effect of legislation (introduced in October 1995 for bicyclists less than 18 years of age) on
mortality rates. The authors found that "For bicyclists 1 to 15 years of age, the average number of deaths per year
decreased 52%..." Concludes that "The bicycle-related mortality rate in children 1 to 15 years of age has decreased
significantly, which may be attributable in part to helmet legislation. A similar reduction for bicyclists 16 years
of age through adulthood was not identified. These findings support promotion of helmet use, enforcement of the
existing law, and extension of the law to adult bicyclists." Full article is free on the web.
Examining the effectiveness of China's helmet promotion campaign: a before-and-after study
This study found that China's 2020 helmet promotion campaign increased helmet use substantially in all groups, but there was also an increase in badly-fitted helmets. "We estimated a substantial increase in the overall percentage of helmet wearing from 8.8% (95% confidence interval, CI: 8.0–9.6) to 62.0% (95% CI: 60.8–63.2). After controlling for covariates, we noted that helmet wearing increased in all groups" The study has many international references.
Facilitators and barriers to bicycle helmet use: A qualitative evidence synthesis This is an international literature review that concluded:
"We identified 4 themes: 1. Perceptions on helmet design, it's quality and cost together with experiences influencing helmet use (10 studies, low confidence); 2. Perceived risk and benefits of helmet use through a gender lens (10 studies, moderate confidence); 3. Parental strategies influencing children's behavior regarding helmet use (6 studies, moderate confidence); 4. Adoption and enforcement of laws that shape perception and usage of bicycle helmets (8 studies, very low confidence). "
Bicycle helmet use after the introduction of all ages
helmet legislation in an urban community in Alberta, Canada. Karkhaneh et al. Canadian Journal of Public
Health, Vol 102, No 2, April 25, 2011. Evaluated the effect of mandatory bicycle helmet legislation for all ages
in St. Albert, Alberta, using actual field observations. Helmet use increased from 45% to 92% (PR = 2.03; 95% CI:
1.72-2.39) post-legislation. Controlling for other covariates, children were 53% (PR = 1.53; 95% CI: 1.34-1.74) and
adolescents greater than 6 times (PR =6.57; 95% CI: 1.39-31.0) more likely to wear helmets; however, adults (PR =
1.26; 95% CI: 0.96-1.66) did not show a statistically significant change post-legislation. CONCLUSIONS: Helmet
legislation in St. Albert was associated with a significant increase in helmet use among child and adolescent
The impact of compulsory cycle helmet legislation on cyclist head
injuries in New South Wales, Australia - Scott R. Walter, Jake Olivier, Tim Churches, Raphael Grzebieta. Accident Analysis & Prevention, July,
2011. Hospital data modeled the ratio of head to limb injuries and found that cyclist head injuries decreased more
than limb injuries at time of legislation.
This article reports contrary views, but the paper they were based on has been retracted by the publisher for
errors. Jake Olivier wrote a further
article about this situation.
Peer and Adult Companion Helmet Use Is Associated With Bicycle
Helmet Use by Children. Amina Khambalia, Colin MacArthur, and Patricia C. Parkin. Pediatrics, Oct 2005; 116: 939
- 942. A Toronto study that concluded that helmet use by children is closely correlated with use of helmets by their
peers and parents. Free on the web.
Head first: Bicycle-helmet use and our children's safety This
article reviews Canadian injury and helmet use stats, as well as the effect of mandatory helmet laws. The authors
conclude that legislation is called for in the remaining provinces who do not have laws.
- Ontario Government: Cycling Death Review_erratum is a review of All Accidental Cycling Deaths in Ontario From
January 1st, 2006 to December 31st, 2010. This study by the Ontario Coroner found that only one of those under 18 who
died as the result of a cycling collision was wearing a helmet. They recommended many measures including a complete
streets approach to facilities, safety education, legislative changes, paved shoulders, more enforcement, side guards
on heavy trucks and a mandatory helmet law for all ages as part of a helmet promotion campaign. Note that the original
report had different numbers for those under 18. We don't find either of them on the web any more.
- The latest meta: An
evaluation of mandatory bicycle helmet legislation by Ranul Makam in the New Zealand Medical Journal confirms
effectiveness rates: "Their meta-analysis of 40 studies yielded an odds reduction of 51% for head, 69% for serious
head, 33% for facial, and 65% for fatal head injuries."
- Evaluation of New Zealand's bicycle helmet law - Colin F Clarke. New Zealand Medical Journal 10 February
2012, Vol 125 No 1349; ISSN 1175 8716. Concludes that New Zealand's helmet law "has failed in aspects of promoting
cycling, safety, health, accident compensation, environmental issues and civil liberties." This British author details
a decline in cycling in New Zealand, but with no evidence that the helmet law caused it. The full article is available on the cycle-helmets.com site.
