Incidence, risk, and protective factors of bicycle crashes: findings from a prospective cohort study in New Zealand

Recreational athletes during downhill-mountain biking (DMB) show high incidence of upper extremity fractures in combination with soft-tissue injuries

Downhill-mountain biking (DMB) is a high-risk sport and often leads to several injuries, especially in non-professional athletes. We retrospectively analyzed the most common injuries and profiled the injury mechanism. Until now, there is no such analysis of injuries by non-professional mountain bike athletes. We collected patient data from patients who suffered from an injury during DMB. The inclusion criteria were (1) injury during the summer season of 2020 and 2021, (2) injury during off-road and downhill mountain bike sports activity, and (3) treatment at the Department of Traumatology of the Klinik Diakonissen Schladming. Patient data was analyzed regarding the type of injury, location of the injury, patient age and gender of the patients. Most patients with injury are at the age of 26-35. Second most are between 36 and 71 years old. The type of injury differs between age and gender. Mostly upper-extremity injuries occur with a high probability of shoulder injuries. In the elderly patients, we found additional injuries of the thorax and chest. To conclude, most common types of injuries are soft-tissue injuries, often in combination with fractures. The risk for injuries is higher for recreational athletes with different injury characteristics than professional athletes.

Odds of self-reported minor cycle crashes with conventional and electric assisted cycles adjusted for cycling frequency in Dutch and Belgian adults a retrospective study

BACKGROUND

Cycling for transportation and recreation is gaining in popularity, especially in older age groups. The rise in electric assisted cycles (EAC) may also have a role to play in this. With an increase in the number of cyclists comes an increase in the prevalence of cycle crashes. However, there is a lack of knowledge on EAC crashes and crash studies including cycle use data. An important question is also whether the high number of serious road injuries among older cyclists, is due to increased risk or more serious consequences in the event of a crash.

STUDY AIM

To compare the odds of reporting a cycle crash on a conventional (CC) against electrically assisted cycle (EAC), while controlling for age, gender, BMI, impairments while cycling, cycling frequency and region of residence.

METHODS

A 12-month retrospective cross-sectional survey-based study, including male and female cyclists aged 40+ years, was conducted in Belgium and the Netherlands. Socio-demographics, physical and mental impairments while cycling (such as lower reaction time), crash details and cycling frequency data were collected. Cyclists were grouped into CC, EAC or both (CC + EAC) based on the type of cycle they used during the study period. Logistic regression models were used to calculate the odds of reporting a cycle crash. Main and interaction effects were studied.

RESULTS

1,919 cyclists were included in the data analysis (63.2 ± 11.1 years; 50% women). 319 (17% of the total sample) cyclists reported a crash in the previous 12 months, of which 36% were EAC crashes. Those reporting a crash were significantly younger compared to those not reporting a crash. The following significant main effects were observed: those cycling on an EAC had a higher odds of reporting a cycle crash compared to those cycling on a CC (OR = 1.41, 95% CI = 1.01-1.97); cyclists in the category average and high on mental impairments while cycling had a higher odds of reporting a cycle crash compared to those in the category low (OR = 1.72, 95% CI = 1.23-2.40 and OR = 3.49, 95% CI = 2.51-4.90, respectively); higher cycling frequency is related to higher odds of reporting a cycle crash (OR = 3.25, 95% CI = 2.25-4.90). A significant interaction effect was observed between age category and gender (OR = 1.93, 95% CI = 1.15-3.26). Post-hoc tests revealed that men in the younger age category (40-64 years) had the highest probability (18.95%) of reporting a cycle crash, whereas men in the oldest age category (65+ years) had the lowest probability (9.99%) of reporting a cycle crash. No significant difference between age categories in women was observed.

CONCLUSION

This study indicates that within a cohort of middle aged and older adults living in regions with high to low cycling modal shares, cycle type, mental impairments while cycling, cycling frequency and region of residence play a significant role in the odds of reporting a (minor) cycle crash. Men in the age category 40-64 years have a significantly higher probability of reporting a cycle crash compared to men of 65+ years. Safety campaigns and instructions should pay particular attention to men in the age category 40-64 years and those with a mental impairment while cycling.

