Helmet Use Among Users of the Citi Bike Bicycle-Sharing Program: A Pilot Study in New York City

Public bikeshare programs are becoming increasingly common in the United States and around the world. These programs make bicycles accessible for hourly rental to the general public. We seek to describe the prevalence of helmet use among adult users of bikeshare programs and users of personal bicycles in 2 cities with recently introduced bikeshare programs (Boston, MA, and Washington, DC). We performed a prospective observational study of adult bicyclists in Boston, MA, and Washington, DC. Trained observers collected data during various times of the day and days of the week. Observers recorded the sex of the bicycle operator, type of bicycle, and helmet use. All bicycles that passed a single stationary location in any direction for a period of between 30 and 90 minutes were recorded. There were 43 observation periods in 2 cities at 36 locations; 3,073 bicyclists were observed. There were 562 (18.3%; 95% confidence interval [CI] 16.4% to 20.3%) bicyclists riding shared bicycles. Overall, 54.5% of riders were unhelmeted (95% CI 52.7% to 56.3%), although helmet use varied significantly with sex, day of use, and type of bicycle. Bikeshare users were unhelmeted at a higher rate compared with users of personal bicycles (80.8% versus 48.6%; 95% CI 77.3% to 83.8% versus 46.7% to 50.6%). Logistic regression, controlling for type of bicycle, sex, day of week, and city, demonstrated that bikeshare users had higher odds of riding unhelmeted (odds ratio [OR] 4.4; 95% CI 3.5 to 5.5). Men had higher odds of riding unhelmeted (OR 1.6; 95% CI 1.4 to 1.9), as did weekend riders (OR 1.3; 95% CI 1.1 to 1.6). Use of bicycle helmets by users of public bikeshare programs is low. As these programs become more popular and prevalent, efforts to increase helmet use among users should increase. Copyright © 2012. Published by Mosby, Inc.

Evidence exists to suggest that bicycle helmets may reduce the risk of head injuries to cyclists, however helmets are not uniformly worn by all bicycle users. Legislation has been enacted in some countries to mandate helmet use by cyclists, however the issue remains controversial with opponents arguing that this may inhibit people from bicycle riding and thus from gaining the associated health benefits, or that other countermeasures may have been responsible for decline in head injuries.

Introduction Urban cycling promotes healthy living and also minimises environmental pollutants from vehicle emissions. Bike-sharing initiatives, therefore, provide communities with a means to an active healthy lifestyle via a sustainable means of transportation.1 Multiple variations of bike-sharing programmes have evolved across the world in the last 46 years, yet the core design among all programmes remains the same—a finite number of bikes are placed throughout a community for citizens and visitors to ‘borrow’ at their leisure for shorter commutes within designated community zones.1 The target population for these programmes is within-city commuters who can benefit from the use of a temporary bicycle and avoid the worry of parking and locking a bike while at their destination. The most prominent bike-sharing programme in North America is BIXI (named according to a combination of the elements of the programme: ‘BIcycle’ and ‘taXI’). BIXI was also the first bike-sharing company in Canada, initially in Montreal in 2009 and to the Toronto downtown core on 3 May 2011.2 Eighty solar-panelled stations were placed throughout the city (Figure 1). Each station consists of a pay station and bike docks, distributed according to population density, frequent travel paths and frequent bicyclist locations2 (Figure 2). Figure 1 BIXI bike docking station locations, Toronto, 2011. Figure 2 BIXI bike kiosk, with pay station and bike dock, Toronto, 2011. Users of BIXI bikes can subscribe for a 1-year or 30-day access pass or they can rent a bike by purchasing a 24 h or 72 h access pass. Requirements stated for usage of the BIXI bikes are that cyclists are 18 years of age or older and at least 1.24 m tall; however, after a credit card has been registered or an account has been created, there is no actual method of monitoring who rides the bicycle. Furthermore, there is no requirement for helmets to be worn while on the bicycle, though BIXI encourages riders to wear a helmet while cycling.2 Cyclists over 18 years of age in Toronto make the choice of whether or not to wear a bicycle helmet because helmet legislation in Ontario only applies to children. It was initially estimated that bicycle helmets decrease the risk of head injury by 85%.3 More recent estimates question whether the protective effect is that high, but meta-analyses consistently demonstrate that bicycle helmets prevent head injuries.4 The 2001–2007 Canadian Community Health Surveys showed that 41% of youth and adults in Ontario regularly use helmets while cycling.5 Recent observational data revealed that only 50% of cyclists use helmets in the Greater Toronto Area.6 In the City of Toronto, 13 475 collisions were reported between cyclists and motor vehicles between 1986 and 1996, resulting in 38 cyclist fatalities.7 In the USA, as high as 500 000 emergency care visits are attributable to injuries sustained while riding a bicycle, resulting in 900 deaths annually. Head injuries and facial traumas represent one-third of these emergencies, with three-quarters of all bicycle-related deaths being attributable to head injuries.8 With the advent of the BIXI bike-sharing system throughout downtown Toronto and the promotion of bicycle use for commuters, we were interested in examining the prevalence of helmet use by BIXI bike users. To our knowledge, no study has examined the prevalence of helmet use in bike-sharing programmes. The current study compared the use of helmets by cyclists choosing to use BIXI bikes with personal bike riders in the City