Would New Zealand adolescents cycle to school more if allowed to cycle without a helmet? Molina-Garcia J, Queralt
A, Garcia Bengoechea E, Moore A, Mandic S. Journal of Transportation Health 2018; 11: 64-72. Attempts to
answer the question with interviews of 774 adolescents. "Overall, 22.1% of adolescents stated that would cycle to
school more often if helmet use was not mandatory." We are not sure what that proves scientifically, but that's what
the kids said.
Liberty or Death; Don't Tread on Me.
This one is a British paper decrying the ethics of taking liberties away by requiring helmets on adults. (Not so bad
for kids.) The core contention: "The right not to wear helmets is part of a more general right to determine how much
risk to take with our health . . .we all have a strong interest in having the freedom to take risks with our own
health and this general right should, prima facia, be protected however it is expressed." We consider that a
legitimate point of view, but the authors go on to attack the effectiveness of helmets in an attempt to bolster their
ethics argument. "First, cycle helmets in their present form may not be capable of providing significant levels of
protection to the skull and brain." There are many other references on this page refuting that, and refuting their
contention that cycling is so intrinsically safe that nobody needs a helmet. The paper is intended to counter the
British Medical Association's 2010 recommendation to pass a universal UK helmet law. But there is nothing new here.
There are many references to tired old publications from the 20th century, although the ages of some are obfuscated
by "accessed on the web" dates. Curiously, the authors say they don't really believe in the American sentiments they
chose for the title.
Legislation for the compulsory wearing of cycle
helmets a report of the British Medical Association's Board of Science and Education. November 2004. The BMA
examined the evidence and recommended in 2004 that the UK adopt a mandatory helmet law for both children and adults.
They had previously recognized the benefits of helmet use but had feared that a helmet law might reduce cycling.
The Potential for Cycle Helmets to Prevent Injury: a
Review of the Evidence a report by the UK's Transport Research Laboratory attempting to estimate the
effectiveness of helmets. The authors, Hynd, Cuerdon, Reid and Adams, found that in 2008, 34 per cent of riders in
the UK were wearing helmets on major roads, and 17 per cent on minor roads. There are findings on helmet
effectiveness, with the estimate of lives saved by helmets reduced because many of the London cases examined were
cyclists crushed by trucks and buses.
Inequalities in cycle helmet use: cross sectional
survey in schools in deprived areas of Nottingham. This UK study showed that helmet use in low income areas
increased in response to a free helmet program.
Helmet Laws, Helmet Use, and Bicycle
Ridership. A 2016 study of the effect of bicycle helmet laws on helmet and bicycle use among U.S. high school
students in urban jurisdictions. Conclusions: Laws increased helmet use in all jurisdictions, with limited evidence
of reduced cycling. Although sound health policy, laws should be coupled with physical activity promotion.
The effect of an all-ages bicycle helmet law
on bicycle-related trauma. Kett P, Rivara FP, Gomez A, Kirk AP, Yantsides C. J. Community Health 2016;
ePub(ePub): ePub. This study looked at Seattle and King County stats before and after their all-ages helmet law.
Conclusions: While the results do not show an overall decrease in head injuries, they do reveal a decrease in the
severity of head injuries, as well as bicycle-related fatalities, suggesting that the helmet legislation was
effective in reducing severe disability and death, contributing to injury prevention in Seattle and King County. The
promotion of helmet use through an all ages helmet law is a vital preventative strategy for reducing major
bicycle-related head trauma.
Bicycle Helmets and Bicycle-Related Traumatic
Brain Injury in the Netherlands is a study published in 2020 by van den Brand et al that concludes: "In this
study we found that patients with TBI due to bicycle accidents did not wear helmets as often as a comparable control
group. This association could not be established for patients with TBI as a result of a collision between a bicycle
and a motorized vehicle. This study has some limitations, but the results strongly suggest that TBI in adult cyclists
could be reduced if cyclists in the Netherlands would wear a helmet more often. Future research should focus on
establishing the exact frequency of bicycle helmet use in the Netherlands and ways to promote helmet use without
Bicycle helmets - To wear or not to wear? A meta-analyses of the effects of bicycle helmets on injuries is a study done by Alena Høye, Institute of Transport Economics, Oslo. Key findings: "The use of bicycle helmets was found to reduce head injury by 48%, serious head injury by 60%, traumatic brain injury by 53%, face injury by 23%, and the total number of killed or seriously injured cyclists by 34%. Bicycle helmets were not found to have any statistically significant effect on cervical spine injury. There is no indication that the results from bicycle helmet studies are affected by a lack of control for confounding variables, time trend bias or publication bias. The results do not indicate that bicycle helmet effects are different between adult cyclists and children. Bicycle helmet effects may be somewhat larger when bicycle helmet wearing is mandatory than otherwise; however, helmet wearing rates were not found to be related to bicycle helmet effectiveness."