Data linkage for crash outcome assessment: Linking police-reported crashes, emergency response data, and trauma registry records

INTRODUCTION

Traffic crash reports lack detailed information about emergency medical service (EMS) responses, the injuries, and the associated treatments, limiting the ability of safety analysts to account for that information. Integrating data from other sources can enable a better understanding of characteristics of serious crashes and further explain variance in injury outcomes. In this research, an approach is proposed and implemented to link crash data to EMS run data, patient care reports, and trauma registry data.

METHOD

A heuristic framework is developed to match EMS run reports to crashes through time, location, and other indicators present in both datasets. Types of matches between EMS and crashes were classified. To investigate the fidelity of the match approach, a manual review of a sample of data was conducted. A comparative bias analysis was implemented on several key variables.

RESULTS

72.2% of EMS run reports matched to a crash record and 69.3% of trauma registry records matched with a crash record. Females, individuals between 11 and 20 years old, and individuals involved in single vehicle or head on crashes were more likely to be present in linked data sets. Using the linked data sets, relationships between EMS response time and reported injury in the crash report, and between police-reported injury and injury severity score were examined.

CONCLUSION

Linking data from other sources can greatly enhance the information available to address road safety issues, data quality issues, and more. Linking data has the potential to result in biases that must be investigated as they relate to the use-case for the data.

PRACTICAL IMPLICATIONS

This research resulted in a transferable heuristic approach that can be used to link data sets that are commonly collected by agencies across the world. It also provides guidance on how to check the linked data for biases and errors.

Return to Cycling Following Brain Injury: A Proposed Multidisciplinary Approach

Cycling is an important form of exercise, recreation, and transportation. Following traumatic brain injury, the benefits of cycling for health, fitness, and community mobility must be considered alongside potential risk for recurrent injury. In addition to medical concerns and exercise tolerance, key domains include motor function, attention, and visuospatial and executive function, which have previously been explored with regard to driving. Cycling skill is a combination of cognitive and motor function, and can be trained with appropriate education and intervention. We discuss the relationship of brain injury rehabilitation to specific features of cycling, including case studies.

A systematic review of quantitative bias analysis applied to epidemiological research

BACKGROUND

Quantitative bias analysis (QBA) measures study errors in terms of direction, magnitude and uncertainty. This systematic review aimed to describe how QBA has been applied in epidemiological research in 2006-19.

METHODS

We searched PubMed for English peer-reviewed studies applying QBA to real-data applications. We also included studies citing selected sources or which were identified in a previous QBA review in pharmacoepidemiology. For each study, we extracted the rationale, methodology, bias-adjusted results and interpretation and assessed factors associated with reproducibility.

RESULTS

Of the 238 studies, the majority were embedded within papers whose main inferences were drawn from conventional approaches as secondary (sensitivity) analyses to quantity-specific biases (52%) or to assess the extent of bias required to shift the point estimate to the null (25%); 10% were standalone papers. The most common approach was probabilistic (57%). Misclassification was modelled in 57%, uncontrolled confounder(s) in 40% and selection bias in 17%. Most did not consider multiple biases or correlations between errors. When specified, bias parameters came from the literature (48%) more often than internal validation studies (29%). The majority (60%) of analyses resulted in >10% change from the conventional point estimate; however, most investigators (63%) did not alter their original interpretation. Degree of reproducibility related to inclusion of code, formulas, sensitivity analyses and supplementary materials, as well as the QBA rationale.

CONCLUSIONS

QBA applications were rare though increased over time. Future investigators should reference good practices and include details to promote transparency and to serve as a reference for other researchers.

Meta-synthesis of qualitative evidence in road traffic injury prevention: a scoping review of qualitative studies (2000 to 2019)

BACKGROUND

A considerable number of qualitative studies have been published in recent years on the issues that the quantitative studies have limitations on. This study aimed at performing a meta-synthesis on qualitative studies on Road Traffic Injuries (RTIs) with a scoping review approach.