of Toronto. We hypothesized that the proportion of helmet users using BIXI bikes would be significantly lower than those on personal bikes because there is no way to obtain a helmet at the same time as a BIXI is hired. There are little data about helmet use in bike-sharing systems but the information available suggests lower helmet use if the helmet is not supplied with the bike.9 Methods We used a cross-sectional design to determine the proportion of helmet users in downtown Toronto, Canada, for cyclists on personal bikes versus those on BIXI bikes. During an observational period of 1 h, a researcher observed how many cyclists on personal bikes and how many cyclists on BIXI bikes wore or did not wear helmets. Observations were made between July and September 2011 and took place during weekday ‘commuter hours’ (ie, between 07:00 and 10:00 or between 15:00 and 18:00). As the BIXI bike main use is to facilitate transportation along short distances,2 and most of the cyclist commuter traffic occurs during these ‘rush hour’ time periods, this time period was chosen to maximise the number of both BIXI bike and personal bike cyclists observed. The main exposure variable was type of bicycle. For the purposes of this study, a ‘bicycle’ or ‘bike’ was defined by the researchers to constitute a two-wheeled, non-fuel-consuming foot pedal-based method of transportation, where the rider is seated and can hold handlebars in front of them. The ‘BIXI bike’ was identified by its characteristic BIXI shape and/or colours,2 whether being removed or returned from the docking station or being ridden past the point of observation. A ‘personal bicycle’ was defined as any bicycle of a brand other than BIXI. The outcome of interest was helmet use. A ‘helmet’ was defined for the purposes of this project to constitute a solid protection device worn on the head, with a chinstrap, as a means of promoting personal safety to protect the head from impact in the event of a fall or collision. Observed sex of the bicycle riders was also recorded as a covariate to understand differences in helmet use by sex. Using the map of the BIXI bike docking, operational docking stations were assigned numbers from 1 to 79 sequentially from north-east to south-west. Twenty-five operational stations were randomly selected to designate observation points for the study. During each observation period, a researcher sat in a location with the BIXI bicycle docking station in clear view and noted all cyclists within view (approximately 20 m radius from the BIXI bicycle docking station), no matter which direction they were travelling. Cyclists of all ages were included in the study. No contact was made with the cyclists. Ethical approval was obtained from the research ethics review board at the Hospital for Sick Children in Toronto, Ontario. A tally was collected for one of four categories: (1) BIXI bike riders with a helmet, (2) BIXI bike riders without a helmet, (3) personal bike riders with a helmet or (4) personal bike riders without a helmet. Each category was subdivided by observed sex (male, female or unsure). The required sample size for each of the two groups (BIXI bike cyclists and personal bike cyclists) was based on calculations using the formula for sample size calculations for two independent sample tests for proportions with an estimated effect size of 10% and an estimated proportion of 50% of helmet use in personal bike users6 for a two-sided test with a 5% level of significance, 80% power. The sample size calculation revealed that 407 subjects were needed per group. Proportions of helmet users in BIXI bike cyclists and personal bike cyclists were calculated and compared between groups by χ2 analysis using Epi Info (V.3.5.3) StatCalc. Each group was stratified by sex (male, female or ‘unsure’), and the proportion of helmet users within groups by sex was calculated. Results A total of 6732 cyclists were observed, including 306 BIXI bike cyclists and 6426 personal bike cyclists. When stratified by sex, a total of 4307 male cyclists and 2399 female cyclists were observed. Within groups, there were 234 male BIXI cyclists and 72 female BIXI cyclists, and 4073 male and 2327 female cyclists on personal bikes. For 24 helmet users and two non-helmet wearing cyclists on personal bikes, male or female designation could not be assigned; however, this represented a very small number of cyclists observed (0.4%) and thus these observations were not included in the analysis by sex. The remaining 6706 observations were included in the analysis. Twenty-one per cent of bike riders wore helmets while on BIXI bikes. This was significantly lower than the prevalence of helmet use by personal bike riders (51.7%; uncorrected χ2=110.48, p<0.0001). Both male and female personal bike riders were statistically significantly more likely to wear helmets compared with male and female BIXI bike riders (males: 47.9% vs 20.1%, respectively; uncorrected χ2=68.84, p<0.0001, females: 57.8% vs 23.6%, respectively; uncorrected χ2=33.26, p<0.0001). The results for across-group comparisons of helmet use in BIXI bike users and personal bike users are summarised in table 1. Table 1 Observed helmet use by bicycle type, Toronto, 2011 BIXI bike Personal bike χ2 p Value Riders (n) Helmet, n (%) Riders (n) Helmet, n (%) Total observed 306 64 (20.9) 6426 3320 (51.7) 110.48 <0.0001 Females 72 17 (23.6) 2327 1345 (57.8) 33.26 <0.0001 Males 234 47 (20.1) 4073 1951 (47.9) 68.84 <0.0001 Could not determine sex 0 0 (–) 26 24 (92.3) (Not analysed) The proportion of riders using helmets was lower on BIXI bicycles and this was statistically significant overall and by sex. Compared with male bike riders, female bike riders were more likely to wear helmets. On personal bikes, women wore helmets more often than men (57.8% vs 47.9%, respectively; χ2=58.10, p<0.0001). On BIXI bikes, gender differences in helmet use were not statistically significant (23.6% of females vs 