Alcohol Intake and the Pattern of Trauma in Young Adults and Working Aged People Admitted
After Trauma. This 2004 study in Finland demonstrates a link between alcohol and bicycle crashes in that
Bicycle helmet wearing and the risk
of head, face, and neck injury: a French case-control study based on a road trauma registry
Amoros, Chiron, Martin, Laumon. Injury Prevention, doi:10.1136/ip.2011.031815. Results: The fully
adjusted ORs of helmeted versus unhelmeted cyclists are: for AIS1+ head injuries, 0.69 (95% CI 0.59 to 0.81); for
AIS3+ head injuries sustained in urban areas, 0.34 (95% CI 0.15 to 0.65), those sustained in rural areas, 0.07 (95%
CI 0.02 to 0.23); for AIS1+ facial injuries, 0.72 (95% CI 0.62 to 0.83); and for AIS1+ neck injuries, 1.18 (95% CI
0.94 to 1.47). Conclusion: This study confirms the protective effect for head and facial injuries, even though
soft-shell helmets have now become more common. The reduction of risk is greater for serious head injuries. The study
is inconclusive about the risk for neck injuries.
Risk Compensation: A Male Phenomenon?
Results From a Controlled Intervention Trial Promoting Helmet Use Among Cyclists. The authors of this French
study measured the speed of adult urban bicycle riders who had new helmets, and others who did not. The riders were
enrolled in a controlled intervention trial. If helmeted riders rode faster, in theory it would indicate that they
were feeling safer because of the helmet and were riding faster to achieve the same level of risk they normally
experienced without a helmet. The authors state that "In conclusion, helmet use did not result in increased
risk-taking among female cyclists. The average speed difference between helmeted and nonhelmeted male cyclists was
moderate and tended toward zero as overall speed increased." Although the statistical techniques are sophisticated,
the data was sparse (only 3.8% of the observations were helmeted riders) and there are many potentially confounding
factors not explained. Risk-taking on a bicycle is not just a matter of speed. The download costs $20, but here is a
much more detailed article on the same study with free access: Investigating Helmet Promotion for
Cyclists: Results from a Randomised Study with Observation of Behaviour, Using a Semi-Automatic Video System.
This article gives a much better appreciation of this extraordinary study.
Incidence and risk factors of
severe traumatic brain injury resulting from road accidents: A population-based study. This French study found
that the head injury fatality rate increased from 20% in childhood to 71% over 75-year-old. Compared to restrained
car occupants, the odds ratio for having a severe head injury was 18.1 for un-helmeted motorcyclists, 9.2 for
pedestrians, 6.4 for un-helmeted cyclists, 3.9 for unrestrained car occupants and 2.8 for helmeted motorcyclists.
Even after adjustment for several severity factors, male gender and age above 55 were both risk factors. The authors
advocated prevention programs to improve head protection. $30 for the download.
This abstract of a German meeting paper
is titled Specific patterns of bicycle accident injuries - An analysis of correlation between level of head trauma
and trauma mechanism. Although not a journal article, it was presented in 2004 to a Joint Meeting of the
Ungarischen Gesellschaft für Neurochirurgie and the Deutsche Gesellschaft für Neurochirurgie. The authors
noted that cyclists with and without helmets had about the same head injuries, and concluded that helmets were not
working. Although it is difficult to tell from just the abstract, their conclusion seemed to miss the point. For
helmeted riders to be included in their data the cyclist had to be head-injured despite wearing a helmet. But there
is no indication of any effort to determine how many cyclists had not been included in their study because the helmet
prevented their injury, and there is no indication that they knew how hard a blow the helmeted and unhelmeted riders
had suffered. So bare-headed riders injured in lesser impacts were compared with helmeted riders probably injured in
much harder impacts after the helmet's protection had been used up, impacts where a bare-headed rider would have
perhaps died and not been included in a clinical study. We count this one in the ranks of papers written to prove a
point that the authors had already decided on.
The rationale for promotion of bicycle helmet legislation for children up to 18 years (Israel) an article
reviewing the evidence showing the effectiveness of helmets and setting out reasons why Israel should adopt
legislation requiring them.
Bicycle helmets, risk compensation and cyclist types This Norwegian study indicates that there are complex issues in determining how much risk compensation cyclists might do when they use helmets. The conclusion: "The use of [a] bicycle helmet as such does not seem to be related to either accident proneness or speeding."