METHODS

This meta-synthesis study was conducted as a scoping review in 2019. The Arkesy and O'Malley framework was applied which has six steps of identifying the research question, identifying the relevant studies, selecting the studies, charting the data, data analysis and reporting the results, and consultation exercise. The required data were gathered by searching the relevant keywords in databases of PubMed, web of knowledge, Scopus, Cochrane Library, Science Direct, Google scholar, Sid, IranMedex. Extracted data were analyzed by the Content-Analysis method.

RESULTS

Finally, 30 studies were included. Extracted data summarized in five main themes and 17 sub-themes. The main themes were: consequences (individual, family, social, financial), the needs of survivors (social support and healthcare), risk factors (general risk factors, risk factors for motorcyclists, risk factors for children and adolescents), barriers of prevention (general barriers, pre-hospital barriers, emergency, and hospital barriers), and prevention solutions (increasing safety, rules and regulations, education, increasing equipment, scientific solutions) of RTIs.

CONCLUSION

This study combined the methods of the scoping review and the meta-synthesis to mapping all qualitative studies on the RTIs, with this approach, this study provides extensive and practical information for policy-makers, managers, practitioners, and researchers in the field of RTIs. Also, by applying this approach, the gaps in the existing knowledge and areas in need of further research are identified.

Cyclist crash rates and risk factors in a prospective cohort in seven European cities

Increased cycling uptake can improve population health, but barriers include real and perceived risks. Crash risk factors are important to understand in order to improve safety and increase cycling uptake. Many studies of cycling crash risk are based on combining diverse sources of crash and exposure data, such as police databases (crashes) and travel surveys (exposure), based on shared geography and time. When conflating crash and exposure data from different sources, the risk factors that can be quantified are only those variables common to both datasets, which tend to be limited to geography (e.g. countries, provinces, municipalities) and a few general road user characteristics (e.g. gender and age strata). The Physical Activity through Sustainable Transport Approaches (PASTA) project was a prospective cohort study that collected both crash and exposure data from seven European cities (Antwerp, Barcelona, London, Örebro, Rome, Vienna and Zürich). The goal of this research was to use data from the PASTA project to quantify exposure-adjusted crash rates and model adjusted crash risk factors, including detailed sociodemographic characteristics, attitudes about transportation, neighbourhood built environment features and location by city. We used negative binomial regression to model the influence of risk factors independent of exposure. Of the 4,180 cyclists, 10.2 % reported 535 crashes. We found that overall crash rates were 6.7 times higher in London, the city with the highest crash rate, relative to Örebro, the city with the lowest rate. Differences in overall crash rates between cities are driven largely by crashes that did not require medical treatment and that involved motor-vehicles. In a parsimonious crash risk model, we found higher crash risks for less frequent cyclists, men, those who perceive cycling to not be well regarded in their neighbourhood, and those who live in areas of very high building density. Longitudinal collection of crash and exposure data can provide important insights into individual differences in crash risk. Substantial differences in crash risks between cities, neighbourhoods and population groups suggest there is great potential for improvement in cycling safety.

Crash histories, safety perceptions, and attitudes among Virginia bicyclists

INTRODUCTION

Cycling injury and fatality rates are on the rise, yet there exists no comprehensive database for bicycle crash injury data.

METHOD

Widely used for safety analysis, police crash report datasets are automobile-oriented and widely known to under-report bicycle crashes. This research is one attempt to address gaps in bicycle data in sources like police crash reports. A survey was developed and deployed to enhance the quality and quantity of available bicycle safety data in Virginia. The survey captures bicyclist attitudes and perceptions of safety as well as bicycle crash histories of respondents.

RESULTS

The results of this survey most notably show very high levels of under-reporting of bicycle crashes, with only 12% of the crashes recorded in this survey reported to police. Additionally, the results of this work show that lack of knowledge concerning bicycle laws is associated with lower levels of cycling confidence. Count model results predict that bicyclists who stop completely at traffic signals are 40% less likely to be involved in crashes compared to counterparts who sometimes stop at signals. In this dataset, suburban and urban roads with designated bike lanes had more favorable injury severity profiles, with lower percentages of severe and minor injury crashes compared to similar roads with a shared bike/automobile lane or no designated bike infrastructure.