20.1% of males, respectively; χ2=0.41, p<0.5201). Overall, whether riding a BIXI bike or a personal bike, 3384 of 6732 cyclists observed (50.3%) wore helmets. The observed prevalence of BIXI bike usage in Toronto was 4.5%. Discussion The proportion of BIXI bike users (64, 20.9%) who were wearing a helmet, regardless of sex, was significantly lower than the proportion of personal bike users (3320, 51.7%) wearing a helmet. This means that, although BIXI was introduced with the purpose to promote the use of cycling for short commutes within the city, the BIXI bike programme appears to decrease the already-low proportion of helmet users. Since the use of helmets while cycling has been recognised as a means of reducing significant head injuries, severe facial trauma and even death,3 4 8 10 the advent of a bike-sharing programme that decreases helmet use may increase the risk of severe injury and/or fatalities in the event of a collision while cycling. This is especially dangerous in an urban centre such as Toronto, where cyclists often are found alongside motor vehicles on busy streets in peak commuting hours. As has been replicated in previous studies,5 11 a large sex difference was observed both with respect to total cyclists and helmet users. Although women were less likely to ride a bicycle overall, women who did use a bicycle were more likely to wear a helmet. This same pattern translated to BIXI bike users as well, with women less likely to use the BIXI bikes. This study represents the first investigation (to our knowledge) of helmet use in a bike-sharing system. A similar pattern may extend to bike-sharing systems worldwide. As of 2008, there have been fatalities reported while using bike-sharing systems internationally: three fatalities in Paris's Velib programme, three collisions in New Zealand's NextBike, one collision in Hangzhou's bike-sharing system and one in the North American BIXI system.1 Given the nature of collision data, these statistics may be under-reported. Since helmet use has been shown to protect against severe injuries and fatalities among collisions while cycling,3 4 8 10 this suggests that bike-sharing systems, such as BIXI, should be accompanied by actions to promote helmet use. However, as bike-sharing programmes cater to cyclists on-the-go within urban centres,1 it is imperative that solutions to promote helmet use be amenable to the commuter population and available at the point of bike rental. One difficulty noted internationally is that helmet use may be legislated (or not) by a municipal, state/province or nationally country. In cities where helmet use is mandatory, bike-sharing systems have already begun to address the problem of low helmet use, providing a model through which other bike-sharing systems may approach this dilemma in injury prevention.12 As helmets are mandatory for cyclists in Australia, a bike-sharing system in Melbourne piloted a project where helmets could be purchased or rented through vending machines at the point of bike rental or at local convenience stores around the city.13 Pending helmet uptake data through this pilot, other bike-sharing companies like BIXI could model this project in order to promote helmet use within their consumers. BIXI bike could also work towards providing machines near BIXI stations for helmet dispensing at the point of BIXI bike rental. There are several limitations associated with the current study. This was the first study of its kind to observe and count BIXI bike riders and personal bike riders. The fact that only one observer who was not blinded to the hypothesis collected the data for the study could have introduced a data collection bias. However, since the observer was measuring an objective outcome through the tallying of bicyclists in the area at each station, it is unlikely that any significant personal or subjective bias was introduced. Furthermore, this study only observed cyclists within the presumed ‘commuter’ hours within the downtown core such that the main population targeted for the study was cyclists commuting to work or to school. Previous studies have found that statistics of helmet use vary with income and education,11 though in this study, all riders, regardless of attire or presumed reason for riding the bicycle, were counted towards the study population. Furthermore, although all observations were made during commuter hours, the locations of the randomly selected BIXI bike stations spanned many areas of downtown Toronto, including financial districts, local parks, intercity areas and school campuses.2 This layout in BIXI bike stations allows the programme to cater to a wide array of Torontonians and helped to increase the diversity of our study population to be representative of the natural Toronto population. This study did not classify cyclists by age; as a result, all analyses were conducted regardless of the age of the cyclists. Patterns of helmet use have been reported to vary with age, with youth and adolescents in Ontario most likely to wear a helmet.11 BIXI bicycles are only available for those 18 and over, so it is unlikely that the presence of children under the helmet legislation would have significantly impacted the study's results. Finally, individual cyclists were not identified so may have been observed more than once. With an increasing focus on Toronto to be a healthy, environmentally friendly city, cycling continues to be a promising sustainable means of transportation. Although the BIXI bike programme has provided an alternate means for Torontonians to use a bicycle that is publically available for short-term within-city routes,2 its indirect negative effect on helmet use for cyclists poses a threat to cyclists' safety. Efforts to promote cycling while protecting cyclists from severe injury should be made a priority in the promotion of a healthy and safe Toronto. Supplementary Material Supporting Statement Author's manuscript Reviewer comments