A Study of the Effectiveness of Bicycle Safety Helmets Among Children in Skaraborg County,
Sweden (1991) Ekman, R and Welander, G. - Karolinska Institute, Department of Social Medicine, Kronan Health
Center and Skaraborg County Council, Department of Health Promotion, Sit Olafsgatan 46, S-52135 Fallioping,
Helmet use and injuries in children's bicycle crashes in the Gothenburg region (2017) Olofsson E, Bunketorp O,
Andersson AL. Safety Sci. 2017; 92: 311-317. Analyzes children's injuries in Gothenburg between 1993 and 2006. "The
adjusted odds of serious or more severe skull/brain injuries and moderate or more severe facial injuries with a
helmet were about one fourth of those without a helmet. "
A decrease in both mild and severe bicycle-related
head injuries in helmet wearing ages - trend analyses in Sweden Peter Berg and Ragnar Westerling, Oxford
Journals-Medicine-Health Promotion International, Vol. 22, Issue 3, pp.191-197. Analyzes trends of
bicycle-related head injuries in Sweden by different age groups. Many references, good discussion of data
difficulties regarding exposure levels and helmet use.
Characteristics of bicycle-related head injuries among
school-aged children in Taipei area. Wang et al, Department of Emergency Medicine, Taipei Medical University
Hospital, Taipei 110, Taiwan. A study of head injuries suffered by child bicyclists in Taipei's incredible traffic.
Concludes that "For children whose main mode of transport is bicycles, the enforcement of helmet legislation,
educational programs in bicycling safety and equipment, and improving the infrastructure for bicycling in urban areas
are needed in Taiwan to reduce potentially debilitating or life-threatening injuries." There is also a statistic
about reduced head injuries to children whose bikes have reflectors that is cited by some helmet sceptics as
Wearing a Bicycle Helmet Can Increase Risk
Taking and Sensation Seeking in Adults. Walker, et al. Psychological Science. This study tracked people wearing
caps or helmets while blowing up a virtual balloon on a computer screen. The researchers found that those in bicycle
helmets took more risk that the balloon would burst, and concluded that "Here, we demonstrated that risk taking
increases in people who are not explicitly aware they are wearing protective equipment; furthermore, this happens for
behaviors that could not be made safer by that equipment. In a controlled study in which a helmet, compared with a
baseball cap, was used as the head mount for an eye tracker, participants scored significantly higher on laboratory
measures of both risk taking and sensation seeking. This happened despite there being no risk for the helmet to
ameliorate and despite it being introduced purely as an eye tracker. The results suggest that unconscious activation
of safety-related concepts primes globally increased risk propensity." There was some adverse reaction to the study, as there was to
Dr. Walker's earlier study of passing clearances.
Wearing a bike helmet leads to less cognitive control, revealed by lower frontal midline theta power and risk
indifference Schmidt et al, Institute of Psychology, Friedrich Schiller University of Jena, Germany. There is no
pretense of scientific method in this study: "We hypothesized that wearing a bike helmet reduces cognitive control
over risky behavior." It is not too surprising that their results proved what they had predicted. They were inspired
by the study produced by Walker et al. (see above)
Risk compensation: revisited and rebutted from Safety
2016, 2(3), 16; doi:10.3390/safety2030016
Barry Pless, Professor Emeritus, Pediatrics and Epidemiology, McGill University
Abstract: This Commentary addresses the ongoing disagreements between many safety advocates who endorse traditional
models of prevention and those who oppose them, arguing that safety measures are offset by risk compensation (RCT).
The debate is especially heated with respect to regulatory or legislative prevention measures. After explaining the
rationale behind risk compensation (aka risk homeostasis theory) (RHT), I provide examples of RCT studies to explain
why I believe they should be rejected. The main basis for my rebuttal, however, rests on data that show steady
declines in unintentional injury mortality, which, according to RCT, should not have occurred. There are many other
reasons for rejecting this theory, and it seems that the time has come for the debate to finally be concluded.
"Thus, perhaps the bottom line of this Commentary is 'enough said'; this is a dead horse that no longer needs to be
The full study is available without charge. It will surely not conclude the debate, but is a well-written critique of
risk compensation theories related to helmets.
The unintended impact of helmet use
on bicyclists' risk-taking behaviors from the Journal of Safety Research, 2021. ISSN 0022-4375 by Lei
Kang, Akshay Vij, Alan Hubbard and David Shaw. Beating the dead issue yet again, with an interesting experimental
design. "Results: Our findings suggest, on average, individuals more likely to wear a helmet are 15.6% more likely to
undertake a risky overtaking maneuver."
Is risk compensation threatening public health in the covid-19
pandemic? from British Medical Journal 370 doi: https://doi.org/10.1136/bmj.m2913 (Published 26 July 2020)
Cite this as: BMJ 2020;370:m2913.
Eleni Mantzari, research associate Department of Public Health and Primary Care, Behaviour and Heath Research Unit,
University of Cambridge, Cambridge, UK, and G James Rubin, Theresa M Marteau, professor, Department of Psychological
Medicine, King's College London, London, UK
Abstract: "Unfounded concerns about risk compensation threaten public health when they delay the introduction of
protective measures such as wearing of face coverings..."