Mountain Biking Injuries

With the increasing popularity of mountain biking, also known as off-road cycling, and the riders pushing the sport into extremes, there has been a corresponding increase in injury. Almost two thirds of acute injuries involve the upper extremities, and a similar proportion of overuse injuries affect the lower extremities. Mountain biking appears to be a high-risk sport for severe spine injuries. New trends of injury patterns are observed with popularity of mountain bike trail parks and freeride cycling. Using protective gear, improving technical proficiency, and physical fitness may somewhat decrease the risk of injuries. Simple modifications in bicycle-rider interface areas and with the bicycle (bike fit) also may decrease some overuse injuries. Bike fit provides the clinician with postural correction during the sport. In this review, we also discuss the importance of race-day management strategies and monitoring the injury trends.

Mechanisms underlying cognitive conspicuity in the detection of cyclists by car drivers

OBJECTIVE

The aim of this study was to evaluate the visibility of cyclists for motorists in a simulated car driving task.

BACKGROUND

In several cases involving collisions between cars and cyclists, car drivers failed to detect the latter in time to avoid collision because of their low conspicuity.

METHOD

2 groups of motorists (29.2 years old), including 12 cyclist-motorists and 13 non-cyclist-motorists, performed a vulnerable road user detection task in a car-driving simulator. They had to detect cyclists and pedestrians in an urban setting and evaluate the realism of the cyclists, the traffic, the city, the infrastructure, the car driven and the situations. Cyclists appeared in critical situations derived from previous accounts given by injured cyclists and from cyclists' observations in real-life situations. Cyclist's levels of visibility for car drivers were either high or low in these situations according to the cyclists.

RESULTS

Realism scores were similar and high in both groups. Cyclist-motorists had fewer collisions with cyclists and detected cyclists at a greater distance in all situations, irrespective of cyclist visibility. Several mechanisms underlying the cognitive conspicuity of cyclists for car drivers were considered.

CONCLUSION

The attentional selection of a cyclist in the road environment during car driving depends on top-down processing.

APPLICATION

We consider the practical implications of these results for the safety of vulnerable road users and future directions of research.

Reflective Tape Applied to Bicycle Frame and Conspicuity Enhancement at Night

OBJECTIVE

Four studies were conducted to assess bicyclist conspicuity enhancement at night by the application of reflective tape (ECE/ONU 104) to the bicycle rear frame and to pedal cranks.

BACKGROUND

Previous studies have tested the benefits of reflective markings applied to bicyclist clothing. Reflective jackets however need to be available and worn while reflective markings enhance conspicuity without any active behavior by the bicyclist.

METHOD

In the first study, reflective tape was applied to the rear frame. Detection distance was compared in four conditions: control, rear red reflector, high visibility jacket, and reflective tape. In the second study, the same conditions were studied with night street lighting on and off. In the third study, detection and recognition distances were evaluated in rainy conditions. In the fourth study, visibility was assessed with the reflective tape applied to pedal cranks.

RESULTS

In the first study, the application of reflective markings resulted in a detection distance of 168.28 m. In the second study, the detection distance with reflective markings was 229.74 m with public street light on and 256.41 m with public street light off. In rainy conditions, detection distance using the reflective markings was 146.47 m. Reflective tape applied to pedal cracks resulted in a detection distance of 168.60 m.

CONCLUSION

Reflective tape applied to the rear bicycle frame can considerably increase bicyclist conspicuity and safety at night.

APPLICATION

Reflective tape is highly recommended to complement anterior and rear lights in bicycle riding at night.

The role of intersection and street design on severity of bicycle-motor vehicle crashes

Background

Safety concerns are a major barrier to cycling. Intersection and street design variables such as intersection angles and street width might contribute to the severity of crashes and the safety concerns. In this study we examined whether these design variables were associated with bicycle-motor vehicle crashes (BMVC) severity.