Based on COVID-19 research, but with general evidence about the bogus nature of risk compensation theories.
Bicycle helmets and risky behaviour: a
systematic review: Esmaeilikia M, Radun I, Grzebieta R, Olivier J. Transp. Res. F Traffic Psychol. Behav. 2019;
This systematic review on risk compensation found that:
"Eighteen studies found no supportive evidence helmet use was positively associated with risky behaviour, while three
studies provided mixed findings, i.e., results for and against the hypothesis. For many of these studies, bicycle
helmet wearing was associated with safer cycling behaviour. Only two studies conducted from the same research lab
provided evidence to support the risk compensation hypothesis. In sum, this systematic review found little to no
support for the hypothesis bicycle helmet use is associated with engaging in risky behaviour."
Helmets themselves and performance testing
A price-performance analysis of the
protective capabilities of wholesale bicycle helmets Megan Bland and Steven Rowson, Traffic Injury Prevention.
DOI: 10.1080/15389588.2021.1929943 (2021). The authors tested nine helmet models sold in bulk for helmet promotion
programs at $3.65-$12.95 using the VA Tech STAR oblique impact testing protocol for concussion risk. They found no
price-performance correlation. Results: "Large ranges in kinematic results led to large variations in concussion
risks between helmets, and in turn, large variations in STAR values (13.5-26.2). Wholesale helmet price was not
significantly associated with STAR, although incorporating 30 previous bicycle helmet STAR results produced a weak
negative correlation between price and STAR overall. Nonetheless, the best-performing wholesale helmet produced one
of the lowest overall STAR values for a price of $6.45. Helmet style was instead a superior predictor of STAR, with
multi-sport style helmets producing significantly higher linear accelerations and resulting STAR values than bike
style helmets." (In this case, multi-sport refers to skate-style helmets.) If the $6.45 Model 9 helmet earned a score
of 13.5 that would put it in the range of 5-star helmets the highest rating. The Model 38's score of 26.2 would rank
at the very bottom of the models VA Tech has listed, with one or two stars. The authors recommend buying road helmets
rather than skate-style models, since the skate helmet liners are too stiff for the lower velocity impacts most
riders experience. Keep in mind that the VA Tech testing is focussed on concussion-level impacts, not the most severe
impacts. The helmets came from Helmets R Us, but are not on the current STAR listing.
A New Assessment of Bicycle Helmets: The Brain
Injury Mitigation Effects of New Technologies in Oblique Impacts. Abayazid et al, Annals of Biomedical
Engineering (2021). This study used the basic rotational energy testing rig championed by MIPS for years and found,
not surprisingly, that MIPS, WaveCel and SPIN (POC's version) did reduce rotational energy in an oblique impact. They
also tested the Hovding airbag headgear and found it superior except when the instrumentation was adjusted for longer
duration capture. The three technologies did not perform as well in transverse plane impacts, and the study
speculates on why. The authors provide many charts and graphs. Both CEN and ASTM have been working on methodology for
incorporating similar tests into their bicycle helmet standards. The study uses brain strain methodology that is
widely accepted in some academic circles but has many critics because different brain models give wildly different
results. The impact testing was funded by Sweden's Folksam Insurance Group and the UK's Road Safety Trust.
Skid Tests on a Select Group of Bicycle Helmets to Determine Their Head-Neck Protective
Characteristics by Voigt Hodgson of Wayne State University. A study published by the Michigan Department of
Public Health in 1991. Hard shell, micro shell and no-shell helmets were impacted into slanted concrete. Helmets with
shells slid better, resulting in lower linear g's to the headform (your brain). "Test results predict that hard and
micro-shell helmets provide about equal protection from cervical spine injury. The hard and micro-shell helmets
tended to slide rather than hang up on impact with concrete. This sliding tendency was the mechanism that reduced the
potential for neck injury." This is part of the scientific justification for our Rounder, Smoother, Safer slogan.
Performance of Common Bicycle Helmets. Brain Injury Across the Age Spectrum: Improving Outcomes for Children and
Adults Conference, The Journal of Head Trauma Rehabilitation, 33(3), pp. E87-E88. doi: 10.1097/HTR.0000000000000401.
This shocking study showed that:
"At and above the test line, half of the helmet models (Bell Adrenaline, Smith Overtake, Fox Flux, Bern Macon EPS,
Schwinn Pharos, Bell Trans) exceeded 300g (range 306 to 916g) for between 1 and 15 impacts per model. All but one
model (Nutcase Street Gen 3) exceeded 300g in at least one impact at any location. Most helmets exceeded 300g because
of inadequate energy absorbing liners, inadequate retention systems, or features (e.g., rivets) that directly
contacted and dented the headform.
"We found that half of the helmets failed to meet the CPSC standard at or above the test line. While more tests are
needed across a wider range of helmets, our data suggest that many popular bicycle helmets do not meet the standard
and therefore may be exposing bicyclists to an increased risk of head and brain injuries."
Helmets tested on and below the test
line. MEA Forensic staff and others tested helmets above, on and below the test line. Some met the CPSC standard,
but "The remaining six helmets failed to meet the criterion on and/or above the test line. Our findings indicate that
consumers should not assume that all portions of a helmet provide adequate and equivalent protection. Our findings
also suggest that the CPSC's current system of self-regulation and self-testing by manufacturers does not prevent
substandard bicycle helmets from being sold."
- A modelling framework for local thermal comfort assessment related to bicycle helmet use Bröde et al. "Using curated data on human head sweating and helmet thermal properties, a modelling framework for the thermal comfort assessment of bicycle helmet use is proposed." "Because sweat evaporation is closely related to sweat production, local sweat rates should be estimated with high accuracy for a proper assessment of local thermal discomfort in the heat." "This work was funded as European Union COST Action TU1101 'Towards safer bicycling through optimization of bicycle helmets and usage', also known as HOPE–Helmet Optimization in Europe."
Ranking and Rating Bicycle Helmet Safety
Performance in Oblique Impacts Using Eight Different Brain Injury Models Madelen Fahlstedt et al. Annals of
Biomedical Engineering volume 49, pages 1097-1109 (2021). This study analyzed a single impact dataset with eight
different brain models, getting a lot of variation in results. The authors (including two MIPS founders) concluded
"One specific helmet was rated as 2-star when using one brain model but as 4-star by another model. This could cause
confusion for consumers rather than inform them of the relative safety performance of a helmet. Therefore, we suggest
that the biomechanics community should create a norm or recommendation for future ranking and rating methods." This
ignores the main question: is there a brain model today that gives consistent valid results for helmet testing?
In Situ Strain Measurements Within Helmet Padding During Linear Impact Testing
This study describes a technique to measure the deformation of a helmet and its components during an impact It uses a high-speed X-ray imaging system to describe the deformation at the component level, providing helmet designers with insight into the performance of the helmet.
Helmet Will Save Football. Actually, Probably Not. This excellent NY Times article is deservedly skeptical
about solving concussion and CTE problems in football with better helmets.
The effect of hair and football helmet fit on headform kinematics. MEA Forensic has published a paper on their
research showing that when a helmet slips on the head it reduces peak acceleration and peak angular acceleration. It
is very likely that football helmets are more closely coupled to the head than a bicycle helmet due to their
construction and additional coverage.
- An analysis of energy management thickness for an anti-concussion helmet. Unpublished
paper by Terry Smith and Dan Pomerening examining how thick an EPS foam helmet would have to be to pass the CPSC impact
tests while keeping g's below 100.
3D assessment of damaged bicycle helmets and skull
injuries. A study by G.J.C. van Baar et al used helmet scans and related the helmet damage to injuries suffered
in the crash. They conclude that "Our proposed 3D method of assessing bicycle helmet damage and corresponding head
injuries could offer valuable information for the development and design of safer bicycle helmets." The technique is
likely to be used in forensic research for lawsuits.
Chin strap forces in bicycle
helmets. A study by Torbjorn Andersson of the Swedish National Testing & Research Institute. Published in the
International Journal of Injury Control and Safety Promotion, Vol. 2, Issue 1 March 1995, pp 1-11. DOI:
10.1080/09298349508945743. Measured forces on bike helmet chin straps during impacts on asphalt. Tested with hard
shell, no shell and a ribbed helmet with large vents. The test dummy was suspended from the ceiling impacted by a
chunk of asphalt. Chin strap forces differed appreciably. "The shell helmets did not grip the asphalt layer at all
and did not rotate, which implies that the headform did not rotate either. The non-shell helmets gripped the asphalt
layer in each impact, rotated and transferred this rotation to the headform."
The influence of reduced
friction on head injury metrics in helmeted head impacts. An article on what a slippery helmet means when you
crash, going beyond earlier publications to assess the likelihood of injury using rotational forces as the criterion.