Methods

Using the geographical information system and latitudes/longitudes recorded by the police using a global positioning device, we extracted intersection angles, street width, bicycle facilities, posted speed limits and annual average daily traffic from 3266 BMVC data from New York City police records. Additional variables about BMVC, including age and sex of the bicyclist, time of the day, road surface conditions, road character, vehicle type and injury severity, were obtained from police reports. Injury severity was classified as severe (incapacitating or killed) or non-severe (non-incapacitating, possible injury). The associations between injury severity and environment design variables were examined using multivariate log-binomial regression model.

Findings

Compared with crashes at orthogonal intersections, crashes at non-orthogonal intersections had 1.37 times (95% CI 1.05 to 1.80) and non-intersection street segments had 1.31 times (95% CI 1.01 to 1.70) higher risk of a severe injury. Crashes that involved a truck or a bus were twice as likely to result in a severe injury outcome; street width was not significantly associated with injury severity.

Conclusion

Crashes at non-orthogonal intersections and non-intersection segments are more likely to result in higher injury severity. The findings can be used to improve road design and develop effective safety interventions.

An exposure based study of crash and injury rates in a cohort of transport and recreational cyclists in New South Wales, Australia

This paper examines self-reported prospectively collected data from 2038 adult transport and recreational cyclists from New South Wales (Australia) to determine exposure-based incident crash and injury rates. During 25,971 days of cycling, 198 crashes were reported, comprising approximately equal numbers of falls and collisions. The overall crash rate was 0.290 (95% CI, 0.264-0.319) per 1000km or 6.06 (95% CI, 5.52-6.65) per 1000h of travel. The rate of crashes causing any injury (self-treated, or medically attended without overnight hospital stay) was 0.148 (95% CI, 0.133-0.164) per 1000km or 3.09 (95% CI, 2.79-3.43) per 1000h of travel. The rate of crashes causing a medically attended injury (without overnight hospital stay) was 0.023 (95% CI, 0.020-0.027) per 1000km or 0.49 (95% CI, 0.43-0.56) per 1000h of travel. No injuries requiring an overnight stay in hospital were reported on days meeting the inclusion criteria. After adjustment for exposure in hours, or for the risks associated with different infrastructure utilisation, the rates of crashes and medically attended injuries were found to be greater for females than males, less experienced than more experienced cyclists, and for those who rode mainly for transport rather than mainly for recreation. Comparison of estimated crash and injury rates on different infrastructure types were limited by the small number of events, however findings suggest that the separation of cyclists from motorised traffic is by itself not sufficient to ensure safe cycling.

The role of conspicuity in preventing bicycle crashes involving a motor vehicle

Background: Bicycle use, despite its proven health and other benefits, is rarely part of everyday travel for many people due to the perceived risk of injury from collision crashes. This article investigated the role of physical vs. attention conspicuity in preventing bicycle crashes involving a motor vehicle in New Zealand. Methods: The Taupo Bicycle Study involved 2590 adult cyclists recruited in 2006 (43.1% response rate) and followed for bicycle crash outcomes through linkage to four national databases. A composite measure of physical conspicuity was created using latent class analysis based on the use of fluorescent colours, lights and reflective materials, and the main colour of top, helmet and bike frame. Attention conspicuity was assessed based on regional differences in travel patterns and the amount of riding in a bunch. Cox regression modelling for repeated events was performed with multivariate adjustments. Results: During a median follow-up period of 6.4 years, 162 participants experienced 187 bicycle–motor vehicle crashes. The crash risk was not predicted by the four latent classes identified and the amount of bunch riding but was higher in Auckland, the region with the lowest level of bicycle use relative to car use. In subgroup analyses, compared to other latent classes, the most physically conspicuous group had a higher risk in Auckland but a lower risk in other regions. Conclusion: Conspicuity aids may not be effective in preventing bicycle–motor vehicle crashes in New Zealand, particularly in Auckland, where attention conspicuity is low.

What influences the association between previous and future crashes among cyclists? A propensity score analysis

BACKGROUND

It is known that experience of a previous crash is related to incidence of future crashes in a cohort of New Zealand cyclists. This paper investigated if the strength of such association differed by crash involvement propensity and by the need for medical care in the previous crash.