Appeared in Traffic Injury Prevention, Volume 9, Issue 5 October 2008 , pages 483 - 488. DOI:
10.1080/15389580802272427. The article explores the possibility that in some cases reducing surface friction of a
helmet in a crash could increase head injury risk. The goal of was "to demonstrate that reducing friction on the
surface of a helmet decreases the rotational acceleration of the head in some scenarios and increases it in other
scenarios and to discuss the implications for helmet design." The authors conclude that "The theoretical
considerations presented here could be interpreted into a design criterion as follows: friction should be reduced for
each point on the helmet surface until the cone defined by the friction angle and the surface normal at that point no
longer includes the center of gravity of the head-helmet system. Reducing friction beyond this point is not costly in
an averaged sense but neither is it beneficial. It is worth emphasizing that this study has shown that substantial
improvements in helmet performance can result from a reduction in the coefficient of friction and these findings are
supported by other studies (Aare and Halldin, 2003). Furthermore, we argue that while friction may be beneficial in a
particular impact, in an averaged sense it is never beneficial and may be quite costly." This article has
implications for our rounder, smoother, safer theme, and supports our views. "
Protective Effect of Different Types of
Bicycle Helmets. A Norwegian study by Kari Schroder Hansen et al published in 2003 in Traffic Injury Prevention
comparing injury rates in hard shell and "foam" helmets. The authors concluded that "The use of hard shell helmets
reduced the risk of getting injuries to the head. Children less than nine years old that used foam helmets had an
increased risk of getting face injuries. All bicyclists should be recommended to use hard shell bicycle helmets while
cycling." We have not seen the study and don't understand the conclusions.
Bicycle helmets: head impact
dynamics in helmeted and unhelmeted oblique impact tests published in Traffic Injury Prevention, 2013. To assess
the factors, including helmet use, that contribute to head linear and angular acceleration in bicycle crash
simulation tests. Results: Helmet use was the most significant factor in reducing the magnitude of all outcome
variables. Demonstrates that helmets do not increase angular head acceleration.
An overview of the state of the art in
motorcycle helmets published in Accident Analysis and Prevention in 2013. This Portuguese study covers helmet
development, standards and a lot more, purporting to explain basics. We have read only the abstract.
- RedOrbit: 2006 Skull Study Proves Bike Helmets Work. Original study by Dr. Chris A. Sloffer, a neurosurgical
resident at the University of Illinois College of Medicine, in Peoria, et al. This report of the study says they
dropped water-filled child skulls in helmets and the skulls did not fracture. We are not sure what that proves about
reducing brain injury.
2012 Skull Study Proves Bike Helmets Work.
Researchers at the Illinois Neurological Institute and Bradley University tested helmet performance in impact and
crush tests with cadaver skulls. They found that helmet use can reduce by up to 87% the acceleration experienced by
the skull during an impact and can aid the skull in resisting forces up to 470 pounds in a crush accident. Reference:
Mattei TA, Bond BJ, Goulart CR, Sloffer CA, Morris MJ, Lin JJ: Performance analysis of the protective effects of
bicycle helmets during impact and crush tests in pediatric skull models. Journal of Neurosurgery: Pediatrics,
published online, ahead of print, October 2, 2012; DOI: 10.3171/2012.8.PEDS12116
Biokinetics Study of Rotation Acceleration for PHMA
A study of rotational acceleration effects using actual lab tests with bicycle helmets. Prepared by Biokinetics and
Associates of Ottawa for the Protective Headgear Manufacturers Association (now defunct). We are grateful for
permission to post this one, arranged by Biokinetics founder and helmet historian Jim Newman.
Influence of headform mass and inertia
on the response to oblique impacts by Thomas A. Connor, Matt Stewart, Roy Burek & Michael D. Gilchrist (2018):
International Journal of Crashworthiness, DOI: 10.1080/13588265.2018.1525859. Concludes that current headforms
are poorly suited for studying helmet performance in oblique impacts. If you agree with the authors, studies of
helmet performance using current headforms are unlikely to be valid.
- Bicycle Helmet Design. A paper by Mills and Gilchrist that appeared in Proceedings of the Institution of Mechanical
Engineers. The authors, from the University of Birmingham in the UK, used finite element analysis to analyze
theoretical oblique impacts of helmeted heads, concluding that "thicker foam liners of lower compressive yield stress
can protect the head against linear acceleration in 150 J impacts. The peak rotational acceleration of the head was
shown to be only slightly affected by the friction coefficient on the road and, in general, to be insufficient to cause
serious diffuse brain injuries." When conclusions reached by finite element analysis disagree with studies conducted in
physical labs, as the second finding does, the usual cause is the inadequacy of brain models.
Rational Approach to Pedal Cyclist Head
Protection (and other titles) Doctoral thesis by Bart Depreitere. Data also used for articles in various journals
and magazines. Analyzed head injuries of 86 pedal cyclists. Performed 12 mathematical accident reconstructions
(DADS-software) to estimate impact severity. Second phase was an impact study with ten human cadavers, showing longer
energy pulses did more brain damage. A series of 81 impact tests on human skulls showed that energy response varied
and suggested that a helmet filtering out skull base vibration could reduce some injuries. The author hopes that with
more knowledge of brain injury better bicycle helmets will be possible. "In a limited series of impact tests on
helmeted cadavers, it was found that helmets do not unequivocally reduce the head's rotational acceleration and even
may lead to increased accelerations. Helmets did not perform well either with respect to filtering out the
frequencies (skull natural frequencies less than 1500 Hz) at which the skull base vibration was most pronounced. In a
third series of performance tests it was assessed whether helmets could prevent contact between the impactor and the
temporal area in lateral impacts on helmeted cadavers. The helmets that did not cover the temporal area failed to
protect it against such contacts and in one of these tests a skull fracture was produced." More of this analysis is
available from various journal sites locatable by Googling.
Helmet Add-Ons May Not Lower Concussion Risk in
Athletes is a 2015 study of football helmet add-ons, including soft outer shells, spray treatments, pads and
fiber sheets found that "there is no magic concussion prevention product on the market at this time." Another research team tested the
Guardian Cap and concluded that "The Guardian Cap failed to significantly improve the helmets' ability to mitigate impact forces at most locations."
Padded helmet shell covers in American football: a comprehensive laboratory evaluation with preliminary on-field findings found that: "Overall, HARM values were reduced in laboratory impact tests by an average of 25% at 3.5 m/s (range: 9.7 to 39.6%), 18% at 5.5 m/s (range: - 5.5 to 40.5%), and 10% at 7.4 m/s (range: - 6.0 to 31.0%). However, on the field, no significant differences in any measure of head impact magnitude were observed between the bare helmet impacts and padded helmet impacts."
Helmet design based on the optimization of biocomposite
energy-absorbing liners under multi-impact loading Based on finite element analysis and no lab testing this
Portuguese study recommends the use of agglomerated cork for multi-impact helmets.
A modelling framework for local thermal comfort assessment related to bicycle helmet use by Brode et al
This study proposes to assess helmet comfort using computer models of sweat discomfort.
A fiber-optic sensor-embedded and machine learning assisted smart helmet for multi-variable blunt force impact sensing in real time
This study reports that a helmet with an embedded fiber Bragg grating (FBG) sensor can monitor blunt force impacts.
Trends in Smart Helmets With Multimodal Sensing for Health and Safety: Scoping Review
An analysis of smart helmet technology, including its main characteristics and applications for health and safety.
Assessment of the shock adsorption
properties of bike helmets: a numerical/experimental approach Bocciarelli, Carvelli, Mariani & Tenni. (affiliated
with MET helmets). "Laboratory compression and tensile tests were carried out on samples of expanded polystyrene
(EPS) and polycarbonate (PC)...Finite element analyses of a helmet subject to standardized impacts ,,, allowed
assessing the time evolution of the acceleration measured inside the headform (according e.g., to EN 1078)..."
This Swedish masters thesis, although not a peer reviewed journal article, has an excellent discussion on the characteristics of EPS foam.
The SafetyLit service has journal articles by topic, and we found about 400 with a search on bicycle helmet covering 2015-2023. They index about 400 new articles per week, and can send you an email
every week with newly published peer-reviewed journal articles. Each weekly update has one section on Pedestrians and
Bicycles, and one on Protective Headgear. You can also search their huge database going back many years.
- This Google
Scholar search on bicycle helmets found 54,500 scholarly links to bicycle helmet materials.
The European HOPE Study is not a journal article but a full-scale EU
examination of helmets and their effectiveness. Nobody has ever done this before. The Final Report (2015)
- "..most bicyclists in Europe recognise the increased safety of wearing a helmet. However, they provide an extensive
list of reasons why they still do not do so, including thermal discomfort."
- "The primary conclusion of this Working Group is that the full potential of bicycle helmets has not yet been fully
exhausted. In fact, helmets could even provide additional benefits, when protection is extended further on the lateral
- "Working Group 1 is confident in its recommendation that increased usage of bicycle helmets can reduce the number
and severity of head injuries."
- "While literature varies on the overall effectiveness of bicycle helmets, the inconsistent usage and lack of data
mean that absolute conclusions cannot yet be drawn about the overall impact of bicycle helmets on safety." There is
much more in the report, including recommendations for changes in bicycle helmet testing standards.
Science Direct has many more helmet articles, mostly available at about
$30 each. They include articles on motorcycle helmet design and materials, bicycle helmet usage and finite element
testing, and a range of article about other types of helmets. This search brought up hundreds of articles, not all of
them directly relevant.
The Pedestrian and Bicycle Information Center page on Education Resources
and Research has references to more than 150 studies and web pages with bike program and safety info. Here is
for "helmets" on their site.
A Compendium of NHTSA’s Pedestrian and Bicyclist
Traffic Safety Research Projects 1969-2007 is a study by the US National Highway Traffic Safety Administration cataloging all of NHTSA's bike and pedestrian research over the years from 1969 to 2007. It is useful for references.
Our page for researchers has more sources.