METHODS

The Taupo Bicycle Study involved 2590 adult cyclists recruited in 2006 and followed over a median period of 4.6 years through linkage to four national databases. The crash involvement propensity was estimated using propensity scores based on the participants' demographic, cycling and residential characteristics. Cox regression modelling for repeated events was performed with multivariate and propensity score adjustments. Analyses were then stratified by quintiles of the propensity score.

RESULTS

A total of 801 (31.0%) participants reported having experienced at least one bicycle crash in the twelve months prior to the baseline survey. They had a higher risk of experiencing crash events during follow-up (hazard ratio (HR): 1.43; 95% CI: 1.28, 1.60) but in the stratified analysis, this association was significant only in the highest two quintiles of the propensity score where the likelihood of having experienced a crash was more than 33%. The association was stronger for previous crashes that had received medical care (HR 1.63; 95% CI: 1.41, 1.88) compared to those that had not (HR 1.30; 95% CI: 1.14, 1.49).

CONCLUSIONS

Previous crash experience increased the risk of future crash involvement in high-risk cyclists and the association was stronger for previous crashes attended medically. What distinguishes the high risk group warrants closer investigation, and the findings indicate also that health service providers could play an important role in prevention of bicycle crash injuries.

Estimating bias from loss to follow-up in a prospective cohort study of bicycle crash injuries

Background

Loss to follow-up, if related to exposures, confounders and outcomes of interest, may bias association estimates. We estimated the magnitude and direction of such bias in a prospective cohort study of crash injury among cyclists.

Methods

The Taupo Bicycle Study involved 2590 adult cyclists recruited from New Zealand's largest cycling event in 2006 and followed over a median period of 4.6 years through linkage to four administrative databases. We resurveyed the participants in 2009 and excluded three participants who died prior to the resurvey. We compared baseline characteristics and crash outcomes of the baseline (2006) and follow-up (those who responded in 2009) cohorts by ratios of relative frequencies and estimated potential bias from loss to follow-up on seven exposure-outcome associations of interest by ratios of HRs.

Results

Of the 2587 cyclists in the baseline cohort, 1526 (60%) responded to the follow-up survey. The responders were older, more educated and more socioeconomically advantaged. They were more experienced cyclists who often rode in a bunch, off-road or in the dark, but were less likely to engage in other risky cycling behaviours. Additionally, they experienced bicycle crashes more frequently during follow-up. The selection bias ranged between −10% and +9% for selected associations.

Conclusions

Loss to follow-up was differential by demographic, cycling and behavioural risk characteristics as well as crash outcomes, but did not substantially bias association estimates of primary research interest.

The role of multilevel factors in geographic differences in bicycle crash risk: a prospective cohort study

BACKGROUND

Regular cycling plays an important role in increasing physical activity levels but raises safety concerns for many people. While cyclists bear a higher risk of injury than most other types of road users, the risk differs geographically. Auckland, New Zealand's largest urban region, has a higher injury risk than the rest of the country. This paper identified underlying factors at individual, neighbourhood and environmental levels and assessed their relative contribution to this risk differential.

METHODS

The Taupo Bicycle Study involved 2590 adult cyclists recruited in 2006 and followed over a median period of 4.6 years through linkage to four national databases. The Auckland participants were compared with others in terms of baseline characteristics, crash outcomes and perceptions about environmental determinants of cycling. Cox regression modelling for repeated events was performed with multivariate adjustments.

RESULTS

Of the 2554 participants whose addresses could be mapped, 919 (36%) resided in Auckland. The Auckland participants were less likely to be Māori but more likely to be socioeconomically advantaged and reside in an urban area. They were less likely to cycle for commuting and off-road but more likely to cycle in the dark and in a bunch, use a road bike and use lights in the dark. They had a higher risk of on-road crashes (hazard ratio: 1.47; 95% CI: 1.22, 1.76), of which 53% (95% CI: 20%, 72%) was explained by baseline differences, particularly related to cycling off-road, in the dark and in a bunch and residing in urban areas. They were more concerned about traffic volume, speed and drivers' behaviour.

CONCLUSIONS

The excess crash risk in Auckland was explained by cycling patterns, urban residence and factors associated with the region's car-dominated transport environment.